WORLD HEALTH ORGANIZATION
ORGANISATION MONDIALE DE LA SANTE
REGIONAL OFFICE FOR THE WESTERN PACIFIC BUREAU REGIONAL DU PACIFIQUE OCCIDENTAL
REGIONAL COMMITTEE Forty-ninth session Manila 14–18 September 1998 Provisional agenda item 10
WPR/RC49/6 31 July 1998 ORIGINAL: ENGLISH
ANNUAL REPORT ON SEXUALLY TRANSMITTED DISEASES, HIV INFECTION AND AIDS At its forty-eighth session in September 1997, the Regional Committee for the Western Pacific adopted resolution WPR/RC48.R3. This resolution requested the Regional Director to continue to report annually to the Regional Committee on the situation of sexually transmitted diseases, HIV infections and AIDS. The Regional Committee also asked the Regional Director to report on antiretroviral treatments as well as on the methodologies used for estimations and projections. HIV epidemics are continuing in many countries of the Region. The high incidence and prevalence of sexually transmitted diseases (STDs) are key contributors to high or increasing HIV transmission levels in some countries. In a few countries of the Region, the number of HIV infections appears to be stabilizing or even declining. Many countries have begun to reinforce their STD and HIV prevention and control
activities. However, action over the next few years will be crucial in determining the scale of the epidemic. To prevent major epidemics in many of the countries of the Region, Member States are urged to intensify implementation of prevention and control activities and to continue to work with WHO on the surveillance, prevention and control of STDs and HIV. Antiretroviral treatment for HIV/AIDS infection has recently proved to be effective in reducing morbidity and mortality related to HIV infection and AIDS, and in reducing vertical HIV transmission. Antiretroviral agents have also been used for post-exposure prophylaxis against HIV. However, a number of important issues have to be considered before antiretroviral treatment is introduced widely in the Region. education. This document presents an overview of actions taken and progress made since the fortyeighth session of the Regional Committee, for the information and discussion of the Committee at its forty-ninth session. These include the cost-effectiveness of such treatment compared with the cost of HIV prevention activities such as STD management and preventive
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1. INTRODUCTION
This report focuses on the activities undertaken by the Regional Office in the second half of 1997 and the first half of 1998. It includes sections on the epidemiological situation in the Region and an update on activities carried out by WHO in the Region. Annex 1 contains a report on the methodology used by WHO for HIV, AIDS and STD estimations and projections, as requested by the Regional Committee at its forty-eighth session. The Regional Committee also asked for information on the use of antiretroviral agents to reduce HIV infection and AIDS morbidity and mortality. A report on antiretroviral agents is contained in Annex 2.
2. EPIDEMIOLOGICAL SITUATION
2.1
AIDS and HIV A cumulative total of 15 557 cases of AIDS had been reported in the Region by May 1998.
However, underreporting and underdiagnosis of AIDS are common. The Regional Office estimates that, by the end of 1997, a cumulative total of more than 40 000 cases of AIDS had occurred. Of these, 16 000 were new cases in 1997. The Regional Office projects that by 2000, there will be over 50 000 new AIDS cases per year. A cumulative total of 84 910 HIV infections had been reported in the Western Pacific Region by May 1998. Of these, 33.1% were attributed to sexual transmission (16.3% through heterosexual sexual contact and 16.8% through homosexual or bisexual sexual contact); 36.5% to injecting drug use; 1.9% to infected blood or blood products; and 0.6% to transmission from mother to child. In 27.6% of cases, the mode of transmission was not stated or was unknown. Over the years, an increasing trend of heterosexual transmission has been observed. The Regional Office has continued to work with Member States to update estimations of HIV prevalence and annual AIDS incidence (see Annexes 3 and 4), in order to provide a more realistic assessment of the epidemic. It is estimated that by 1997 more than 700 000 individuals in the Region
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were HIV-infected. By 2000, it is projected that the number of HIV-infected individuals in the Region will exceed 1.5 million. The total number of HIV infections being reported in the Region has increased each year. However, the Region continues to experience a moderate HIV epidemic in comparison with other parts of the world. From the available data, four patterns of HIV transmission are apparent: − established and increasing HIV epidemics predominantly among heterosexuals in Cambodia and Papua New Guinea, and among injecting drug users (IDUs) in China and Viet Nam; − low levels of HIV transmission in Japan, Pacific island countries, the Philippines, and the Republic of Korea; − declining HIV epidemics in Australia and New Zealand; and − a stabilized epidemic in Malaysia, most of which is among injecting drug users. The Regional Office has prepared short-term projections for HIV and AIDS for 13 countries and areas affected by AIDS (see Annex 4).
