Avian Influenza Weekly Update Number 986| 1 Avian Influenza Weekly Update Number 986 21 February 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 14 to 20 February 2025, no new cases of human infection with avian influenza A(H9N2) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 13 December 2024. From 1 January 2003 to 12 December 2024, a total of 261 cases of human infection with avian influenza A(H5N1) virus have been reported from five countries within the Western Pacific Region (Table 1). Of these cases, 142 were fatal, resulting in a case fatality rate (CFR) of 54%. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 12 December 2024), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020 2021 2022 2023 2024 Total C D C D C D C D C D C D C D C D C D Australia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 Cambodia 9 7 47 30 0 0 0 0 0 0 0 0 6 4 10 2 72 43 China 38 25 9 5 6 1 0 0 0 0 1 1 1 0 1 0 56 32 Lao PDR 2 2 0 0 0 0 1 0 0 0 0 0 0 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 0 0 0 0 1 0 0 0 1 1 129 65 Total 161 91 71 42 6 1 1 0 0 0 2 1 7 4 13 3 261 142 NB: This table is updated following updates from the source. Globally, from 1 January 2003 to 12 December 2024, 954 cases of human infection with avian influenza A(H5N1) virus were reported from 24 countries. Of these 954 cases, 464 were fatal (CFR of 49%). Human infection with avian influenza A(H5N6) virus From 14 to 20 February 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 14 to 20 February 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. Avian Influenza Weekly Update Number 986| 2 No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people, published on 20 December 2024. Human infection with avian influenza A(H3N8) virus From 14 to 20 February 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 14 to 20 February 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 14 to 20 February 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Of the 1 568 human infections with avian influenza A(H7N9), 33 have reported mutations in the hemagglutinin gene indicating a change to high pathogenicity in poultry. These 33 cases were from Taiwan, China (one case had a travel history to Guangdong), Guangxi, Guangdong, Hunan, Shaanxi, Hebei, Henan, Fujian, Yunnan, and Inner Mongolia. No increased transmissibility or virulence of the virus within human cases related to the HPAI A(H7N9) virus has been detected. Human infection with avian influenza A(H9N2) virus From 14 to 20 February 2025, four new cases of human infection with avian influenza A(H9N2) virus were reported from China in the Western Pacific Region. The first case was a 72-year-old female from Sichuan Province with an onset date of 13 December 2024 and had pneumonia. The case had exposure to back yard poultry. The case was recovered. The second case was a two-year-old male from Hunan Province who developed symptoms on 27 December 2024. The patient had been exposed to backyard poultry. Avian Influenza Weekly Update Number 986| 3 The third case was a 15-year-old male from Hunan Province who developed symptoms on 8 January 2025. The case had exposure at a live poultry market The fourth case was a 56-year-old female from Guangdong Province who developed symptoms on 20 January 2025. The case was exposed at a live poultry market. No family clusters were reported among the four cases, and there was no epidemiological link between them. Since December 2015, a total of 117 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 114 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. Human infection with avian influenza A(H10N3) virus From 14 to 20 February 2025, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 12 December 2024. To date, four cases of human infection with avian influenza A(H10N3) have been reported globally. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 14 to 20 February 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus From 14 to 20 February 2025, there was one outbreak report of highly pathogenic avian influenza among wild birds in Cambodia reported to the World Organization for Animal Health (WOAH): • On 17 February 2025, one new outbreak of highly pathogenic avian influenza virus H5N1 was reported in wild birds in Prey Veng Province, Cambodia. The start date of the outbreaks ranged from 27 January 2025. There were 14 deaths (Source). For more information on animal infection with avian influenza viruses with potential public health impact, visit: Avian Influenza Weekly Update Number 986| 4 • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) • FAO Global Animal Disease Information System (EMPRES-i) Other updates • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2024 12 December 2024 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animal and people 20 December 2024 • Recommended composition of influenza virus vaccines for use in the 2024-2025 northern hemisphere influenza season 23 February 2024 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • https://cdn.who.int/media/docs/default-source/vcm-southern-hemisphere-recommendation-2025/sep- 2024-sh-recommendations_seasonal_final.pdf?sfvrsn=d06f7ccc_5&download=true • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020
Avian Influenza Weekly Update Number 979 | 1 Avian Influenza Weekly Update Number 979 3 January 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 20 December 2024 to 2 January 2025, no new case of human infection with avian influenza A(H5N1) virus was reported to WHO in the Western Pacific Region. From 1 January 2003 to 12 December 2024, a total of 261 cases of human infection with avian influenza A(H5N1) virus have been reported from five countries within the Western Pacific Region (Table 1). Of these cases, 142 were fatal, resulting in a case fatality rate (CFR) of 54%. The last cases in the Western Pacific Region were reported from Cambodia, with an onset date of 11 August 2024. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 12 December 2024), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020 2021 2022 2023 2024 Total C D C D C D C D C D C D C D C D C D Australia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 Cambodia 9 7 47 30 0 0 0 0 0 0 0 0 6 4 10 2 72 43 China 38 25 9 5 6 1 0 0 0 0 1 1 1 0 1 0 56 32 Lao PDR 2 2 0 0 0 0 1 0 0 0 0 0 0 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 0 0 0 0 1 0 0 0 1 1 129 65 Total 161 91 71 42 6 1 1 0 0 0 2 1 7 4 13 3 261 142 NB: This table is updated following updates from the source. Globally, from 1 January 2003 to 12 December 2024, 954 cases of human infection with avian influenza A(H5N1) virus were reported from 24 countries. Of these 954 cases, 464 were fatal (CFR of 49%). Human infection with avian influenza A(H5N6) virus From 20 December 2024 to 2 January 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 20 December 2024 to 2 January 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Avian Influenza Weekly Update Number 979 | 2 Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people. (published on 20 December 2024) Human infection with avian influenza A(H3N8) virus From 20 December 2024 to 2 January 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 20 December 2024 to 2 January 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 20 December 2024 to 2 January 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Of the 1 568 human infections with avian influenza A(H7N9), 33 have reported mutations in the hemagglutinin gene indicating a change to high pathogenicity in poultry. These 33 cases were from Taiwan, China (one case had a travel history to Guangdong), Guangxi, Guangdong, Hunan, Shaanxi, Hebei, Henan, Fujian, Yunnan, and Inner Mongolia. No increased transmissibility or virulence of the virus within human cases related to the HPAI A(H7N9) virus has been detected. Avian Influenza Weekly Update Number 979 | 3 Human infection with avian influenza A(H9N2) virus From 20 December 2024 to 2 January 2025, no new case of human infection with avian influenza A(H9N2) virus was reported in the Western Pacific Region. Since December 2015, a total of 113 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 110 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. The last two cases were reported from Guizhou Province and Guangxi Province, China, with onset dates of 28 October 2024 and 18 November 2024, respectively. Human infection with avian influenza A(H10N3) virus From 20 December 2024 to 2 January 2025, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. To date, three cases of avian influenza A(H10N3) virus have been reported globally. The last case was reported from Yunnan Province, China, with an onset date of 28 February 2024. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 20 December 2024 to 2 January 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus Between 20 December 2024 to 2 January 2025, no outbreak reports of highly pathogenic avian influenza among domestic birds were reported to the World Organization for Animal Health (WOAH). For more information on animal infection with avian influenza viruses with potential public health impact, visit: • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) • FAO Global Animal Disease Information System (EMPRES-i) Avian Influenza Weekly Update Number 979 | 4 Other updates • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003- 2024 12 December 2024 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people 20 December 2024 • Joint FAO/WHO/WOAH preliminary assessment of recent influenza A(H5N1) viruses 14 August 2024 • Recommended composition of influenza virus vaccines for use in the 2024-2025 northern hemisphere influenza season 23 February 2024 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020
Avian Influenza Weekly Update Number 980 | 1 Avian Influenza Weekly Update Number 980 10 January 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 3 January 2025 to 9 January 2025, no new case of human infection with avian influenza A(H5N1) virus was reported to WHO in the Western Pacific Region. From 1 January 2003 to 12 December 2024, a total of 261 cases of human infection with avian influenza A(H5N1) virus have been reported from five countries within the Western Pacific Region (Table 1). Of these cases, 142 were fatal, resulting in a case fatality rate (CFR) of 54%. The last cases in the Western Pacific Region were reported from Cambodia, with an onset date of 11 August 2024. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 12 December 2024), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020 2021 2022 2023 2024 Total C D C D C D C D C D C D C D C D C D Australia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 Cambodia 9 7 47 30 0 0 0 0 0 0 0 0 6 4 10 2 72 43 China 38 25 9 5 6 1 0 0 0 0 1 1 1 0 1 0 56 32 Lao PDR 2 2 0 0 0 0 1 0 0 0 0 0 0 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 0 0 0 0 1 0 0 0 1 1 129 65 Total 161 91 71 42 6 1 1 0 0 0 2 1 7 4 13 3 261 142 NB: This table is updated following updates from the source. Globally, from 1 January 2003 to 12 December 2024, 954 cases of human infection with avian influenza A(H5N1) virus were reported from 24 countries. Of these 954 cases, 464 were fatal (CFR of 49%). Human infection with avian influenza A(H5N6) virus From 3 January 2025 to 9 January 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 3 January 2025 to 9 January 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Avian Influenza Weekly Update Number 980 | 2 Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people. (published on 20 December 2024) Human infection with avian influenza A(H3N8) virus From 3 January 2025 to 9 January 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 3 January 2025 to 9 January 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 3 January 2025 to 9 January 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Of the 1 568 human infections with avian influenza A(H7N9), 33 have reported mutations in the hemagglutinin gene indicating a change to high pathogenicity in poultry. These 33 cases were from Taiwan, China (one case had a travel history to Guangdong), Guangxi, Guangdong, Hunan, Shaanxi, Hebei, Henan, Fujian, Yunnan, and Inner Mongolia. No increased transmissibility or virulence of the virus within human cases related to the HPAI A(H7N9) virus has been detected. Avian Influenza Weekly Update Number 980 | 3 Human infection with avian influenza A(H9N2) virus From 3 January 2025 to 9 January 2025, no new case of human infection with avian influenza A(H9N2) virus was reported in the Western Pacific Region. Since December 2015, a total of 113 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 110 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. The last two cases were reported from Guizhou Province and Guangxi Province, China, with onset dates of 28 October 2024 and 18 November 2024, respectively. Human infection with avian influenza A(H10N3) virus From 3 January 2025 to 9 January 2025, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. To date, three cases of avian influenza A(H10N3) virus have been reported globally. The last case was reported from Yunnan Province, China, with an onset date of 28 February 2024. