Surveillance, case investigation and contact tracing for monkeypox: interim guidance, 25 August 2022

- 1 - Surveillance, case investigation and contact tracing for monkeypox Interim guidance 25 August 2022 Key points • A multi-country outbreak of monkeypox is ongoing in all six WHO regions and the number of reported cases has been increasing since May 2022. The overall goal of surveillance, case investigation and contact tracing in this context is to stop human-to-human transmission and to control the outbreak. • The key objectives of surveillance and case investigation for monkeypox in the current context are to rapidly identify cases and clusters in order to provide optimal clinical care; to isolate cases to prevent further transmission; to identify, manage and follow up contacts to recognize early signs of infection; to identify risk groups for infection and for severe disease; to protect frontline health workers; and to tailor effective control and prevention measures. • As the number of cases increases with the expansion of surveillance activities, immediate actions should focus on: informing those who may be most at risk for monkeypox virus (MPXV) infection with accurate information; offering pre- and post-exposure vaccination to at risk population groups; stopping further spread; and protecting vulnerable individuals and frontline workers. • Clinicians should report suspected cases immediately to local and national public health authorities. • Probable and confirmed cases of monkeypox should be reported as early as possible, including a minimum dataset of epidemiologically relevant information, to WHO through IHR national focal points (NFPs) under Article 6 of the International Health Regulations (IHR 2005). • If monkeypox is suspected, case investigation should consist of clinical examination of the patient while using appropriate personal protective equipment (PPE), questioning the patient about possible sources of infection, and safe collection and dispatch of specimens for monkeypox virus laboratory examination. • As soon as a suspected case is identified, contact identification and contact tracing should be initiated. • Contacts of probable and confirmed cases should be monitored, or should self-monitor, daily for any sign or symptom for a period of 21 days from last contact with a case or their contaminated materials during the infectious period. • Quarantine or exclusion from work are not necessary during the contact tracing period as long as no symptoms develop. During the 21 days of monitoring, WHO encourages contacts without any symptoms to rigorously practice hand hygiene and respiratory etiquette, avoid contact with immunocompromised people, children or pregnant women, and avoid any form of sexual contact. Non-essential travel is discouraged. Changes from earlier version This is an updated version of the previous interim guidance on Surveillance, case investigation and contact-tracing published on 24 June 2022. On 23 July, the Director General of WHO declared the multi-country outbreak of monkeypox to be a Public Health Emergency of International concern (PHEIC). This interim guidance has been updated with the latest information on symptomatology and epidemiological parameters, and to align with the Temporary Recommendations issued by the Director General.1 The updated suspected case definition includes known contacts with prodromal signs or symptoms, and both suspected and probable case definitions have been updated to capture additional clinical characteristics such as mucosal lesions. New variables have been added to the minimal dataset of probable and confirmed cases to be shared with WHO. This version of the document contains the first definition of monkeypox-related death for surveillance purposes. It will be updated as further information becomes available. Surveillance, case investigation and contact tracing for monkeypox: interim guidance -2- Introduction This guidance serves to provide interim recommendations for surveillance, case investigation and contact tracing for human monkeypox in the context of the current global multi-country outbreak.2 Since May 2022, the number of monkeypox cases reported globally has been steadily increasing and many countries have reported their first monkeypox case ever.3 This is the first time that sustained community transmission is occurring in areas outside West or Central Africa. The incubation period of monkeypox has historically ranged from 5 to 21 days.2 Typically, the prodromal phase of clinical illness lasts 1-5 days during which time patients may experience fever, headache, back pain, muscle aches, and lymphadenopathy. This is followed by a second phase which typically occurs after the fever subsides, with the appearance of skin and/or mucosal rash, which might include a single or multiple lesions. Typically, the lesions progress through macules, papules, vesicles, and pustules, before crusting over and desquamating over a period of 2 to 4 weeks. In the context of this outbreak, patients are presenting more mucosal lesions than previously described, and often these are localized in the genital or perineal/perianal area as well as in the mouth and on the eyes.4 Lesions might appear at different stages of progression and it has been observed that the rash can develop prior to typical prodromal or constitutional symptoms (such as fever, fatigue). Ano-rectal pain and bleeding (e.g. due to proctitis) has also been reported more often in this outbreak. Lymphadenopathy remains a common feature, usually appearing