2.2
Sexually transmitted diseases WHO estimates that more than 35 million new cases of curable sexually transmitted diseases
(gonococcal, chlamydial, syphilitic and trichomonial infections) occur in the Region every year. Chlamydial infections have reached epidemic levels, with more than 30 million new cases occurring in the Region every year (see Annex 5). STD infection rates among the sexually active population generally vary from 2% to 5%, and from 20% to 40% among commercial sex workers. These data emphasize the need to target commercial sex workers and their clients as priority groups for STD prevention and treatment. Epidemiological surveillance has continued to discover increasing gonococcal antibiotic resistance all over the Region. This is resulting in the need to adapt treatment, often by using more costly drug regimens.
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3. ACTIVITIES IN THE REGION
During the past year, the Regional Office provided a wide range of technical support at regional and country levels. It continued to support the development of STD and HIV/AIDS
epidemiological surveillance and the development of STD programmes (including STD treatment, education and programme management). STD, HIV and AIDS epidemiological data have been collected and analysed on a regular basis. The monitoring of gonococcal sensitivity in the Region has been extended. Two issues of the WPRO STD/HIV/AIDS Surveillance Report, including a special issue for the 50th anniversary of WHO, have been produced and widely distributed. Two regional meetings on epidemiology surveillance were organized. A regional STD, HIV and AIDS surveillance report was prepared in collaboration with Member States for the 4th International Congress on AIDS in Asia and the Pacific held in Manila in October 1997. The Regional Office has developed a standard protocol for STD prevalence surveys. This protocol has now been adapted for selected sites in China, Malaysia, Samoa and Vanuatu. The integrated computerized database for STDs, HIV and AIDS at the Regional Office has been regularly updated, and its use is being promoted in the Region. Support has been provided to countries for the implementation of HIV surveillance (Cambodia, China, the Philippines), analysis of data and design of estimations and projections. Guidelines for HIV and AIDS surveillance are being revised, and STD surveillance guidelines are being developed. Training courses in STD programme management were held for 19 countries of the Pacific and for Malaysia. An intercountry STD programme management “training of trainers” course was held for participants from Cambodia, China, the Lao People’s Democratic Republic, Mongolia and Viet Nam. Country-specific courses for Papua New Guinea and the Philippines are also planned. Support materials have been developed and distributed, including Syndromic Case Management of Sexually Transmitted Diseases: A Guide for Decision-Makers, Health Care Workers, and Communicators. Funds were provided for the translation and local production of STD materials in Cambodia, China, and Viet Nam. Guidelines for the organization of specialized STD services, including those at the referral level, are under development. STD policy guidelines were developed and field tested in Kiribati.
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The delivery of STD education and health services to commercial sex workers has been promoted, and a regional meeting on this topic will be held in late 1998. An STD education and services project for sex workers was started in 1997 in the Philippines, and will be evaluated in late 1998. Study tours to the Philippines to examine government and nongovernmental STD services for sex workers are being implemented. Support is also being provided for the development of STD education materials for sex workers in China, the Philippines, and Viet Nam. Efforts are underway to support wider STD education, and to improve the access to care for people with STD infections. STD education workshops have been held in Cambodia, Malaysia and Viet Nam. Community and district-based interventions with sex work establishments, private doctors and pharmacists to encourage people to seek medical treatment for STD infections are underway in China and Viet Nam. The Regional Office is also supporting a project in China to promote “HIV and STDs as an entry point for health-promoting schools”. A briefing package on STDs for secondary and further education teachers has been developed, and is being distributed. In Cambodia, support has been provided to improve the treatment of STDs within maternal and child health (MCH) and family planning (FP) services and the military health services. Support has also covered developing AIDS care protocols and models to assist home-based care for people with AIDS; adapting “100% condom use” to the Cambodian situation; and improving STD and HIV/AIDS programme management. The Regional Office is working with the Government and nongovernmental organizations in the Philippines to improve and expand national STD health services. Activities include: holding workshops on innovative approaches to STD services; developing a model for local government STD activities; validating STD syndromic management algorithms; conducting projects to integrate STD management into FP services; and establishing local revolving drug funds to improve access to STD drugs. With regard to safe blood issues, technical reviews of national-level policies were undertaken in Malaysia and the Philippines. Close collaboration has been maintained with UNAIDS and other partners involved in STD and HIV/AIDS prevention and control activities at country and regional levels.