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 3 January 2025 to 9 January 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus Between 3 January 2025 to 9 January 2025, there was one outbreak report of highly pathogenic avian influenza among domestic birds reported to the World Organization for Animal Health (WOAH). On 7 January 2025 the first outbreak of highly pathogenic avian influenza virus H5N2 was reported in the Philippines of which there were 15 cases, 428 susceptible birds were killed and disposed of. The outbreak began on 19 November 2024 and was confirmed on 6 December 2024. Cases were identified in backyard ducks in n the Camarines Norte province. Source Avian Influenza Weekly Update Number 980 | 4 For more information on animal infection with avian influenza viruses with potential public health impact, visit: • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) • FAO Global Animal Disease Information System (EMPRES-i) Other updates • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003- 2024 1 November 2024 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animal and people 20 December 2024 • Recommended composition of influenza virus vaccines for use in the 2024-2025 northern hemisphere influenza season 23 February 2024 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020
Avian Influenza Weekly Update Number 981 | 1 Avian Influenza Weekly Update Number 981 17 January 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 10 to 16 January 2025, one new case of human infection with avian influenza A(H5N1) virus was reported to WHO in the Western Pacific Region. The case is a 28-year-old male from Kampong Cham Province, Cambodia, with onset of symptoms on 1 January 2025. The case had exposure to poultry at a farm where he worked as a guard; There were reports of sick poultry in the farm. He was hospitalised on 7 January and passed away on 10 January 2025. From 1 January 2003 to 12 December 2024, a total of 261 cases of human infection with avian influenza A(H5N1) virus have been reported from five countries within the Western Pacific Region (Table 1). Of these cases, 142 were fatal, resulting in a case fatality rate (CFR) of 54%. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 12 December 2024), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020 2021 2022 2023 2024 Total C D C D C D C D C D C D C D C D C D Australia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 Cambodia 9 7 47 30 0 0 0 0 0 0 0 0 6 4 10 2 72 43 China 38 25 9 5 6 1 0 0 0 0 1 1 1 0 1 0 56 32 Lao PDR 2 2 0 0 0 0 1 0 0 0 0 0 0 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 0 0 0 0 1 0 0 0 1 1 129 65 Total 161 91 71 42 6 1 1 0 0 0 2 1 7 4 13 3 261 142 NB: This table is updated following updates from the source. Globally, from 1 January 2003 to 12 December 2024, 954 cases of human infection with avian influenza A(H5N1) virus were reported from 24 countries. Of these 954 cases, 464 were fatal (CFR of 49%). Human infection with avian influenza A(H5N6) virus From 10 to 16 January 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 10 to 16 January 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Avian Influenza Weekly Update Number 981 | 2 Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people, published on 20 December 2024. Human infection with avian influenza A(H3N8) virus From 10 to 16 January 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 10 to 16 January 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 10 to 16 January 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Of the 1 568 human infections with avian influenza A(H7N9), 33 have reported mutations in the hemagglutinin gene indicating a change to high pathogenicity in poultry. These 33 cases were from Taiwan, China (one case had a travel history to Guangdong), Guangxi, Guangdong, Hunan, Shaanxi, Hebei, Henan, Fujian, Yunnan, and Inner Mongolia. No increased transmissibility or virulence of the virus within human cases related to the HPAI A(H7N9) virus has been detected. Human infection with avian influenza A(H9N2) virus From 10 to 16 January 2025, two new cases of human infection with avian influenza A(H9N2) virus were reported in the Western Pacific Region. The first case is an eight-year-old female from Shiyan City, Hubei Avian Influenza Weekly Update Number 981 | 3 Province, China, with onset of symptoms on 27 November 2024. The case had exposure to poultry at a live poultry market, and her family member purchased a live chicken which was slaughtered at the stall. The second case is a one-year-old female from Chongqing City, a provincial municipality in southwest China. She had an onset of symptoms on 13 December 2024 and was hopitalised on the next day. Both cases presented mild symptoms only and have recovered. Since December 2015, a total of 115 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 112 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. Human infection with avian influenza A(H10N3) virus From 10 to 16 January 2025, one new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The case is a 23-year-old female from Nanning city, Guangxi Zhuang Autonomous Region, China, with onset of illness on 12 December 2024. The case was admitted to hospital on 19 December 2024 with severe pneumonia. She was reported to have an underlying condition and was initially in critical condition; she was still hospitalised at the time of reporting, but her condition has improved. She had exposure to fresh slaughtered poultry at part of her work at a supermarket. No additional cases have been reported from her contacts. To date, four cases of human infection with avian influenza A(H10N3), including the latest case, have been reported globally. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 10 to 16 January 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus From 10 to 16 January 2025, there were ten outbreak reports of highly pathogenic avian influenza among domestic birds, reported to the World Organization for Animal Health (WOAH): five in Taiwan, China, and five in Japan. • Taiwan, China: On 13 January 2025, five new outbreaks of highly pathogenic avian influenza virus H5N1 were reported in Taipei and Tainan, involving four domestic chicken farms and one Avian Influenza Weekly Update Number 981 | 4 slaughterhouse, with a total of 23 924 new cases, 23 896 new deaths, and 51 856 birds killed and disposed of (Source). • Japan: On 10 January 2025, five new outbreaks of highly pathogenic avian influenza virus H5N1 were reported in domestic poultry farms in Aichi, Iwate and Ibaraki prefectures, with a total of 528 new cases, 528 new deaths, and 1 390 586 birds killed and disposed of (Source). For more information on animal infection with avian influenza viruses with potential public health impact, visit: • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) • FAO Global Animal Disease Information System (EMPRES-i) Other updates • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003- 2024 1 November 2024 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animal and people 20 December 2024 • Recommended composition of influenza virus vaccines for use in the 2024-2025 northern hemisphere influenza season 23 February 2024 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020
Avian Influenza Weekly Update Number 980| 1 Avian Influenza Weekly Update Number 982 24 January 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 17 to 23 January 2025, no new case of human infection with avian influenza A(H5N1) virus was reported to WHO in the Western Pacific Region. The last case was reported from Cambodia with an onset date of 1 January 2025. From 1 January 2003 to 12 December 2024, a total of 261 cases of human infection with avian influenza A(H5N1) virus have been reported from five countries within the Western Pacific Region (Table 1). Of these cases, 142 were fatal, resulting in a case fatality rate (CFR) of 54%. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 12 December 2024), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020 2021 2022 2023 2024 Total C D C D C D C D C D C D C D C D C D Australia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 Cambodia 9 7 47 30 0 0 0 0 0 0 0 0 6 4 10 2 72 43 China 38 25 9 5 6 1 0 0 0 0 1 1 1 0 1 0 56 32 Lao PDR 2 2 0 0 0 0 1 0 0 0 0 0 0 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 0 0 0 0 1 0 0 0 1 1 129 65 Total 161 91 71 42 6 1 1 0 0 0 2 1 7 4 13 3 261 142 NB: This table is updated following updates from the source. Globally, from 1 January 2003 to 12 December 2024, 954 cases of human infection with avian influenza A(H5N1) virus were reported from 24 countries. Of these 954 cases, 464 were fatal (CFR of 49%). Human infection with avian influenza A(H5N6) virus From 17 to 23 January 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 17 to 23 January 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. Avian Influenza Weekly Update Number 980| 2 No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people, published on 20 December 2024. Human infection with avian influenza A(H3N8) virus From 17 to 23 January 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 17 to 32 January 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 17 to 23 January 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Of the 1 568 human infections with avian influenza A(H7N9), 33 have reported mutations in the hemagglutinin gene indicating a change to high pathogenicity in poultry. These 33 cases were from Taiwan, China (one case had a travel history to Guangdong), Guangxi, Guangdong, Hunan, Shaanxi, Hebei, Henan, Fujian, Yunnan, and Inner Mongolia. No increased transmissibility or virulence of the virus within human cases related to the HPAI A(H7N9) virus has been detected. Human infection with avian influenza A(H9N2) virus From 17 to 23 January 2025, no new case of human infection with avian influenza A(H9N2) virus was reported in the Western Pacific Region. The last case was reported from China with an onset date of 13 December 2024. Since December 2015, a total of 115 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 112 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. Avian Influenza Weekly Update Number 980| 3 Human infection with avian influenza A(H10N3) virus From 17 to 23 January 2025, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 12 December 2024. To date, four cases of human infection with avian influenza A(H10N3) have been reported globally. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 17 to 23 January 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus From 17 to 23 January 2025, there were five outbreak reports of highly pathogenic avian influenza among domestic birds in Japan, reported to the World Organization for Animal Health (WOAH): • On 17 January 2025, five new outbreaks of highly pathogenic avian influenza virus H5N1 were reported in domestic poultry farms in Aichi, Kagoshima and Miyazaki prefectures, with a total of 592 new cases, 592 new deaths, and 454 263 birds killed and disposed of (Source). For more information on animal infection with avian influenza viruses with potential public health impact, visit: • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) • FAO Global Animal Disease Information System (EMPRES-i) Other updates • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003- 2024 12 December 2024 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animal and people 20 December 2024 Avian Influenza Weekly Update Number 980| 4 • Recommended composition of influenza virus vaccines for use in the 2024-2025 northern hemisphere influenza season 23 February 2024 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020