early in the course of illness. Human-to-human transmission of monkeypox can occur through direct contact with infectious lesions of the skin or mucous membranes or body fluids from those lesions, this includes face-to-face, skin-to-skin, mouth-to-mouth or mouth-to-skin contact and respiratory droplets (and possibly short-range aerosols requiring prolonged close contact). The virus then enters the body through broken skin, mucosal surfaces (e. g. oral, pharyngeal, ocular, genital or anal), or via the respiratory tract. The infectious period can vary, but generally patients are considered infectious from the time of symptom onset until skin lesions have crusted, the scabs have fallen off and a fresh layer of skin has formed underneath. Transmission can also occur from the environment to humans from contaminated clothing or linens that have infectious skin particles (also described as fomite transmission). If shaken, these particles can disperse into the air and be inhaled, land on broken skin or mucosal membranes and lead to transmission and infection; one documented health worker infection has been published suggesting monkeypox was acquired through contact with contaminated bedding.5 Other two cases in health workers, in France6 and in Portugal (reported to WHO), have been infected through an accidental contaminated needle stick injury. For respiratory transmission, close proximity and extended exposure appear to be necessary. While virus has been found in the semen of affected patients,4,7–9 the role of sexual transmission through seminal fluids is not yet well understood. During pregnancy, virus can cross the placenta causing intrauterine exposure of the foetus and congenital infection of the infant.10 The sudden appearance of monkeypox in countries where this disease has never been reported or where in recent years there have only been cases linked to travel to/from West Africa — is unexpected. Transmission, initially amplified by travel and gatherings in several countries, has been sustained among men who have sex with men, and this group currently represents those at highest risk of getting infected.3 Most reported cases have not had severe disease,3,4,8,11,12 although many have developed complications and/or required hospitalization for management of severe pain.4,11 Surveillance, case investigation and contact tracing for monkeypox: interim guidance -3- Several monkeypox-related deaths have now been reported in countries outside West and Central Africa.3 Some, but not all, patients had underlying risk factors (e.g. being immunocompromised or immunosuppressed ). Several, but not all, patients died from encephalitis. The overall goal of surveillance, case investigation and contact tracing in this context is to break chains of human-to- human transmission and stop the outbreak. Transmission from and to animals Monkeypox is a zoonotic infection which can be transmitted from animals to humans, from humans to humans, and potentially from humans to animals. Current evidence suggests that the 2022 outbreak does not involve multiple zoonotic spillover events, and transmission is sustained through human-to-human spread. Surveillance of monkeypox in animal populations is beyond the scope of this document. Countries are encouraged to report cases of monkeypox in animals to the World Organization for Animal Health (WOAH) with all relevant animal health information as described in Article 1.1.5 of the Terrestrial Animal Health Code, by email to information.dept@woah.org. Surveillance Case Definitions The case definitions for use in this outbreak may be reviewed as more evidence becomes available. For further guidance on testing please refer to Laboratory testing for the monkeypox virus: Interim guidance.13 Suspected case: i) A person who is a contact of a probable or confirmed monkeypox case in the 21 days before the onset of signs or symptoms, and who presents with any of the following: acute onset of fever (>38.5°C), headache, myalgia (muscle pain/body aches), back pain, profound weakness or fatigue. OR ii) A person presenting since 01 January 2022 with an unexplained acute skin rash, mucosal lesions or lymphadenopathy (swollen lymph nodes). The skin rash may include single or multiple lesions in the ano-genital region or elsewhere on the body. Mucosal lesions may include single or multiple oral, conjunctival, urethral, penile, vaginal, or ano-rectal lesions. Ano-rectal lesions can also manifest as ano-rectal inflammation (proctitis), pain and/or bleeding. AND for which the following common causes of acute rash or skin lesions do not fully explain the clinical picture: varicella zoster, herpes zoster, measles, herpes simplex, bacterial skin infections, disseminated gonococcus infection, primary or secondary syphilis, chancroid, lymphogranuloma venereum, granuloma inguinale, molluscum contagiosum, allergic reaction (e.g., to plants); and any other locally relevant common causes of papular or vesicular rash. N.B. It is not necessary to obtain negative laboratory results for listed common causes of rash illness in order to classify a case as suspected. Further, if suspicion of monkeypox infection is high due to either history and/or clinical presentation or possible exposure to a case, the identification of an alternate pathogen which causes rash illness should not preclude testing for MPXV, as co-infections have been identified. Surveillance, case investigation and contact tracing for monkeypox: interim guidance -4- Probable case: A person presenting with an unexplained acute skin