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WPR/RC49/6 page 7 ANNEX 1
METHODOLOGIES USED FOR HIV, AIDS AND STD ESTIMATIONS AND PROJECTIONS HIV and AIDS estimations and projections For the past two years, the Regional Office and the Joint United Nations Programme on HIV/AIDS (UNAIDS) have collaborated to produce regional estimations and short-term (three-year) projections for the prevalence of HIV infection in the Region. Estimations and projections were also produced for the yearly incidence of AIDS cases in the largest countries of the Region. The Regional Office has worked with national governments and institutions involved in surveillance to collect and analyse HIV and AIDS data at country level. One outcome has been significant improvements in the sources of information on HIV infections. In order to estimate the prevalence of HIV, the general approach used for country estimations was to apply specific infection rates from representative subgroups to similar, larger population groups. For example, the prevalence rate for sex workers taken from sentinel surveillance figures was applied to the estimated number of sex workers in the country as a whole. In a similar way, HIV prevalence rates for pregnant women attending antenatal clinics in urban areas were used to estimate urban prevalence rates. The prevalence rate of military recruits from towns and villages was used to estimate the prevalence rate of the population of rural areas. In making these estimations, necessary adjustments were made to reflect the sex differentials. All of these estimations were then combined to give a weighted estimated total of people infected with HIV for the country as a whole. In countries experiencing a large-scale HIV epidemic, it was necessary to estimate: past and present incidence of AIDS; AIDS deaths; and the number of people living with HIV. This was done by using Epimodel, a relatively simple computer program developed by WHO in 1987 and improved over the years. This program has proved to be reliable, but it depends on having enough data points to draw an accurate epidemiological curve. In the most recent estimations and projections, different progression rates from HIV to AIDS for adults and children were used in different countries. The same is true for the rate of vertical transmission, which is mainly influenced by the level of breast-feeding (in the absence of prophylactic antiretroviral treatment or elective caesarean section).
WPR/RC49/6 page 8 Annex 1 “Back projection models” were used to generate data for Australia and New Zealand, where the reporting of AIDS cases is good. These models use AIDS incidence data to estimate prior HIV incidence, using knowledge about the rate of progression from initial HIV infection to AIDS. These models are widely used for countries with good AIDS case reporting. In the Philippines, current data show a low level of HIV infection. Therefore, projections were made on the basis that HIV transmission will remain at the low level observed over the past years. For China, estimations and projections provided by the national authorities were used.
Limitations of HIV/AIDS estimations and projections Models can only be developed if enough data are available to construct a specific epidemiological curve. For countries where no reliable information is available, estimations and projections were not constructed. In these cases, the 1994 prevalence rate published by WHO in 19951 was applied to the current population. This gave conservative estimations of the epidemic. The increasing use of antiretroviral life-prolonging therapies will change future estimations. The relationships between new infections, HIV prevalence, AIDS and death has been relatively predictable for some years, but these relationships will change in ways that cannot yet be foreseen. The existing version of Epimodel does not allow for changes in progression rates over time. The use of antiretroviral treatments and improvements in care for opportunistic infections will have major effects on the life-spans of people with HIV in countries where these treatments are widely available. Given the changing availability of treatments, new and more flexible epidemiological projection models will be needed in the future. Similarly, rates of transmission from mother to child may alter radically if there is widespread access to HIV testing, counselling, safe alternatives to breast-feeding, and short-course zidovudine (AZT) treatment for pregnant women.
1
WER 1995;70:353–360.
WPR/RC49/6 page 9 Annex 1
STD estimations All estimations were based on reviews of available ad hoc STD prevalence surveys. These surveys were either documented in published scientific reports produced in the respective Member States or collected through a review of reports published in national and international scientific journals. Only documents published between 1990 and 1997 were reviewed. Findings from those surveys which were well designed and had good laboratory support were used. No estimation was produced when data were unavailable or were thought to be insufficient. Data were used to develop estimations for the most common and curable STDs, namely syphilis, gonorrhoea, chlamydia and trichomoniasis. Only data obtained from subgroups considered to represent the general population were used. These subgroups included pregnant women, blood donors and military recruits. When several different infection rates were available for a given STD, country-based epidemiologists were consulted to identify the “mean” figure to use for the estimation. Prevalence figures were calculated assuming that the STD infection rates could be extended to the adult population over 15 years old. Although it is true that repeated episodes of STDs might occur in the same individual within a one-year period, no adjustment of the estimation was made to reflect this. Since data used in this process were gathered using point prevalence surveys, the estimations can also be considered to be minimum yearly incidence values for gonoccocal, chlamydial and trichomonial infections.