Avian Influenza Weekly Update Number 983| 1 Avian Influenza Weekly Update Number 983 31 January 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 24 to 30 January 2025, no new case of human infection with avian influenza A(H5N1) virus was reported to WHO in the Western Pacific Region. The last case was reported from Cambodia with an onset date of 1 January 2025. From 1 January 2003 to 12 December 2024, a total of 261 cases of human infection with avian influenza A(H5N1) virus have been reported from five countries within the Western Pacific Region (Table 1). Of these cases, 142 were fatal, resulting in a case fatality rate (CFR) of 54%. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 12 December 2024), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020 2021 2022 2023 2024 Total C D C D C D C D C D C D C D C D C D Australia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 Cambodia 9 7 47 30 0 0 0 0 0 0 0 0 6 4 10 2 72 43 China 38 25 9 5 6 1 0 0 0 0 1 1 1 0 1 0 56 32 Lao PDR 2 2 0 0 0 0 1 0 0 0 0 0 0 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 0 0 0 0 1 0 0 0 1 1 129 65 Total 161 91 71 42 6 1 1 0 0 0 2 1 7 4 13 3 261 142 NB: This table is updated following updates from the source. Globally, from 1 January 2003 to 12 December 2024, 954 cases of human infection with avian influenza A(H5N1) virus were reported from 24 countries. Of these 954 cases, 464 were fatal (CFR of 49%). Human infection with avian influenza A(H5N6) virus From 24 to 30 January 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 24 to 30 January 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. Avian Influenza Weekly Update Number 983| 2 No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people, published on 20 December 2024. Human infection with avian influenza A(H3N8) virus From 24 to 30 January 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 24 to 30 January 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 24 to 30 January 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Of the 1 568 human infections with avian influenza A(H7N9), 33 have reported mutations in the hemagglutinin gene indicating a change to high pathogenicity in poultry. These 33 cases were from Taiwan, China (one case had a travel history to Guangdong), Guangxi, Guangdong, Hunan, Shaanxi, Hebei, Henan, Fujian, Yunnan, and Inner Mongolia. No increased transmissibility or virulence of the virus within human cases related to the HPAI A(H7N9) virus has been detected. Human infection with avian influenza A(H9N2) virus From 24 to 30 January 2025, no new case of human infection with avian influenza A(H9N2) virus was reported in the Western Pacific Region. The last case was reported from China with an onset date of 13 December 2024. Since December 2015, a total of 115 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 112 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. Avian Influenza Weekly Update Number 983| 3 Human infection with avian influenza A(H10N3) virus From 24 to 30 January 2025, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 12 December 2024. To date, four cases of human infection with avian influenza A(H10N3) have been reported globally. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 24 to 30 January 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus From 24 to 30 January 2025, there were sixteen outbreak reports of highly pathogenic avian influenza among domestic chickens/birds in Cambodia and Japan, reported to the World Organization for Animal Health (WOAH): • On 29 January 2025, one new outbreak of highly pathogenic avian influenza virus H5N1 was reported in domestic poultry farm in Preak Thom Village, Sangkat Kbal Koh, Khan Chba Ampao, Phnom Penh. The outbreak began on 18 January 2025, with a total of 153 cases and deaths, in 431 susceptible birds of which 281 were killed and disposed of (Source). • On 27 January 2025, fifteen new outbreaks of highly pathogenic avian influenza virus H5N1 were reported in domestic poultry farms in Agui, Asahi, Choshi, Handa, Morioka and Tokoname prefectures. Start date of the outbreaks ranged from 10 January to 21 January 2025. There was a total of 794 834 susceptible birds, 788 new cases, 783 new deaths, and 794 598 birds killed and disposed of (Source). For more information on animal infection with avian influenza viruses with potential public health impact, visit: • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) • FAO Global Animal Disease Information System (EMPRES-i) Avian Influenza Weekly Update Number 983| 4 Other updates • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2024 12 December 2024 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animal and people 20 December 2024 • Recommended composition of influenza virus vaccines for use in the 2024-2025 northern hemisphere influenza season 23 February 2024 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020
Avian Influenza Weekly Update Number 984| 1 Avian Influenza Weekly Update Number 984 7 February 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 31 January to 6 February 2025, no new case of human infection with avian influenza A(H5N1) virus was reported to WHO in the Western Pacific Region. The last case was reported from Cambodia with an onset date of 1 January 2025. From 1 January 2003 to 12 December 2024, a total of 261 cases of human infection with avian influenza A(H5N1) virus have been reported from five countries within the Western Pacific Region (Table 1). Of these cases, 142 were fatal, resulting in a case fatality rate (CFR) of 54%. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 12 December 2024), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020 2021 2022 2023 2024 Total C D C D C D C D C D C D C D C D C D Australia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 Cambodia 9 7 47 30 0 0 0 0 0 0 0 0 6 4 10 2 72 43 China 38 25 9 5 6 1 0 0 0 0 1 1 1 0 1 0 56 32 Lao PDR 2 2 0 0 0 0 1 0 0 0 0 0 0 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 0 0 0 0 1 0 0 0 1 1 129 65 Total 161 91 71 42 6 1 1 0 0 0 2 1 7 4 13 3 261 142 NB: This table is updated following updates from the source. Globally, from 1 January 2003 to 12 December 2024, 954 cases of human infection with avian influenza A(H5N1) virus were reported from 24 countries. Of these 954 cases, 464 were fatal (CFR of 49%). Human infection with avian influenza A(H5N6) virus From 31 January to 6 February 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 31 January to 6 February 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. Avian Influenza Weekly Update Number 984| 2 No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people, published on 20 December 2024. Human infection with avian influenza A(H3N8) virus From 31 January to 6 February 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 31 January to 6 February 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 31 January to 6 February 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Of the 1 568 human infections with avian influenza A(H7N9), 33 have reported mutations in the hemagglutinin gene indicating a change to high pathogenicity in poultry. These 33 cases were from Taiwan, China (one case had a travel history to Guangdong), Guangxi, Guangdong, Hunan, Shaanxi, Hebei, Henan, Fujian, Yunnan, and Inner Mongolia. No increased transmissibility or virulence of the virus within human cases related to the HPAI A(H7N9) virus has been detected. Human infection with avian influenza A(H9N2) virus From 31 January to 6 February 2025, no new case of human infection with avian influenza A(H9N2) virus was reported in the Western Pacific Region. The last case was reported from China with an onset date of 13 December 2024. Since December 2015, a total of 115 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 112 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. Avian Influenza Weekly Update Number 984| 3 Human infection with avian influenza A(H10N3) virus From 31 January to 6 February 2025, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 12 December 2024. To date, four cases of human infection with avian influenza A(H10N3) have been reported globally. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 31 January to 6 February 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus From 31 January to 6 February 2025, there were twenty outbreak reports of highly pathogenic avian influenza among domestic birds and wildlife species in Korea and Japan, reported to the World Organization for Animal Health (WOAH): • On 4 February 2025, three new outbreaks of highly pathogenic avian influenza virus H5N1 were reported in domestic poultry farms in Chiba and Iwate prefectures in Japan. Start date of the outbreaks ranged from 21 January to 23 January 2025. There was a total of 68 new cases, and 65 new deaths (Source). • On 4 February 2025, three new outbreaks of highly pathogenic avian influenza virus H5 (N untyped) in wild hooded cranes in Izumi-city in Japan. The outbreak began on 2 December 2024, with a total of 3 cases and deaths (Source). • On 31 January 2025, eight new outbreaks of highly pathogenic avian influenza virus H5N1 were reported in domestic poultry farms in Chungcheongbuk-do, Chungcheongnam-do, Jeollanam-do, Jeonbuk-do, Gyeonggi-do, Gyeongsangnam-do, in Republic of Korea. Start date of the outbreaks ranged from 3 January to 17 January 2025. There was a total of 252 800 susceptible birds, in which 490 new cases, 340 new deaths and 252 460 birds killed and disposed of (Source). • On 31 January 2025, six new outbreaks of highly pathogenic avian influenza virus H5N1 were reported in wild animals including Cinereous Vulture, Great Egret, Herring Gull and Wildlife (species unspecified) in Chungcheongnam-do, Gyeonggi-do, Jeju-do, in Republic of Korea. Start date of the outbreaks ranged from 27 December 2024 to 14 January 2025. There was a total of 9 new cases and 8 new deaths (Source). Avian Influenza Weekly Update Number 984| 4 For more information on animal infection with avian influenza viruses with potential public health impact, visit: • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) • FAO Global Animal Disease Information System (EMPRES-i) Other updates • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2024 12 December 2024 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animal and people 20 December 2024 • Recommended composition of influenza virus vaccines for use in the 2024-2025 northern hemisphere influenza season 23 February 2024 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020