rash, mucosal lesions or lymphadenopathy (swollen lymph nodes). The skin rash may include single or multiple lesions in the ano-genital region or elsewhere on the body. Mucosal lesions may include single or multiple oral, conjunctival, urethral, penile, vaginal, or ano-rectal lesions. Ano- rectal lesions can also manifest as ano-rectal inflammation (proctitis), pain and/or bleeding. AND One or more of the following: • has an epidemiological linka to a probable or confirmed case of monkeypox in the 21 days before symptom onset • Identifies as gay, bisexual or other man who has sex with men • has had multiple and/or casual sexual partners in the 21 days before symptom onset • has detectable levels of anti-orthopoxvirus (OPXV) IgM antibodyb (during the period of 4 to 56 days after rash onset); or a four-fold rise in IgG antibody titer based on acute (up to day 5-7) and convalescent (day 21 onwards) samples; in the absence of a recent smallpox/monkeypox vaccination or other known exposure to OPXV • has a positive test result for orthopoxviral infection (e.g. OPXV-specific PCR without MPXV-specific PCR or sequencing)c Confirmed case: A person with laboratory confirmed monkeypox virus infection by detection of unique sequences of viral DNA by real-time polymerase chain reaction (PCR)c and/or sequencing. Discarded case: A suspected or probable case for which laboratory testing of lesion fluid, skin specimens or crusts by PCR and/or sequencing is negative for MPXVc. Conversely, a retrospectively detected probable case for which lesion testing can no longer be adequately performed (i.e., after the crusts fall off) and no other specimen is found PCR-positive, would remain classified as a probable case. A suspected or probable case should not be discarded based on a negative result from an oropharyngeal, anal or rectal swab. These case definitions were developed with a view to balance the importance of detecting cases and interrupting chains of transmission, while avoiding an overly sensitive definition that would overburden public health, diagnostic and treatment resources. Public health authorities may adapt these case definitions to suit local circumstances. All efforts should be made to avoid unnecessary stigmatization of individuals and communities potentially affected by monkeypox. These definitions are for surveillance purposes and should not be used to guide clinical management. WHO interim guidance for Clinical Management and Infection Prevention and Control for monkeypox has been published separately.5 a The person has been exposed to a probable or confirmed monkeypox case. Please see below definition of a contact. b Serology can be used for retrospective case classification for a probable case in specific circumstances such as when diagnostic testing through PCR of skin lesion specimens has not been possible, or in the context of research with standardized data collection. The primary diagnostic test for monkeypox diagnosis is PCR of skin lesion material or other specimen such as an oral or nasopharygeal swab as appropriate. Serology should not be used as a first line diagnostic test. c PCR on a blood specimen may be unreliable and should also not be used alone as a first line diagnostic test. If blood PCR is negative and was the only test done, this is not sufficient to discard a case that otherwise meets the definition of a suspected for probable case. This applies regardless of whether the blood PCR was for OPXV or MPXV specific. Surveillance, case investigation and contact tracing for monkeypox: interim guidance -5- Surveillance The key objectives of surveillance and case investigation for monkeypox in the current context are to rapidly identify cases and clusters of infections as well as the sources of infection as soon as possible in order to: provide optimal clinical care; isolate cases to prevent further transmission; identify, manage and follow-up contacts to recognize early signs of infection; identify risk groups for infection and for severe disease; protect frontline health workers; and tailor effective control and prevention measures. One case of monkeypox is considered an outbreak. Because of the public health risks associated with a single case of monkeypox, clinicians should report suspected cases immediately to national or local public health authorities regardless of whether they are also exploring other potential diagnoses, according to the case definitions above or nationally tailored case definitions. Probable and confirmed cases of monkeypox should be reported as early as possible, including a minimum dataset of epidemiologically relevant information, to WHO through national IHR focal points (NFPs) under Article 6 of the International Health Regulations (IHR 2005). Countries and clinicians should be on alert for signals related to patients presenting with monkeypox. It is important to note that patients may present to various community and other health facility settings including but not limited to primary care, fever clinics, sexual health services, infectious disease units, obstetrics and gynaecology, emergency departments, and dermatology clinics. Guidance for clinical management, infection prevention and control, and the safe collection of samples for confirmatory testing should therefore be disseminated widely.5,13 In countries detecting cases of monkeypox, epidemiological and transmission patterns should be investigated wherever possible in order to inform ongoing response activities to control the outbreak. Indicators for monitoring the quality of monkeypox surveillance include: 1. Proportion of cases with complete demographic information 2. Proportion of suspected cases with laboratory testing performed. 