Revision of estimations and projections The current estimations and projections have so far been good at predicting the general nature and trend of HIV epidemics in countries in the Region. These estimations and projections are continually being revised (both upwards and downwards), as countries improve their surveillance systems and collect more information. This includes information about infection levels in different populations, and about behaviour that may lead to, or protect against, infection.
WPR/RC49/6 page 10 Annex 1 These estimations and projections are useful as instruments for public health decisionmaking. They can guide national programmes and help potential partners to improve surveillance systems and programmes.
WPR/RC49/6 page 11 ANNEX 2
ANTIRETROVIRAL AGENTS IN THE TREATMENT OF HIV/AIDS
Use of antiretroviral agents for asymptomatic and symptomatic HIV infections Current treatments and their effectiveness Current antiretroviral agents for HIV/AIDS can be divided into two major classes of drugs: (1) reverse transcriptase inhibitors (RTIs), and (2) protease inhibitors (PIs). RTIs are further divided into nucleoside (NRTI) and non-nucleoside (NNRTI) subclasses. A third class, integrase inhibitors, is being developed. These agents target enzymes involved in viral functioning. They are listed in Table 1. Table 1. Common antiretroviral agents used for HIV/ AIDS treatment Transcriptase inhibitor (RTIs) Nucleoside (NRTI) Non-nucleoside (NNRTI) Protease inhibitor (PIs)
Didanosine (ddI) Lamivudine (3TC) Stavudine (d4T) Zalcibatine (ddC)
Zidovudine (AZT) Delvaridine Nevirapine Indanavir
Saquinavir Palinavir Nelfinavir
Combination therapies (often using three antiretroviral drugs) have been shown to reduce HIV viral concentration in the blood significantly, and to increase the response of the immune system. Use of antiretroviral agents has led to significant clinical improvements in patients and increased survival time (some recent surveys have shown a reduction of mortality by 60%), although long-term effects (i.e. more than two years) are not known. Combination therapy usually uses both RTIs and PIs. The most recent HIV treatment and advise
guidelines recommend using protease-based three-drug therapy for AIDS patients,
symptom-free HIV-infected individuals to delay treatment. Research on newer combinations is ongoing. For example, hydroxyurea (a drug previously used to treat leukaemia), combined with ddI and d4T, has also been shown to reduce the level of HIV in the blood.
WPR/RC49/6 page 12 Annex 2 Limitations of antiretroviral agents The HIV virus reproduces rapidly, and this results in many mutations. These mutations sometimes result in changes in the enzymes, so they are no longer inhibited by antiretroviral agents. The use of antiretroviral agents may lead to more of these mutations, resulting in drug-resistant HIV strains. It now appears that resistance to antiretroviral agents can develop rapidly when the antiretroviral agents are used on their own. Therefore the use of zidovudine (AZT) on its own is no longer recommended (except for the brief periods needed to reduce mother-to-child transmission of the virus, or as prophylaxis for a maximum of 4-6 weeks in prevention of post-exposure). Combination therapy costs about US$ 1000 per month per person, and requires close clinical and biological monitoring. Because of the numerous side effects and treatment constraints, it is often difficult for patients to adhere to antiretroviral treatment regimens. Treatment adherence is often less than 50%. More than 30 pills a day have to be taken at times that interfere with normal eating patterns and social and work obligations. Many patients find it impossible to comply with such a regimen for the rest of their lives. A key requirement is that the patient has accepted his or her diagnosis and is able to share his or her status with others in order to support these difficult regimens. It is not known how long the benefits of combination therapy will last. Resistance to drug treatments remains difficult to predict, manage, or detect. Guidance on many crucial questions concerning these therapies, such as when to begin, when to stop, when to change drug and which drug to use are being developed by various centres in the world, and no standard answers can be given as yet. Treatment eligibility criteria, including issues of adherence and affordability, need to be established. Once the patient is declared eligible for treatment, the decision to start treatment should be made by him or her. Use of antiretroviral agents after exposure to body fluids of HIV-infected individuals The efficacy and ethical considerations of post-exposure prophylaxis against HIV (PEP) have been widely discussed. PEP is available in a few countries for specific circumstances, e.g. needle injuries among health workers who may have been exposed to HIV. These issues are still being debated and WHO and UNAIDS have not yet developed guidelines on PEP. PEP often uses two