Avian Influenza Weekly Update Number 985| 1 Avian Influenza Weekly Update Number 985 14 February 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 7 to 13 February 2025, no new case of human infection with avian influenza A(H5N1) virus was reported to WHO in the Western Pacific Region. The last case was reported from Cambodia with an onset date of 1 January 2025. From 1 January 2003 to 12 December 2024, a total of 261 cases of human infection with avian influenza A(H5N1) virus have been reported from five countries within the Western Pacific Region (Table 1). Of these cases, 142 were fatal, resulting in a case fatality rate (CFR) of 54%. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 12 December 2024), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020 2021 2022 2023 2024 Total C D C D C D C D C D C D C D C D C D Australia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 Cambodia 9 7 47 30 0 0 0 0 0 0 0 0 6 4 10 2 72 43 China 38 25 9 5 6 1 0 0 0 0 1 1 1 0 1 0 56 32 Lao PDR 2 2 0 0 0 0 1 0 0 0 0 0 0 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 0 0 0 0 1 0 0 0 1 1 129 65 Total 161 91 71 42 6 1 1 0 0 0 2 1 7 4 13 3 261 142 NB: This table is updated following updates from the source. Globally, from 1 January 2003 to 12 December 2024, 954 cases of human infection with avian influenza A(H5N1) virus were reported from 24 countries. Of these 954 cases, 464 were fatal (CFR of 49%). Human infection with avian influenza A(H5N6) virus From 7 to 13 February 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 7 to 13 February 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. Avian Influenza Weekly Update Number 985| 2 No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people, published on 20 December 2024. Human infection with avian influenza A(H3N8) virus From 7 to 13 February 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 7 to 13 February 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 7 to 13 February 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Of the 1 568 human infections with avian influenza A(H7N9), 33 have reported mutations in the hemagglutinin gene indicating a change to high pathogenicity in poultry. These 33 cases were from Taiwan, China (one case had a travel history to Guangdong), Guangxi, Guangdong, Hunan, Shaanxi, Hebei, Henan, Fujian, Yunnan, and Inner Mongolia. No increased transmissibility or virulence of the virus within human cases related to the HPAI A(H7N9) virus has been detected. Human infection with avian influenza A(H9N2) virus From 7 to 13 February 2025, no new case of human infection with avian influenza A(H9N2) virus was reported in the Western Pacific Region. The last case was reported from China with an onset date of 13 December 2024. Since December 2015, a total of 115 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 112 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. Avian Influenza Weekly Update Number 985| 3 Human infection with avian influenza A(H10N3) virus From 7 to 13 February 2025, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 12 December 2024. To date, four cases of human infection with avian influenza A(H10N3) have been reported globally. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 7 to 13 February 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus From 7 to 13 February 2025, there were fourteen outbreak reports of highly pathogenic avian influenza among domestic birds in Korea and Japan, reported to the World Organization for Animal Health (WOAH): • On 10 February 2025, eight new outbreaks of highly pathogenic avian influenza virus H5N1 were reported in domestic poultry farms in Asahi-city, Choshi-city, Handa-city, and Sosa-city, in Japan. Start date of the outbreaks ranged from 27 to 31 January 2025. There was a total of 1 245 368 susceptible birds, in which 355 new cases and deaths and 1 245 013 birds killed and disposed of (Source). • On 10 February 2025, six new outbreaks of highly pathogenic avian influenza virus H5N1 were reported in domestic poultry farms in Chungcheongbuk-do, Jeollanam-do, Jeonbuk-do, Gyeongsangbuk-do, in Republic of Korea. Start date of the outbreaks ranged from 21 January to 4 February 2025. There was a total of 240 300 susceptible birds, in which 400 new cases, 331 new deaths and 239 969 birds killed and disposed of (Source). For more information on animal infection with avian influenza viruses with potential public health impact, visit: • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) • FAO Global Animal Disease Information System (EMPRES-i) Avian Influenza Weekly Update Number 985| 4 Other updates • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2024 12 December 2024 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animal and people 20 December 2024 • Recommended composition of influenza virus vaccines for use in the 2024-2025 northern hemisphere influenza season 23 February 2024 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020
Avian Influenza Weekly Update Number 986| 1 Avian Influenza Weekly Update Number 986 21 February 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 14 to 20 February 2025, no new cases of human infection with avian influenza A(H9N2) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 13 December 2024. From 1 January 2003 to 12 December 2024, a total of 261 cases of human infection with avian influenza A(H5N1) virus have been reported from five countries within the Western Pacific Region (Table 1). Of these cases, 142 were fatal, resulting in a case fatality rate (CFR) of 54%. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 12 December 2024), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020 2021 2022 2023 2024 Total C D C D C D C D C D C D C D C D C D Australia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 Cambodia 9 7 47 30 0 0 0 0 0 0 0 0 6 4 10 2 72 43 China 38 25 9 5 6 1 0 0 0 0 1 1 1 0 1 0 56 32 Lao PDR 2 2 0 0 0 0 1 0 0 0 0 0 0 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 0 0 0 0 1 0 0 0 1 1 129 65 Total 161 91 71 42 6 1 1 0 0 0 2 1 7 4 13 3 261 142 NB: This table is updated following updates from the source. Globally, from 1 January 2003 to 12 December 2024, 954 cases of human infection with avian influenza A(H5N1) virus were reported from 24 countries. Of these 954 cases, 464 were fatal (CFR of 49%). Human infection with avian influenza A(H5N6) virus From 14 to 20 February 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 14 to 20 February 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. Avian Influenza Weekly Update Number 986| 2 No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people, published on 20 December 2024. Human infection with avian influenza A(H3N8) virus From 14 to 20 February 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 14 to 20 February 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 14 to 20 February 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Of the 1 568 human infections with avian influenza A(H7N9), 33 have reported mutations in the hemagglutinin gene indicating a change to high pathogenicity in poultry. These 33 cases were from Taiwan, China (one case had a travel history to Guangdong), Guangxi, Guangdong, Hunan, Shaanxi, Hebei, Henan, Fujian, Yunnan, and Inner Mongolia. No increased transmissibility or virulence of the virus within human cases related to the HPAI A(H7N9) virus has been detected. Human infection with avian influenza A(H9N2) virus From 14 to 20 February 2025, four new cases of human infection with avian influenza A(H9N2) virus were reported from China in the Western Pacific Region. The first case was a 72-year-old female from Sichuan Province with an onset date of 13 December 2024 and had pneumonia. The case had exposure to back yard poultry. The case was recovered. The second case was a two-year-old male from Hunan Province who developed symptoms on 27 December 2024. The patient had been exposed to backyard poultry. Avian Influenza Weekly Update Number 986| 3 The third case was a 15-year-old male from Hunan Province who developed symptoms on 8 January 2025. The case had exposure at a live poultry market The fourth case was a 56-year-old female from Guangdong Province who developed symptoms on 20 January 2025. The case was exposed at a live poultry market. No family clusters were reported among the four cases, and there was no epidemiological link between them. Since December 2015, a total of 117 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 114 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. Human infection with avian influenza A(H10N3) virus From 14 to 20 February 2025, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 12 December 2024. To date, four cases of human infection with avian influenza A(H10N3) have been reported globally. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 14 to 20 February 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus From 14 to 20 February 2025, there was one outbreak report of highly pathogenic avian influenza among wild birds in Cambodia reported to the World Organization for Animal Health (WOAH): • On 17 February 2025, one new outbreak of highly pathogenic avian influenza virus H5N1 was reported in wild birds in Prey Veng Province, Cambodia. The start date of the outbreaks ranged from 27 January 2025. There were 14 deaths (Source). For more information on animal infection with avian influenza viruses with potential public health impact, visit: Avian Influenza Weekly Update Number 986| 4 • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) • FAO Global Animal Disease Information System (EMPRES-i) Other updates • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2024 12 December 2024 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animal and people 20 December 2024 • Recommended composition of influenza virus vaccines for use in the 2024-2025 northern hemisphere influenza season 23 February 2024 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • https://cdn.who.int/media/docs/default-source/vcm-southern-hemisphere-recommendation-2025/sep- 2024-sh-recommendations_seasonal_final.pdf?sfvrsn=d06f7ccc_5&download=true • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020
Avian Influenza Weekly Update Number 987| 1 Avian Influenza Weekly Update Number 987 28 February 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 21 to 27 February 2025, no new case of human infection with avian influenza A(H5N1) virus was reported to WHO in the Western Pacific Region. The last case was reported from Cambodia with an onset date of 1 January 2025. From 1 January 2003 to 20 January 2025, a total of 262 cases of human infection with avian influenza A(H5N1) virus have been reported from five countries within the Western Pacific Region (Table 1). Of these cases, 143 were fatal, resulting in a case fatality rate (CFR) of 55%. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 20 January 2025), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020-2024 2025 Total C D C D C D C D C D C D Australia 0 0 0 0 0 0 1 0 0 0 1 0 Cambodia 9 7 47 30 0 0 16 6 1 1 73 44 China 38 25 9 5 6 1 3 1 0 0 56 32 Lao PDR 2 2 0 0 0 0 1 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 2 1 0 0 129 65 Total 161 91 71 42 6 1 23 8 1 1 262 143 NB: This table is updated following updates from the source. Globally, from 1 January 2003 to 20 January 2025, 964 cases of human infection with avian influenza A(H5N1) virus were reported from 24 countries. Of these 964 cases, 466 were fatal (CFR of 48%). Human infection with avian influenza A(H5N6) virus From 21 to 27 February 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 21 to 27 February 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. Avian Influenza Weekly Update Number 987| 2 No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people, published on 20 December 2024. Human infection with avian influenza A(H3N8) virus From 21 to 27 February 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 21 to 27 February 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 21 to 27 February 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Of the 1 568 human infections with avian influenza A(H7N9), 33 have reported mutations in the hemagglutinin gene indicating a change to high pathogenicity in poultry. These 33 cases were from Taiwan, China (one case had a travel history to Guangdong), Guangxi, Guangdong, Hunan, Shaanxi, Hebei, Henan, Fujian, Yunnan, and Inner Mongolia. No increased transmissibility or virulence of the virus within human cases related to the HPAI A(H7N9) virus has been detected. Human infection with avian influenza A(H9N2) virus From 21 to 27 February 2025, no new cases of human infection with avian influenza A(H9N2) virus was reported in the Western Pacific Region. The last case was reported from China with an onset date of 29 January 2025. Since December 2015, a total of 117 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 114 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. Avian Influenza Weekly Update Number 987| 3 Human infection with avian influenza A(H10N3) virus From 21 to 27 February 2025, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 12 December 2024. To date, four cases of human infection with avian influenza A(H10N3) have been reported globally. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 21 to 27 February 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus From 21 to 27 February 2025, there were 23 outbreak reports of highly pathogenic avian influenza among domestic birds and wild birds, reported to the World Organization for Animal Health (WOAH): one in Australia, nine in Republic of Korea, and 13 in Taiwan, China. • Australia: On 21 February 2025, one new outbreak of highly pathogenic avian influenza virus H7N8 was reported in domestic poultry farms in Victoria, with 25 new cases and 23 deaths and 175 185 birds killed and disposed of (Source). • Republic of Korea: On 25 February 2025, seven new outbreaks of highly pathogenic avian influenza virus H5N1 were reported in wild birds in Chungchengnam-do, Gyeonggi-do, Gyeongsangbuk-do, and Gyeongsangnam-do with a total of 9 new cases (Source). • Republic of Korea: On 25 February 2025, two new outbreaks of highly pathogenic avian influenza virus H5N1 were reported in domestic poultry farms in Jeollabok-do, with 300 new cases and 20 deaths and 101 980 birds killed and disposed of (Source). • Taiwan, China: On 21 February 2025, one new outbreak of highly pathogenic avian influenza virus H5N1 was reported in wild birds in Tainan, with a total of 1 new case and death (Source). • Taiwan, China: On 21 February 2025, 12 new outbreaks of highly pathogenic avian influenza virus H5N1 were reported in domestic poultry farms in Taipei and Tainan, with 40 953 new cases and 40 953 deaths and 301 201 birds killed and disposed of (Source). Avian Influenza Weekly Update Number 987| 4 For more information on animal infection with avian influenza viruses with potential public health impact, visit: • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) • FAO Global Animal Disease Information System (EMPRES-i) Other updates • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2025 20 January 2025 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animal and people 20 December 2024 • Recommended composition of influenza virus vaccines for use in the 2024-2025 northern hemisphere influenza season 23 February 2024 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • https://cdn.who.int/media/docs/default-source/vcm-southern-hemisphere-recommendation-2025/sep- 2024-sh-recommendations_seasonal_final.pdf?sfvrsn=d06f7ccc_5&download=true • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020
Avian Influenza Weekly Update Number 989 | 1 Avian Influenza Weekly Update Number 989 14 March 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 7 to 13 March 2025, no new case of human infection with avian influenza A(H5N1) virus was reported to WHO in the Western Pacific Region. The last case was reported from Prey Veng Province, Cambodia, with onset of symptoms on 17 February 2025. From 1 January 2003 to 20 January 2025, a total of 262 cases of human infection with avian influenza A(H5N1) virus have been reported from five countries within the Western Pacific Region (Table 1). Of these cases, 143 were fatal, resulting in a case fatality rate (CFR) of 55%. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 20 January 2025), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020-2024 2025 Total C D C D C D C D C D C D Australia 0 0 0 0 0 0 1 0 0 0 1 0 Cambodia 9 7 47 30 0 0 16 6 1 1 73 44 China 38 25 9 5 6 1 3 1 0 0 56 32 Lao PDR 2 2 0 0 0 0 1 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 2 1 0 0 129 65 Total 161 91 71 42 6 1 23 8 1 1 262 143 NB: This table is updated following updates from the source. Globally, from 1 January 2003 to 20 January 2025, 964 cases of human infection with avian influenza A(H5N1) virus were reported from 24 countries. Of these 964 cases, 466 were fatal (CFR of 48%). Human infection with avian influenza A(H5N6) virus From 7 to 13 March 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 7 to 13 March 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. Avian Influenza Weekly Update Number 988 | 2 No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people, published on 20 December 2024. Human infection with avian influenza A(H3N8) virus From 7 to 13 March 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 7 to 13 March 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 7 to 13 March 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Of the 1 568 human infections with avian influenza A(H7N9), 33 have reported mutations in the hemagglutinin gene indicating a change to high pathogenicity in poultry. These 33 cases were from Taiwan, China (one case had a travel history to Guangdong), Guangxi, Guangdong, Hunan, Shaanxi, Hebei, Henan, Fujian, Yunnan, and Inner Mongolia. No increased transmissibility or virulence of the virus within human cases related to the HPAI A(H7N9) virus has been detected. Human infection with avian influenza A(H9N2) virus From 7 to 13 March 2025, no new cases of human infection with avian influenza A(H9N2) virus was reported in the Western Pacific Region. The last case was reported from China with an onset date of 29 January 2025. Since December 2015, a total of 117 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 114 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. Avian Influenza Weekly Update Number 988 | 3 Human infection with avian influenza A(H10N3) virus From 7 to 13 March 2025, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 12 December 2024. To date, four cases of human infection with avian influenza A(H10N3) have been reported globally. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 7 to 13 February 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus From 7 to 13 March 2025, two outbreaks of highly pathogenic avian influenza were reported from Cambodia to the World Organization for Animal Health (WOAH): • On 10 March 2025, an outbreak of highly pathogenic avian influenza virus H5N1 was reported in domestic poultry in Preah Sihanouk Province, with 24 cases, 24 deaths, and 62 birds killed and disposed of (Source). • On 8 March 2025, an outbreak of highly pathogenic avian influenza virus H5N1 was reported in domestic poultry in Siem Reap Province, with 809 cases, 809 deaths, and 1 065 birds killed and disposed of (Source). For more information on animal infection with avian influenza viruses with potential public health impact, visit: • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) • FAO Global Animal Disease Information System (EMPRES-i) Avian Influenza Weekly Update Number 988 | 4 Other updates • Genetic and antigenic characteristics of zoonotic influenza A viruses and development of candidate vaccine viruses for pandemic preparedness February 2025 • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2025 20 January 2025 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animal and people 20 December 2024 • Recommended composition of influenza virus vaccines for use in the 2025-2026 northern hemisphere influenza season 28 February 2025 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020
Avian Influenza Weekly Update Number 991 | 1 Avian Influenza Weekly Update Number 991 28 March 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 21 to 27 March 2025, no new case of human infection with avian influenza A(H5N1) virus was reported to WHO in the Western Pacific Region. The last case was reported from Prey Veng Province, Cambodia, with onset of symptoms on 17 February 2025. From 1 January 2003 to 20 January 2025, a total of 262 cases of human infection with avian influenza A(H5N1) virus have been reported from five countries within the Western Pacific Region (Table 1). Of these cases, 143 were fatal, resulting in a case fatality rate (CFR) of 55%. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 20 January 2025), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020-2024 2025 Total C D C D C D C D C D C D Australia 0 0 0 0 0 0 1 0 0 0 1 0 Cambodia 9 7 47 30 0 0 16 6 1 1 73 44 China 38 25 9 5 6 1 3 1 0 0 56 32 Lao PDR 2 2 0 0 0 0 1 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 2 1 0 0 129 65 Total 161 91 71 42 6 1 23 8 1 1 262 143 NB: This table is updated following updates from the source. Globally, from 1 January 2003 to 20 January 2025, 964 cases of human infection with avian influenza A(H5N1) virus were reported from 24 countries. Of these 964 cases, 466 were fatal (CFR of 48%). Human infection with avian influenza A(H5N6) virus From 21 to 27 March 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 21 to 27 March 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. Avian Influenza Weekly Update Number 991 | 2 No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people, published on 20 December 2024. Human infection with avian influenza A(H3N8) virus From 21 to 27 March 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 21 to 27 March 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 21 to 27 March 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Of the 1 568 human infections with avian influenza A(H7N9), 33 have reported mutations in the hemagglutinin gene indicating a change to high pathogenicity in poultry. These 33 cases were from Taiwan, China (one case had a travel history to Guangdong), Guangxi, Guangdong, Hunan, Shaanxi, Hebei, Henan, Fujian, Yunnan, and Inner Mongolia. No increased transmissibility or virulence of the virus within human cases related to the HPAI A(H7N9) virus has been detected. Human infection with avian influenza A(H9N2) virus From 21 to 27 March 2025, no new case of human infection with avian influenza A(H9N2) virus was reported in the Western Pacific Region. The last case was reported from China with an onset date of 29 January 2025. Since December 2015, a total of 117 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Avian Influenza Weekly Update Number 991 | 3 Western Pacific Region. Of these, 114 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. Human infection with avian influenza A(H10N3) virus From 21 to 27 March 2025, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 12 December 2024. To date, four cases of human infection with avian influenza A(H10N3) have been reported globally. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 21 to 27 March 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus From 21 to 27 March 2025, no outbreak of highly pathogenic avian influenza in animal was reported from countries and areas in the Western Pacific Region to the World Organization for Animal Health (WOAH). For more information on animal infection with avian influenza viruses with potential public health impact, visit: • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) • FAO Global Animal Disease Information System (EMPRES-i) Other updates • Genetic and antigenic characteristics of zoonotic influenza A viruses and development of candidate vaccine viruses for pandemic preparedness February 2025 • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2025 20 January 2025 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animal and people 20 December 2024 Avian Influenza Weekly Update Number 991 | 4 • Recommended composition of influenza virus vaccines for use in the 2025-2026 northern hemisphere influenza season 28 February 2025 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020