3. Proportion of cases with complete clinical and risk factor information. Indications for monkeypox testing Any individual meeting the definition for a suspected case should be offered monkeypox testing, where resources allow. In the absence of skin or mucosal lesions, PCR can be done on an oropharyngeal, anal or rectal swab. However, the interpretation of results from oropharyngeal, anal and rectal swabs requires caution; while a positive result is indicative of monkeypox infection, a negative result is not enough to exclude the infection. Due to the range of conditions that cause skin and mucosal rashes, it can be challenging to differentiate monkeypox solely based on the skin and mucosal clinical presentation, particularly for cases with an atypical presentation. The decision to test should be based on both clinical and epidemiological factors, linked to an assessment of the likelihood of infection. When suspicion of monkeypox infection is high due to history and/or clinical presentation, the identification of an alternate pathogen which causes rash illness should not preclude testing for MPXV, as coinfections have been identified. Given the epidemiological criteria observed in the outbreak, criteria such as being a man who has sex with men, reporting a high number of sexual partners in the prior three weeks, and having attended a gathering where a confirmed case was reported can be suggestive of the need to test for MPXV. For study purposes, countries can retrospectively expand their testing to residuals of specimens collected before May 2022 from patients presenting for sexually transmitted infection (STI) screening and/or with symptoms suggestive of monkeypox. Surveillance, case investigation and contact tracing for monkeypox: interim guidance -6- Reporting WHO has published and updated the monkeypox Case Reporting Form (CRF)14 which constitutes the minimum data countries are requested to report to the respective WHO Regional Office, and includes the following information: • Record ID • Reporting Country • Reporting location (subnational ADM1 level) • Date of notification • Case classification • Age, sex, gender, sexual orientation • Health worker • Sex worker • Medical history (pregnancy, immunosuppression, HIV status, HIV PrEP use) • Smallpox and monkeypox vaccination status and vaccination date • Clinical signs or symptoms • Date of onset of first symptoms • Presence of rash • Date of rash onset • Name of concurrent sexually transmitted infections • Number of sex partners in the last three months • Monkeypox treatment • Hospital admission • Intensive care unit (ICU) admission • Complications • Recent travel history (in the 21 days before onset of illness) • Recent exposure to a probable or confirmed case (in the 21 days before onset of illness) • Nature of contact with probable or confirmed case (where relevant) • Contact with animals (in the 21 days before onset of illness) • Mode of transmission • Type of specimen collected for diagnosis • Method of confirmation (where done) • Genomic characterization and clade (if available) • Accession number of the genomic sequence uploaded to public database • Outcome status at time of reporting Case investigation During human monkeypox outbreaks, close physical contact, including sexual intercourse, with infected persons is the most significant risk factor for monkeypox virus infection. If monkeypox is suspected, the investigation should consist of: (i) clinical examination of the patient using appropriate infection prevention and control (IPC) measures as reported in the specific guidance.5 (ii) questioning the patient about possible sources of infection and the presence of similar illnesses in the patient’s community and contacts, both prior to becoming a case (backward contact tracing) to identify the source, and from the beginning of the infectious period through isolation (forward contact tracing) to reduce onward transmission. Current evidence suggest that a case is infectious from the symptom onset to the moment all vesicle scabs fall off.15,16 (iii) safe collection and dispatch of specimens for monkeypox laboratory examination.13 Surveillance, case investigation and contact tracing for monkeypox: interim guidance -7- In addition to the minimum dataset (CRF), WHO has published and updated the monkeypox Case investigation form (CIF) designed as a tool for Member States and researchers to conduct in-depth epidemiological investigation of suspected, probable and confirmed cases of monkeypox, as well as their contacts, either prospectively or retrospectively. The CIF is designed to address the key unknowns about MPXV transmission in this outbreak, such as infectious period, most efficient route of transmission, clinical presentation and main risk factors for infection and severe disease. The full form is meant for in-country use and the data are not required to be reported to WHO.14 Exposure investigation should cover the period of 21 days prior to symptom onset. Any patient with suspected monkeypox should be isolated during the presumed and known infectious periods, that is during the prodromal and rash stages of the illness, respectively. Laboratory confirmation of suspected cases is important but should not delay implementation of public health actions. Retrospective cases found by active search may no longer have the clinical symptoms of monkeypox (they have recovered