WPR/RC49/6 page 13 Annex 2 nucleoside drugs (and sometimes a protease inhibitor), taken within 24 to 48 hours of exposure (ideally one or two hours after exposure). It is usually administered for four to six weeks, if tolerated. However, three issues should be noted. First, the average risk of seroconvertion following percutaneous exposure is actually very low (0.3%). Second, data on the efficacy of antiretroviral agents in PEP and on the toxicity of antiretroviral agents in non-infected individuals is scarce. Third, the approach depends on rapid action, and on knowing the serostatus of both the recipient and the source patient. Use of antiretroviral agents in the reduction of mother-to-child HIV transmission (MTCT) Transmission of HIV from mother to child can occur during pregnancy; during delivery and through breast-feeding. In a concerted effort to stop mother-to-child transmission of HIV, in 1997 UNAIDS, WHO and UNICEF developed a policy statement on HIV and infant feeding (see Appendix) and in 1998 a comprehensive set of guidelines that support the use of alternatives to breast-feeding for infants born to women infected with HIV was produced. The guidelines are intended to help governments devise national policies to reduce the risk of HIV transmission through breast-feeding and to assist health care managers in providing services and support. The guidelines stress the importance of protecting, promoting and supporting breast-feeding as the best method of feeding for infants whose mothers are HIV-negative or who do not know their HIV status. However, they support alternatives to breast-feeding for mothers who test positive for HIV. It has been known since 1994 that the risk of mother-to-child transmission of HIV could be reduced by at least two-thirds (from 25% to 8%) by giving AZT to HIV-infected pregnant women. AZT is administered orally to women five times a day, starting on average at 26 weeks gestation and continuing throughout pregnancy. It is then given intravenously during labour, and orally four times a day to infants (who are not breast-fed) for six weeks after they are born. In countries where this regimen has been implemented, significant declines in perinatal HIV infection have been recorded. In many countries the implementation of this prophylactic regimen is precluded because of limited resources and limited capacity to provide counselling, follow-up care and support.
WPR/RC49/6 page 14 Annex 2 One recent study in Thailand demonstrated that a short course of twice-daily oral AZT used from 36 weeks gestation until delivery reduced the risk for mother-to-child HIV transmission by approximately one half among women who do not breast-feed. AZT was not given to the new-born babies. This regimen may be useful for preventing HIV infection in children in countries with limited resources. Studies to assess the effectiveness of oral single or combination therapies among infants being breast-fed are underway, and the results are expected by September 1998. WHO has recently added AZT to the essential drugs list and the manufacturer is offering a substantial reduction in price for its use in reducing MTCT.
Essential requirements for use of antiretroviral agents A number of requirements need to be met before antiretroviral agents are introduced. The prevention, diagnosis and treatment of opportunistic infections (including the availability of affordable drugs for prophylaxis and treatment) remains an essential component of the clinical management of HIV/AIDS patients. Access to voluntary counselling and HIV testing (including preand post-test counselling) is also a prerequisite for antiretroviral therapies. Providing antiretroviral treatment implies organizing health services to ensure the sustainable provision of registered drugs, trained providers, basic laboratory facilities, regular clinical follow-up, and psychosocial support. Insufficiently supervised treatments and lack of adherence to eligibility criteria would not improve chances of survival. Instead, the probability of resistance would increase, thereby reducing treatment options for future drug regimens. The decision to introduce antiretroviral agents into a public health system also implies setting priorities within each country: − policy-makers have to determine the potential effect of antiretroviral treatments on overall health (which depends on the relative contribution of HIV/AIDS to the disease burden in each country); − the cost-effectiveness of antiretroviral treatments needs to be compared to the costeffectiveness of other HIV/AIDS interventions, such as education, controlling STDs, and safe blood supply;
WPR/RC49/6 page 15 Annex 2 − the various kinds of antiretroviral treatments (PEP, MTCT, treatment of HIV infections) and other treatment options should be considered, prioritized and implemented gradually. For MTCT, the identification of an effective and simple regime does not assure its successful use. Four factors that affect the affordability of interventions to prevent mother-to-child transmission are: (1) the cost of HIV tests (as all pregnant women would need to be counselled, and offered voluntary HIV testing); (2) the cost of antiretroviral drugs; (3) the cost of safe alternatives to breast-feeding; and (4) the cost of additional staff and consultations (counselling, clinical and social support).