Avian Influenza Weekly Update Number 992 | 1 Avian Influenza Weekly Update Number 992 4 April 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 28 March to 3 April 2025, one new case of human infection with avian influenza A(H5N1) virus was reported to WHO in the Western Pacific Region. The case is a 3-year-old male from Kratie Province, Cambodia, with onset of symptoms on 18 March 2025. He was hospitalized on 21 March and passed away on 23 March 2025. The case had exposure to dead chickens at his house. From 1 January 2003 to 19 March 2025, a total of 263 cases of human infection with avian influenza A(H5N1) virus have been reported from five countries within the Western Pacific Region (Table 1). Of these cases, 144 were fatal, resulting in a case fatality rate (CFR) of 54.8%. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 19 March 2025), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020-2024 2025 Total C D C D C D C D C D C D Australia 0 0 0 0 0 0 1 0 0 0 1 0 Cambodia 9 7 47 30 0 0 16 6 2 2 74 45 China 38 25 9 5 6 1 3 1 0 0 56 32 Lao PDR 2 2 0 0 0 0 1 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 2 1 0 0 129 65 Total 161 91 71 42 6 1 23 8 2 2 263 144 NB: This table is updated following updates from the source. Globally, from 1 January 2003 to 19 March 2025, 969 cases of human infection with avian influenza A(H5N1) virus were reported from 24 countries. Of these 969 cases, 467 were fatal (CFR of 48.2%). Human infection with avian influenza A(H5N6) virus From 28 March to 3 April 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 28 March to 3 April 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. Avian Influenza Weekly Update Number 992 | 2 No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people, published on 20 December 2024. Human infection with avian influenza A(H3N8) virus From 28 March to 3 April 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 28 March to 3 April 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 28 March to 3 April 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Of the 1 568 human infections with avian influenza A(H7N9), 33 have reported mutations in the hemagglutinin gene indicating a change to high pathogenicity in poultry. These 33 cases were from Taiwan, China (one case had a travel history to Guangdong), Guangxi, Guangdong, Hunan, Shaanxi, Hebei, Henan, Fujian, Yunnan, and Inner Mongolia. No increased transmissibility or virulence of the virus within human cases related to the HPAI A(H7N9) virus has been detected. Avian Influenza Weekly Update Number 992 | 3 Human infection with avian influenza A(H9N2) virus From 28 March to 3 April 2025, no new case of human infection with avian influenza A(H9N2) virus was reported in the Western Pacific Region. The last case was reported from China with an onset date of 29 January 2025. Since December 2015, a total of 117 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 114 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. Human infection with avian influenza A(H10N3) virus From 28 March to 3 April 2025, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 12 December 2024. To date, four cases of human infection with avian influenza A(H10N3) have been reported globally. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 28 March to 3 April 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus From 28 to 3 April 2025, there was one outbreak of highly pathogenic avian influenza reported from Cambodia to the World Organization for Animal Health (WOAH): • On 3 April 2025, an outbreak of highly pathogenic avian influenza virus H5N1 was reported in domestic poultry in Kracheh Province, with 20 cases, 20 deaths, and 156 birds killed and disposed of (Source). Avian Influenza Weekly Update Number 992 | 4 For more information on animal infection with avian influenza viruses with potential public health impact, visit: • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) • FAO Global Animal Disease Information System (EMPRES-i) Other updates • Genetic and antigenic characteristics of zoonotic influenza A viruses and development of candidate vaccine viruses for pandemic preparedness February 2025 • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2025 19 March 2025 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animal and people 20 December 2024 • Recommended composition of influenza virus vaccines for use in the 2025-2026 northern hemisphere influenza season 28 February 2025 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020
Avian Influenza Weekly Update Number 992| 1 Avian Influenza Weekly Update Number 993 11 April 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 4 to 10 April 2025, no new case of human infection with avian influenza A(H5N1) virus was reported to WHO in the Western Pacific Region. The last case was reported from Kratie Province, Cambodia, with onset of symptoms on 18 March 2025. From 1 January 2003 to 19 March 2025, a total of 263 cases of human infection with avian influenza A(H5N1) virus have been reported from five countries within the Western Pacific Region (Table 1). Of these cases, 144 were fatal, resulting in a case fatality rate (CFR) of 54.8%. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 19 March 2025), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020-2024 2025 Total C D C D C D C D C D C D Australia 0 0 0 0 0 0 1 0 0 0 1 0 Cambodia 9 7 47 30 0 0 16 6 2 2 74 45 China 38 25 9 5 6 1 3 1 0 0 56 32 Lao PDR 2 2 0 0 0 0 1 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 2 1 0 0 129 65 Total 161 91 71 42 6 1 23 8 2 2 263 144 NB: This table is updated following updates from the source. Globally, from 1 January 2003 to 19 March 2025, 969 cases of human infection with avian influenza A(H5N1) virus were reported from 24 countries. Of these 969 cases, 467 were fatal (CFR of 48.2%). Human infection with avian influenza A(H5N6) virus From 4 to 10 April 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 4 to 10 April 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. Avian Influenza Weekly Update Number 992| 2 No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people, published on 20 December 2024. Human infection with avian influenza A(H3N8) virus From 4 to 10 April 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 4 to 10 April 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 4 to 10 April 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Of the 1 568 human infections with avian influenza A(H7N9), 33 have reported mutations in the hemagglutinin gene indicating a change to high pathogenicity in poultry. These 33 cases were from Taiwan, China (one case had a travel history to Guangdong), Guangxi, Guangdong, Hunan, Shaanxi, Hebei, Henan, Fujian, Yunnan, and Inner Mongolia. No increased transmissibility or virulence of the virus within human cases related to the HPAI A(H7N9) virus has been detected. Human infection with avian influenza A(H9N2) virus From 4 to 10 April 2025, no new case of human infection with avian influenza A(H9N2) virus was reported in the Western Pacific Region. The last case was reported from China with an onset date of 29 January 2025. Since December 2015, a total of 117 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 114 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. Avian Influenza Weekly Update Number 992| 3 Human infection with avian influenza A(H10N3) virus From 4 to 10 April 2025, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 12 December 2024. To date, four cases of human infection with avian influenza A(H10N3) have been reported globally. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 4 to 10 April 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus From 4 to 10 April 2025, no outbreak of highly pathogenic avian influenza in animal was reported from countries and areas in the Western Pacific Region to the World Organization for Animal Health (WOAH). For more information on animal infection with avian influenza viruses with potential public health impact, visit: • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) • FAO Global Animal Disease Information System (EMPRES-i) Other updates • Genetic and antigenic characteristics of zoonotic influenza A viruses and development of candidate vaccine viruses for pandemic preparedness February 2025 • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2025 19 March 2025 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animal and people 20 December 2024 • Recommended composition of influenza virus vaccines for use in the 2025-2026 northern hemisphere influenza season 28 February 2025 Avian Influenza Weekly Update Number 992| 4 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020
Avian Influenza Weekly Update Number 994 | 1 Avian Influenza Weekly Update Number 994 25 April 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 11 to 24 April 2025, no new case of human infection with avian influenza A(H5N1) virus was reported to WHO in the Western Pacific Region. The last case was reported from Kratie Province, Cambodia, with onset of symptoms on 18 March 2025. From 1 January 2003 to 19 March 2025, a total of 263 cases of human infection with avian influenza A(H5N1) virus have been reported from five countries within the Western Pacific Region (Table 1). Of these cases, 144 were fatal, resulting in a case fatality rate (CFR) of 54.8%. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 19 March 2025), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020-2024 2025 Total C D C D C D C D C D C D Australia 0 0 0 0 0 0 1 0 0 0 1 0 Cambodia 9 7 47 30 0 0 16 6 2 2 74 45 China 38 25 9 5 6 1 3 1 0 0 56 32 Lao PDR 2 2 0 0 0 0 1 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 2 1 0 0 129 65 Total 161 91 71 42 6 1 23 8 2 2 263 144 NB: This table is updated following updates from the source. Globally, from 1 January 2003 to 19 March 2025, 969 cases of human infection with avian influenza A(H5N1) virus were reported from 24 countries. Of these 969 cases, 467 were fatal (CFR of 48.2%). Human infection with avian influenza A(H5N6) virus From 11 to 24 April 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 11 to 24 April 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. Avian Influenza Weekly Update Number 994 | 2 No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people, published on 20 December 2024. Human infection with avian influenza A(H3N8) virus From 11 to 24 April 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 11 to 24 April 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 11 to 24 April 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Of the 1 568 human infections with avian influenza A(H7N9), 33 have reported mutations in the hemagglutinin gene indicating a change to high pathogenicity in poultry. These 33 cases were from Taiwan, China (one case had a travel history to Guangdong), Guangxi, Guangdong, Hunan, Shaanxi, Hebei, Henan, Fujian, Yunnan, and Inner Mongolia. No increased transmissibility or virulence of the virus within human cases related to the HPAI A(H7N9) virus has been detected. Human infection with avian influenza A(H9N2) virus From 11 to 24 April 2025, three new cases of human infection with avian influenza A(H9N2) virus were reported in the Western Pacific Region. The first case is 7-years-old female reported from Henan Province, China with an onset date of 11 February 2025. The second case is 5-years-old male reported from Guangxi Province, China with an onset date of 3 March 2025. They were presented with mild symptoms and have recovered. The third case is 35-years-old female reported from Guizhou Province, China with an onset of date of 10 March 2025 and developed severe pneumonia and was hospitalized on 13 March 2025. All three Avian Influenza Weekly Update Number 994 | 3 cases had exposure history of poultry before developing symptoms and there are no infections in other family members were reported among the three cases. Since December 2015, a total of 120 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 117 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. Human infection with avian influenza A(H10N3) virus From 11 to 24 April 2025, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 12 December 2024. To date, four cases of human infection with avian influenza A(H10N3) have been reported globally. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 11 to 24 April 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus From 11 to 24 April 2025, no outbreak of highly pathogenic avian influenza in animal was reported from countries and areas in the Western Pacific Region to the World Organization for Animal Health (WOAH). For more information on animal infection with avian influenza viruses with potential public health impact, visit: • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) • FAO Global Animal Disease Information System (EMPRES-i) Avian Influenza Weekly Update Number 994 | 4 Other updates • Genetic and antigenic characteristics of zoonotic influenza A viruses and development of candidate vaccine viruses for pandemic preparedness February 2025 • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2025 19 March 2025 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animal and people 20 December 2024 • Recommended composition of influenza virus vaccines for use in the 2025-2026 northern hemisphere influenza season 28 February 2025 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020