from acute illness) but may exhibit scarring and other sequelae. It is important to collect epidemiological information from retrospective cases in addition to active ones. Retrospective cases cannot be laboratory confirmed; however, serum from retrospective cases can be collected and tested for anti-orthopoxvirus IgM and/or IgG antibodies to aid in their probable case classification. Samples taken from persons with suspected monkeypox should be safely handled by trained staff working in suitably equipped laboratories. National and international regulations on transport of infectious substances should be strictly followed during sample packing and transportation. Careful planning is required to consider national laboratory testing capacity. Clinical laboratories should be informed in advance of samples to be submitted from persons with suspected or confirmed monkeypox, so that they can minimise risk to laboratory workers and, where appropriate, safely perform laboratory tests that are essential for clinical care. For more details, please refer to the Laboratory testing for monkeypox virus interim guidance.13 Contact tracing Contact tracing is a key public health measure to control the spread of infectious disease pathogens such as monkeypox virus. It allows for the interruption of chains of transmission and can also help people at a higher risk of developing severe disease to more quickly identify their exposure, so they can monitor their health status and seek medical care quickly if they become symptomatic. Cases should be promptly interviewed as soon as possible to elicit the names and contact information of all potential contacts and identify places visited where contact with other people may have occurred. Contacts of cases should be notified within 24 hours of identification and advised to monitor their health status and seek medical care if they develop symptoms. In the current context, as soon as a suspected case is identified, contact identification and contact tracing should be initiated, while further investigation of the source case is ongoing to determine if the case can be classified as probable or confirmed; in the event that the case is discarded, contact tracing may be stopped. Definition of a contact A contact is defined as a person who has been exposed to an infected person during the infection period i.e the period beginning with the onset of the index case’s first symptoms and ending when all scabs have fallen off, and who has one or more of the following exposures with a probable or confirmed case of monkeypox: • direct skin-to-skin and skin-to-mucosal physical contact (such as touching, hugging, kissing, intimate or sexual contact) • contact with contaminated materials such as clothing or bedding, including material dislodged from bedding or surfaces during handling of laundry or cleaning of contaminated rooms Surveillance, case investigation and contact tracing for monkeypox: interim guidance -8- • prolonged face-to-face respiratory exposure in close proximity • respiratory exposure (i.e., possible inhalation of) or eye mucosal exposure to lesion material (e.g., scabs/crusts) from an infected person • The above also apply for health workers potentially exposed in the absence of proper use of appropriate personal protective equipment (PPE)5 Contact identification Cases can be prompted to identify contacts across a number of contexts, including household, workplace, school/nursery, sexual contacts, healthcare (including laboratory exposure), houses of worship, transportation, sports, bars/restaurants, social gatherings, festivals, and any other recalled interactions. Attendance lists, passenger manifests, etc. can be further used to identify contacts. Experience of the last months shows that some cases may be reluctant or unable to provide contact information for all contacts, especially of sexual contacts. To overcome this challenge, public health authorities should encourage cases to directly notify their contacts and provide them advice on how best to do this. Research in sexually transmitted diseases has shown that activities such as partner notification, i.e. voluntarily notifying a partner that they have been exposed to an infection, can yield good contact tracing results.17 In the context of monkeypox, cases should be offered adequate counselling on how to notify their contact, the recommendations for the contact’s movement and activities, and referral information about health providers who can support the contact with information, or in case of symptoms, with health services. If possible, all information should also be provided in written form (e.g., leaflets, cards, links to webpages, and QR codes) to avoid misinterpretation. Organizers of events or managers of venues or community settings from which monkeypox cases have been identified may also be involved in contact notification. Such venues may include saunas, bathhouses, or personal service settings such as tattoo parlours, where physical contact, including sex, among participants occurs. If a confirmed monkeypox case reports having attended an event or a venue where close physical contact took place during the infectious period, but is unable to identify all possible contacts, public health authorities can liaise with the event organizers to send a general notification to all participants about the potential risk of exposure. Also, in this case all relevant information about monkeypox, including referral to healthcare, needs to be provided together with the notification. Once contacts have