Future of antiretroviral agents Several new drugs which are more potent, have fewer side effects and easier regimens are currently being developed and tested. Active research is also taking place in gene therapy to combat AIDS by boosting immune systems. Other research being carried out includes research on traditional medicine.
WPR/RC49/6 page 16 Annex 2 APPENDIX
WPR/RC49/6 page 17 Annex 2 Appendix
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WPR/RC49/6 page 19 ANNEX 3 Estimations for HIV prevalence in selected countries and areas of the Western Pacific Region (as of July 1998) Country/area Year HIV prevalence in adults (15–49) 120 000 66 000 86 000 4 200 300 3 100 11 000 3 100 1 300 23 000 400 000 1 000 3 100 6 800 HIV prevalence rate (%) in adults (15–49) 2.40 0.62 0.22 0.19 0.16 0.15 0.14 0.08 0.07 0.06 0.06 0.04 0.01 0.01 Women among HIV-infected population (%) 50 20 20 50 10 20 5 40 15 30 12 50 13 5 HIV exposure category Others Injecting Sexual (%) drug use contact (%) (%) 95 20 20 95 97 95 91 80 95 90 10 95 93 50 3 75 75 <1 <1 <1 5 15 3 <5 50 3 <1 <5 2 5 5 <5 3 5 4 5 2 6 40 2 7 46
Cambodia Malaysia Viet Nam Papua New Guinea Brunei Darussalam Singapore Australia Hong Kong New Zealand Philippines China Lao People’s Democratic Republic Republic of Korea Japan
1997 1997 1997 1997 1994 1997 1997 1997 1997 1997 1997 1997 1997 1997
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WPR/RC49/6 page 21 ANNEX 4
Estimations and projections of HIV prevalence and AIDS incidence among adults (15–49) in selected countries of the Western Pacific Region, 1997 Estimated 1997 Country Australia Brunei Darussalam (1994) Cambodia China Japan Lao PDR Malaysia New Zealand Papua New Guinea Philippines Republic of Korea Singapore Viet Nam Total a B
Projected 2000 HIV n/aa n/ab 160 000 1 200 000 n/aa n/ab 85 000 n/aa 10 500 38 000 n/aa n/ab 300 000 AIDS n/aa n/ab 9 000 33 000 n/aa n/ab 5 000 n/aa 670 1 780 n/aa n/ab 8 000
HIV 11 000 300 120 000 400 000 6 800 1 000 66 000 1 300 4 200 23 000 3 100 3 100 86 000 725 800
AIDS n/aa < 100 4 000 5 300 n/aa < 100 2 520 n/aa 480 650 n/aa < 100 2 000
Impact of antiretroviral treatments on HIV prevalence and AIDS incidence in the medium and long term unknown. Prevalence of HIV too low to make projections.
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WPR/RC49/6 page 23 ANNEX 5
Working estimations of prevalence and prevalence rates (adults >15 years) for selected STDs in selected countries in the Western Pacific Region, 1990s Country Gonorrhoea Prevalence Australia Brunei Darussalam Cambodia China Hong Kong Japan Malaysia Mongolia Papua New Guinea Philippines Republic of Korea Singapore Pacific Islands Viet Nam n.a. n.a. 177 000 1 365 000 2 342 n.a. 64 000 4 600 93 000 428 000 n.a. 4 200 9 000 239 000 (<1%) (<1%) (<1%) (<1%) (<1% (4%) (1%) (3%) (<1%) (<1%) Rate Syphilis Prevalence n.a. 1 400 236 000 n.a. 600 n.a. 128 000 8 000 93 000 214 000 52 500 3 800 180 000 143 000 (1%) (<1%) (4%) (<1%) (<1%) (<1%) (8%) (<1%) (<1%) (<1%) (4%) Rate Chlamydia Prevalence 709 000 n.a. 236 000 18 202 000 3 745 7 380 000 n.a. n.a. 533 000 2 560 000 n.a. 4 700 290 000 1 000 000 (<1%) (13%) (2%) (20%) (6%) (4%) (2%) (<1%) (7%) Rate (5%) Trichomoniasis Prevalence 59 000 n.a. n.a. n.a. 460 n.a. n.a. 6 200 n.a. 428 000 n.a. n.a. 248 000 n.a. (11%) (1%) (<1%) (<1%) Rate (<1%)
Note: All rates are calculated per population over 15 years of age. These are working estimations based on available information, and could be plus or minus 1%. n.a. indicates data not available