Avian Influenza Weekly Update Number 995 | 1 Avian Influenza Weekly Update Number 995 2 May 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 25 April to 1 May 2025, one new case of human infection with avian influenza A(H5N1) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tay Ninh Province, Viet Nam, with onset of symptoms on 11 April 2025. From 1 January 2003 to 19 March 2025, a total of 263 cases of human infection with avian influenza A(H5N1) virus have been reported from five countries within the Western Pacific Region (Table 1). Of these cases, 144 were fatal, resulting in a case fatality rate (CFR) of 54.8%. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 19 March 2025), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020-2024 2025 Total C D C D C D C D C D C D Australia 0 0 0 0 0 0 1 0 0 0 1 0 Cambodia 9 7 47 30 0 0 16 6 2 2 74 45 China 38 25 9 5 6 1 3 1 0 0 56 32 Lao PDR 2 2 0 0 0 0 1 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 2 1 0 0 129 65 Total 161 91 71 42 6 1 23 8 2 2 263 144 NB: This table is updated following updates from the source Globally, from 1 January 2003 to 19 March 2025, 969 cases of human infection with avian influenza A(H5N1) virus were reported from 24 countries. Of these 969 cases, 467 were fatal (CFR of 48.2%). Human infection with avian influenza A(H5N6) virus From 25 April to 1 May 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 25 April to 1 May 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Avian Influenza Weekly Update Number 995 | 2 Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people, published on 20 December 2024. Human infection with avian influenza A(H3N8) virus From 25 April to 1 May 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 25 April to 1 May 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 25 April to 1 May 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Of the 1 568 human infections with avian influenza A(H7N9), 33 have reported mutations in the hemagglutinin gene indicating a change to high pathogenicity in poultry. These 33 cases were from Taiwan, China (one case had a travel history to Guangdong), Guangxi, Guangdong, Hunan, Shaanxi, Hebei, Henan, Fujian, Yunnan, and Inner Mongolia. No increased transmissibility or virulence of the virus within human cases related to the HPAI A(H7N9) virus has been detected. Avian Influenza Weekly Update Number 995 | 3 Human infection with avian influenza A(H9N2) virus From 25 April to 1 May 2025, no new case of human infection with avian influenza A(H9N2) virus was reported to WHO in the Western Pacific Region. Last three new cases of human infection with avian influenza A(H9N2) virus were reported from China. Since December 2015, a total of 120 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 117 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. Human infection with avian influenza A(H10N3) virus From 25 April to 1 May 2025, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 12 December 2024. To date, four cases of human infection with avian influenza A(H10N3) have been reported globally. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 25 April to 1 May 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus From 25 April to 1 May 2025, no outbreak of highly pathogenic avian influenza in animal was reported from countries and areas in the Western Pacific Region to the World Organization for Animal Health (WOAH). For more information on animal infection with avian influenza viruses with potential public health impact, visit: • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) • FAO Global Animal Disease Information System (EMPRES-i) Avian Influenza Weekly Update Number 995 | 4 Other updates • Genetic and antigenic characteristics of zoonotic influenza A viruses and development of candidate vaccine viruses for pandemic preparedness February 2025 • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2025 19 March 2025 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animal and people 20 December 2024 • Recommended composition of influenza virus vaccines for use in the 2025-2026 northern hemisphere influenza season 28 February 2025 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020
Avian Influenza Weekly Update Number 996| 1 Avian Influenza Weekly Update Number 996 9 May 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 2 May to 8 May 2025, no new case of human infection with avian influenza A(H5N1) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tay Ninh Province, Viet Nam, with onset of symptoms on 11 April 2025. From 1 January 2003 to 22 April 2025, a total of 265 cases of human infection with avian influenza A(H5N1) virus have been reported from five countries within the Western Pacific Region (Table 1). Of these cases, 145 were fatal, resulting in a case fatality rate (CFR) of 54.7%. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 22 April 2025), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020-2024 2025 Total C D C D C D C D C D C D Australia 0 0 0 0 0 0 1 0 0 0 1 0 Cambodia 9 7 47 30 0 0 16 6 3 3 75 46 China 38 25 9 5 6 1 3 1 0 0 56 32 Lao PDR 2 2 0 0 0 0 1 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 2 1 1 0 130 65 Total 161 91 71 42 6 1 23 8 4 3 265 145 Source: Confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2025 Globally, from 1 January 2003 to 22 April 2025, 973 cases of human infection with avian influenza A(H5N1) virus were reported from 25 countries. Of these 973 cases, 470 were fatal (CFR of 48.3%). Human infection with avian influenza A(H5N6) virus From 2 May to 8 May 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 2 May to 8 May 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Avian Influenza Weekly Update Number 996| 2 Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people, published on 17 April 2025. Human infection with avian influenza A(H3N8) virus From 2 May to 8 May 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 2 May to 8 May 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 2 May to 8 May 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Avian Influenza Weekly Update Number 996| 3 Human infection with avian influenza A(H9N2) virus From 2 May to 8 May 2025, no new case of human infection with avian influenza A(H9N2) virus was reported to WHO in the Western Pacific Region. Last three new cases of human infection with avian influenza A(H9N2) virus were reported from China. Since December 2015, a total of 120 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 117 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. Human infection with avian influenza A(H10N3) virus From 2 May to 8 May 2025, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 12 December 2024. To date, four cases of human infection with avian influenza A(H10N3) have been reported globally. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 2 May to 8 May 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus From 2 May to 8 May 2025, no outbreak of highly pathogenic avian influenza in animal was reported from countries and areas in the Western Pacific Region to the World Organization for Animal Health (WOAH). For more information on animal infection with avian influenza viruses with potential public health impact, visit: • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) • FAO Global Animal Disease Information System (EMPRES-i) Avian Influenza Weekly Update Number 996| 4 Other updates • Influenza at the human-animal interface, Summary and risk assessment, from 20 March to 22 April 2025 22 April 2025 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animal and people 17 April 2025 • Genetic and antigenic characteristics of zoonotic influenza A viruses and development of candidate vaccine viruses for pandemic preparedness February 2025 • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2025 19 March 2025 • Recommended composition of influenza virus vaccines for use in the 2025-2026 northern hemisphere influenza season 28 February 2025 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020
Avian Influenza Weekly Update Number 997 | 1 Avian Influenza Weekly Update Number 997 16 May 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 9 to 15 May 2025, no new case of human infection with avian influenza A(H5N1) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tay Ninh Province, Viet Nam, with onset of symptoms on 11 April 2025. From 1 January 2003 to 22 April 2025, a total of 265 cases of human infection with avian influenza A(H5N1) virus have been reported from five countries within the Western Pacific Region (Table 1). Of these cases, 145 were fatal, resulting in a case fatality rate (CFR) of 54.7%. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 22 April 2025), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020-2024 2025 Total C D C D C D C D C D C D Australia 0 0 0 0 0 0 1 0 0 0 1 0 Cambodia 9 7 47 30 0 0 16 6 3 3 75 46 China 38 25 9 5 6 1 3 1 0 0 56 32 Lao PDR 2 2 0 0 0 0 1 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 2 1 1 0 130 65 Total 161 91 71 42 6 1 23 8 4 3 265 145 Source: Confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2025 Globally, from 1 January 2003 to 22 April 2025, 973 cases of human infection with avian influenza A(H5N1) virus were reported from 25 countries. Of these 973 cases, 470 were fatal (CFR of 48.3%). Human infection with avian influenza A(H5N6) virus From 9 to 15 May 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 9 to 15 May 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Avian Influenza Weekly Update Number 997 | 2 Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people, published on 17 April 2025. Human infection with avian influenza A(H3N8) virus From 9 to 15 May 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 9 to 15 May 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 9 to 15 May 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Avian Influenza Weekly Update Number 997 | 3 Human infection with avian influenza A(H9N2) virus From 9 to 15 May 2025, no new case of human infection with avian influenza A(H9N2) virus was reported to WHO in the Western Pacific Region. Last three new cases of human infection with avian influenza A(H9N2) virus were reported from China. Since December 2015, a total of 120 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 117 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. Human infection with avian influenza A(H10N3) virus From 9 to 15 May 2025, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 12 December 2024. To date, four cases of human infection with avian influenza A(H10N3) have been reported globally. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 9 to 15 May 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus From 9 to 15 May 2025, four outbreaks of highly pathogenic avian influenza in animal were reported from Philippines to the World Organization for Animal Health (WOAH): • On 13 May 2025, three new outbreaks of highly pathogenic avian influenza virus H5N1 were reported in domestic poultry and commercial duck farms in Pampanga Province with a total of 45 cases, 25 deaths, and 530 birds killed and disposed of (Source). • On 13 May 2025, one new outbreak of highly pathogenic avian influenza virus H5N9 was reported in domestic poultry in Camarines Sur Province, with a total of 84 cases, 84 deaths, and 26 birds killed and disposed of. The affected population are ducks grazing in a rice field situated within the province, where they may have come into contact with wild birds carrying the virus. This is the first detection of the strain in the country (Source). Avian Influenza Weekly Update Number 997 | 4 For more information on animal infection with avian influenza viruses with potential public health impact, visit: • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) • FAO Global Animal Disease Information System (EMPRES-i) Other updates • Influenza at the human-animal interface, Summary and risk assessment, from 20 March to 22 April 2025 22 April 2025 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animal and people 17 April 2025 • Genetic and antigenic characteristics of zoonotic influenza A viruses and development of candidate vaccine viruses for pandemic preparedness February 2025 • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2025 19 March 2025 • Recommended composition of influenza virus vaccines for use in the 2025-2026 northern hemisphere influenza season 28 February 2025 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020