been identified, they should be informed of their exposure, their risk of developing infection, the symptoms of monkeypox, and when symptoms may appear. Contact monitoring Contacts should be monitored, or should self-monitor, daily for the onset of signs or symptoms for a period of 21 days from the last contact with the probable or confirmed case or their contaminated materials during the infectious period. Signs and symptoms of concern include headache, fever, chills, sore throat, malaise, fatigue, rash, and lymphadenopathy. Contacts should monitor their temperature twice daily. During the 21 days monitoring period contacts should regularly practice hand hygiene and respiratory etiquette. As a precautionary measure, asymptomatic contacts should not donate blood, cells, tissue, organs, breast milk, or semen while they are under symptom surveillance. Contacts should also try to avoid physical contact with children, pregnant women, immunocompromised individuals and animals, including pets. Asymptomatic contacts that adequately and regularly monitor their status can continue routine daily activities such as going to work and attending school (i.e., no quarantine is necessary). Local health authorities may choose to advise for pre-school children who have been exposed to a case of monkeypox to not attend day care, nursery or Surveillance, case investigation and contact tracing for monkeypox: interim guidance -9- other group settings during the contact follow-up period. Options for monitoring by public health authorities are dependent on available resources. Contacts can be monitored passively, actively, or directly. In passive monitoring, identified contacts are provided with information on the signs and symptoms to monitor, permitted activities, and how to contact the public health department if signs or symptoms develop. Active monitoring is when public health officials are responsible for checking at least once a day to see if a person under monitoring has self-reported signs/symptoms. Direct monitoring is a variation of active monitoring that involves at least daily either physically visiting, visually examining via video for signs of illness, or connecting by telephone to enquire about onset of any symptoms. A contact who develops prodromal symptoms or lymphadenopathy, without rash should be isolated and closely examined for signs of rash. In absence of skin or mucosal lesions, PCR can be done on an oropharyngeal, anal or rectal swab. However, the interpretation of results from oropharyngeal, anal or rectal swabs requires caution; while a positive result is indicative of monkeypox infection, a negative result is not enough to exclude infection. A contact with a positive oropharyngeal, anal or rectal swab is to be considered a confirmed case, while if it is negative the contact needs to continue monitor the signs of rash for the next five days. If no rash develops, the contact can return to temperature monitoring for the remainder of the 21 days. If the contact develops skin or mucosal lesions, they need to be isolated and evaluated as a probable case, and a specimen from the lesions should be collected for laboratory analysis to test for monkeypox. Any individual with signs and symptoms compatible with monkeypox virus infection; or being considered a suspected, probable, or confirmed case of monkeypox by jurisdictional health authorities; or who has been identified as a contact of a monkeypox case and, therefore, is subject to health monitoring, should avoid undertaking any travel, including international, until they are determined as no longer constituting a public health risk. Exemptions include any individual who need to undertake travel to seek urgent medical care or flee from life-threatening situations, such as conflict or natural disasters; and contacts for whom pre-departure arrangements to ensure the continuity of health monitoring are agreed upon by sub-national health authorities concerned, or, in the case of international travel, by national health authorities. Cross-border workers, who are identified as contacts of a monkeypox case, and, hence, under health monitoring, can continue their routine daily activities provided that health monitoring is duly coordinated by the jurisdictional health authorities from both/all sides of the border. 1 Monitoring exposed health workers Any health worker who has cared for a person with probable or confirmed monkeypox should be alert to the development of symptoms that could suggest monkeypox virus infection, especially within the 21-day period after the last date of care. WHO recommends that health workers with an occupational exposure to MPXV should notify infection control, occupational health, and public health authorities to receive an assessment and management plan of the potential infection.5 Health workers who have occupational exposures (i.e., needlestick injuries or contact with case while not wearing appropriate PPE) to patients with monkeypox or possibly contaminated materials should follow national infection control guidance, do not need to be excluded from work duty if asymptomatic, but should actively monitor for symptoms, which includes measurement of temperature at least twice daily for 21 days following the exposure; and should be instructed not to work with vulnerable patients during this period. Prior to reporting for work each day, the health worker should be interviewed regarding evidence of any relevant signs or symptoms as above. Where vaccines are available, post-exposure vaccination (ideally within four days of exposure) is recommended for health workers, including laboratory personnel, who came in contact with a case or potentially infectious material Surveillance, case investigation and contact tracing for monkeypox: interim guidance -10- without use of appropriate PPE. For more details on vaccines and immunization for monkeypox, please consult the specific guidance.18 Travel-related contact tracing Public health officials should work with transportation authorities, travel operators and public health counterparts to assess potential risk of exposure and to identify contacts (passengers and others) who may have had exposure to a case while travelling. If a probable or confirmed case is reported in a long-distance travel conveyance (e.g., lasting more than 6 hours), travellers seated in the same row, two rows in front and two rows behind the sick traveller as well as the cabin crew who served the case, can be considered contacts of the case. Any passenger or crew team member who did not report physical contact with a symptomatic case and was wearing PPE such as face mask for COVID-19 should not be considered a monkeypox contact. More specific evaluations for each scenario need to be assessed on a case-by-case basis by national and local health authorities. Monitoring and evaluation of contact tracing quality Indicators for monitoring the quality of monkeypox contact tracing include: 1. Proportion of probable and confirmed cases with identified contacts 2. Number of contacts reported per probable and confirmed case 3. Proportion of identified contacts with complete follow-up information 4. Proportion of cases coming from a contact tracing list 5. Proportion of high and medium risk contact who received post-exposure prophylaxis. Definition of monkeypox death for surveillance purposes A monkeypox death for surveillance purposes is defined as a death resulting from a clinically compatible illness in a probable or confirmed monkeypox case, unless there is a clear alternative cause of death that cannot be related to monkeypox infection (e.g. trauma). The diagnosis for monkeypox can also be confirmed after the death has occurred if there is sufficient lesion material to perform a PCR testing. There should be no period of complete recovery between the illness and death. Data collection and sharing In order to facilitate data collection of cases following the requested minimum dataset, WHO has prepared a macro- enabled Microsoft Excel form that countries have received through IHR communication channels; however, any reporting format agreed with the respective Regional Office may be used. WHO has also implemented the in-depth case investigation form in the Go.Data platform19 to facilitate local capture, analysis, and/or sharing of the relevant data. Analysis of transmission chains and network visualization have been used in past outbreaks to identify clusters, understand patterns of exposure, and quantify viral transmission across different settings. In the context of the current monkeypox outbreak, understanding these patterns of transmission will be critical not only to finding which control measures are effective, but will allow for the characterization of the extent of respiratory transmission and determining if multiple introductions (human or zoonotic) have occurred. To date, limited tools are available for countries to be able to graph these chains of transmission and identify clusters or contexts of transmission in real-time. Through its "visualization" feature, Go.Data will allow Member States, partners and institutions to enhance outbreak response activities, particularly by visualizing, in real-time, chains of transmission which will facilitate the monitoring of disease progression as well as identifying potential new cases that are missed through undetected circulation of the virus. The Go.Data monkeypox outbreak template and associated metadata description can be obtained upon request by emailing godata@who.int, and technical support for implementation is available from WHO. Surveillance, case investigation and contact tracing for monkeypox: interim guidance -11- Data collected in a harmonized way through the WHO case investigation form could also be collated across multiple countries in a collaborative effort, increasing the sample size and allowing for more robust analyses. Methods The recommendations in this guidance are based on the inputs of expert contributors (see below); and a rapid literature search conducted by WHO, focusing on case definitions and epidemiology guidance previously developed for other monkeypox outbreaks. Plans for updating WHO continues to monitor the situation closely for any changes that may affect this interim guidance. Should any factors change, WHO will issue a further update. Otherwise, this interim guidance will expire three months after the date of publication. Contributors This guidance was developed through the contributions of an expert group from the WHO secretariat in headquarters and regional offices, in consultation with the Strategic and Technical Advisory Group on Infectious Hazards (STAG-IH) and clinical and laboratory experts in Portugal, Spain, Sweden, the United Kingdom, and the United States of America. Additional contributions have been provided by colleagues from the United States Centers for Disease Control and Prevention (CDC) and the European Centre for Disease Prevention and Control (ECDC). Funding source Funded by WHO. References 1 World Health Organization (WHO). 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