Avian Influenza Weekly Update Number 998| 1 Avian Influenza Weekly Update Number 998 23 May 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 16 to 22 May 2025, one new case of human infection with avian influenza A(H5N1) virus was reported to WHO in the Western Pacific Region. The new case was reported from Guangxi Autonomous Region, China. The case was recovered and discharged on 11 April 2025. From 1 January 2003 to 22 April 2025, a total of 265 cases of human infection with avian influenza A(H5N1) virus have been reported from five countries within the Western Pacific Region (Table 1). Of these cases, 145 were fatal, resulting in a case fatality rate (CFR) of 54.7%. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 22 April 2025), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020-2024 2025 Total C D C D C D C D C D C D Australia 0 0 0 0 0 0 1 0 0 0 1 0 Cambodia 9 7 47 30 0 0 16 6 3 3 75 46 China 38 25 9 5 6 1 3 1 0 0 56 32 Lao PDR 2 2 0 0 0 0 1 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 2 1 1 0 130 65 Total 161 91 71 42 6 1 23 8 4 3 265 145 Source: Confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2025 Globally, from 1 January 2003 to 22 April 2025, 973 cases of human infection with avian influenza A(H5N1) virus were reported from 25 countries. Of these 973 cases, 470 were fatal (CFR of 48.3%). Human infection with avian influenza A(H5N6) virus From 16 to 22 May 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 16 to 22 May 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Avian Influenza Weekly Update Number 998| 2 Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people, published on 17 April 2025. Human infection with avian influenza A(H3N8) virus From 16 to 22 May 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 16 to 22 May 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 16 to 22 May 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Avian Influenza Weekly Update Number 998| 3 Human infection with avian influenza A(H9N2) virus From 16 to 22 May 2025, eight new cases of human infection with avian influenza A(H9N2) virus were reported to WHO in the Western Pacific Region. The eight new cases of human infection with avian influenza A(H9N2) virus were reported from China. Four cases were from Hunan, two cases were from Guizhou, one case was from Yunnan, and one case was from Chongqing, China, with onset in April 2025. There is no epidemiological link between them. Since December 2015, a total of 130 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 127 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. Human infection with avian influenza A(H10N3) virus From 16 to 22 May 2025, one new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The new case was reported from Shaanxi Province, China with an onset date of 13 April 2025. To date, five cases of human infection with avian influenza A(H10N3) have been reported globally. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 16 to 22 May 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus From 16 to 22 May 2025, no new outbreak of highly pathogenic avian influenza in animal were reported from Philippines to the World Organization for Animal Health (WOAH): For more information on animal infection with avian influenza viruses with potential public health impact, visit: • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) Avian Influenza Weekly Update Number 998| 4 • FAO Global Animal Disease Information System (EMPRES-i) Other updates • Influenza at the human-animal interface, Summary and risk assessment, from 20 March to 22 April 2025 22 April 2025 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animal and people 17 April 2025 • Genetic and antigenic characteristics of zoonotic influenza A viruses and development of candidate vaccine viruses for pandemic preparedness February 2025 • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2025 19 March 2025 • Recommended composition of influenza virus vaccines for use in the 2025-2026 northern hemisphere influenza season 28 February 2025 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020
Avian Influenza Weekly Update Number 999 | 1 Avian Influenza Weekly Update Number 999 30 May 2025 Human infection with avian influenza A(H5) viruses Human infection with avian influenza A(H5N1) virus From 23 to 29 May 2025, no new case of human infection with avian influenza A(H5N1) virus was reported to WHO in the Western Pacific Region. The last case was reported from Guangxi Autonomous Region, China with an onset date of 17 March 2025. From 1 January 2003 to 22 April 2025, a total of 465 cases of human infection with avian influenza A(H5N1) virus have been reported from six countries within the Western Pacific Region (Table 1). Of these cases, 313 were fatal, resulting in a case fatality rate (CFR) of 67.3%. Table 1: Cumulative number of laboratory-confirmed human cases (C) and deaths (D) of influenza A(H5N1) virus infection reported to WHO, by date of onset (1 January 2003 to 22 April 2025), Western Pacific Region. Country 2003-2009 2010-2014 2015-2019 2020-2024 2025 Total C D C D C D C D C D C D Australia 0 0 0 0 0 0 1 0 0 0 1 0 Cambodia 9 7 47 30 0 0 16 6 3 3 75 46 China 38 25 9 5 6 1 3 1 0 0 56 32 Indonesia 162 134 35 31 3 3 0 0 0 0 200 168 Lao PDR 2 2 0 0 0 0 1 0 0 0 3 2 Viet Nam 112 57 15 7 0 0 2 1 1 0 130 65 Total 323 225 106 73 9 4 23 8 4 3 465 313 Source: Confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2025 Globally, from 1 January 2003 to 22 April 2025, 973 cases of human infection with avian influenza A(H5N1) virus were reported from 25 countries. Of these 973 cases, 470 were fatal (CFR of 48.3%). Human infection with avian influenza A(H5N6) virus From 23 to 29 May 2025, no new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. Since 2014, a total of 93 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 57 deaths (CFR 61%) have been reported to WHO in the Western Pacific Region. The last case was reported from Anhui Province, China, with an onset date of 17 June 2024. Human infection with avian influenza A(H5) virus From 23 to 29 May 2025, no new case of human infection with avian influenza A(H5) virus was reported to WHO in the Western Pacific Region. The last case was reported from Tan An City, Long An Province, Viet Nam, with an onset date of 9 November 2024. Avian Influenza Weekly Update Number 999 | 2 Public health risk assessment for human infection with avian influenza A(H5) viruses Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. No sustained human-to-human transmission has been identified associated with the recent reported human infections with avian influenza A(H5). Available evidence suggests that influenza A(H5) viruses circulating have not acquired the ability to efficiently transmit between people, therefore sustained human-to-human transmission is thus currently considered unlikely at this time. The zoonotic threat remains elevated due to the spread of the viruses among birds. However, the overall pandemic risk associated with A(H5) is considered to not have significantly changed in comparison to previous years. WHO recommends that Member States remain vigilant and consider mitigation steps to reduce human exposure to potentially infected birds to reduce the risk of additional zoonotic infection. For information on risk assessments on Avian Influenza, see: Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animals and people, published on 17 April 2025. Human infection with avian influenza A(H3N8) virus From 23 to 29 May 2025, no new case of human infection with avian influenza A(H3N8) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 22 February 2023. To date, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death have been reported to WHO in the Western Pacific Region. Human infection with avian influenza A(H7N4) virus in China From 23 to 29 May 2025, no new case of human infection with avian influenza A(H7N4) virus was reported to WHO in the Western Pacific Region. To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reported from China on 14 February 2018. Human infection with avian influenza A(H7N9) virus in China From 23 to 29 May 2025, no new case of human infection with avian influenza A(H7N9) virus was reported to WHO in the Western Pacific Region. To date, a total of 1 568 laboratory-confirmed human infections with avian influenza A(H7N9) virus, including 616 fatal cases (CFR: 39%), have been reported to WHO since early 2013. The last case of human infection with avian influenza A(H7N9) reported to WHO in the Western Pacific Region was in 2019. Avian Influenza Weekly Update Number 999 | 3 Human infection with avian influenza A(H9N2) virus From 23 to 29 May 2025, no new case of human infection with avian influenza A(H9N2) virus were reported to WHO in the Western Pacific Region. Since December 2015, a total of 130 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 127 were reported from China, two were reported from Cambodia, and one was reported from Viet Nam. Human infection with avian influenza A(H10N3) virus From 23 to 29 May 2025, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The last case was reported from Shaanxi Province, China with an onset date of 13 April 2025. To date, five cases of human infection with avian influenza A(H10N3) have been reported globally. Most previously reported human infections with avian influenza viruses were due to exposure to infected poultry or contaminated environments. Since avian influenza viruses, including avian influenza A(H10N3) viruses, continue to be detected in poultry populations, further sporadic human cases could be detected in the future. Currently, available epidemiologic information suggests that the avian influenza A(H10N3) virus has not acquired the ability for sustained human-to-human transmission, thus the likelihood of spread among humans is low. Human infection with avian influenza A(H10N5) virus From 23 to 29 May 2025, no new case of human infection with avian influenza A(H10N5) was reported to WHO in the Western Pacific Region. To date, one case of avian influenza A(H10N5) virus has been reported from Zhejiang Province, China, with an onset date of 30 November 2023. Avian influenza A(H10) subtype viruses are known to be distributed in domestic and wild bird species worldwide. They are classified as low pathogenic and occasionally infect mammals (e.g., pigs). Human infection with avian influenza A(H10N5) is unusual; however, given the sporadic nature of human infection with H10Nx, this is not an unexpected event. There is no evidence of sustained human-to-human transmission of influenza A(H10Nx). Human infections of avian influenza need to be monitored and assessed for any indications of changes in transmissibility and virulence. Animal infection with avian influenza virus From 23 to 29 May 2025, no new outbreak of highly pathogenic avian influenza in animal were reported from Philippines to the World Organization for Animal Health (WOAH): For more information on animal infection with avian influenza viruses with potential public health impact, visit: • WOAH web page: Weekly disease information and Latest report on Avian Influenza • Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) • FAO Global Animal Disease Information System (EMPRES-i) Avian Influenza Weekly Update Number 999 | 4 Other updates • Influenza at the human-animal interface, Summary and risk assessment, from 20 March to 22 April 2025 22 April 2025 • Updated joint FAO/WHO/WOAH public health assessment of recent influenza A(H5) virus events in animal and people 17 April 2025 • Genetic and antigenic characteristics of zoonotic influenza A viruses and development of candidate vaccine viruses for pandemic preparedness February 2025 • Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2025 19 March 2025 • Recommended composition of influenza virus vaccines for use in the 2025-2026 northern hemisphere influenza season 28 February 2025 • Recommended composition of influenza virus vaccines for use in the 2025 southern hemisphere influenza season 27 September 2024 • WHO position paper: Vaccines against influenza 1 June 2022 • Assessment of risk associated with recent influenza A(H5N1) clade 2.3.4.4b viruses 21 December 2022 • WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic Interim guidance 20 September 2020