ObjectiveTo assess the availability and quality of population size estimations of female sex workers (FSW), men who have sex with men (MSM), people who inject drug (PWID) and transgender women.MethodsSize estimation data since 2010 were retrieved from global reporting databases, Global Fund grant application documents, and the peer-reviewed and grey literature. Overall quality and availability were assessed against a defined set of criteria, including estimation methods, geographic coverage, and extrapolation approaches. Estimates were compositely categorized into ‘nationally adequate’, ‘nationally inadequate but locally adequate’, ‘documented but inadequate methods’, ‘undocumented or untimely’ and ‘no data.’FindingsOf 140 countries assessed, 41 did not report any estimates since 2010. Among 99 countries with at least one estimate, 38 were categorized as having nationally adequate estimates and 30 as having nationally inadequate but locally adequate estimates. Multiplier, capture-recapture, census and enumeration, and programmatic mapping were the most commonly used methods. Most countries relied on only one estimate for a given population while about half of all reports included national estimates. A variety of approaches were applied to extrapolate from sites-level numbers to national estimates in two-thirds of countries.ConclusionsSize estimates for FSW, MSM, PWID and transgender women are increasingly available but quality varies widely. The different approaches present challenges for data use in design, implementation and evaluation of programs for these populations in half of the countries assessed. Guidance should be further developed to recommend: a) applying multiple estimation methods; b) estimating size for a minimum number of sites; and, c) documenting extrapolation approaches.

Background: HIV programmes in sub-Saharan Africa (SSA) require information about HIV among key populations to ensure equitable and equal access to HIV prevention and treatment. Surveillance has been conducted among female sex workers (FSW), men who have sex with men (MSM), people who inject drugs (PWID), and transgender populations, but is not systematically included in national HIV estimates. We consolidated existing KP surveys to create national-level estimates of key population size, HIV prevalence, and ART coverage for mainland SSA. Methods: Key population size estimates (KPSE), HIV prevalence, and ART coverage data from 38 countries from 2010-2021 were collated from existing databases, deduplicated, and verified against primary sources. We used Bayesian mixed-effects regression to spatially smooth KPSE, and regressed subnational key population HIV prevalence and ART coverage against age/sex/year/province-matched total population estimates. Findings: We extracted 1449 unique KPSE datapoints, 1181 HIV prevalence datapoints, and 242 ART coverage datapoints. Countries had data for a median of five of the twelve population/outcome stratifications. Across countries, a median of 1.44% of urban women were FSW (interquartile range [IQR] 0.83-1.89%); 0.60% of urban men were MSM; and 0.16% of urban adults injected drugs (IQR 0.14-0.24%). HIV prevalence in all key populations was higher than matched total population prevalence. ART coverage was correlated with, but lower than, total population ART coverage. Across SSA, key populations were estimated as 1.1% (95%CI 0.7-1.9%) of the population but 5.1% (95%CI 3.2-10.3%) of all PLHIV aged 15-49 years. Interpretation: Key populations in sub-Saharan experience disproportionate HIV burden and somewhat lower ART coverage, underscoring need for focused prevention and treatment services. However, large heterogeneity and incomplete data availability limit precise estimates for programming and monitoring trends. Future efforts should focus on integrating and strengthening key population surveys and routine data within national HIV strategic information systems.

Background In 2019, 62% of new HIV infections occurred among key populations (KPs) and their sexual partners. The World Health Organization (WHO) recommends implementation of bio-behavioral surveys every 2-3 years to obtain HIV prevalence data for all KPs. However, the collection of these data is often less frequent and geographically limited. Objective This study intended to assess the availability and quality of HIV prevalence data among sex workers (SWs), men who have sex with men (MSM), people who inject drugs, and transgender women (transwomen) in low- and middle-income countries. Methods Data were obtained from survey reports, national reports, journal articles, and other grey literature available to the Global Fund, Joint United Nations Programme on HIV/AIDS, and WHO or from other open sources. Elements reviewed included names of subnational units, HIV prevalence, sampling method, and size. Based on geographical coverage, availability of trends over time, and recency of estimates, data were categorized by country and grouped as follows: nationally adequate, locally adequate but nationally inadequate, no recent data, no trends available, and no data. Results Among the 123 countries assessed, 91.9% (113/123) presented at least 1 HIV prevalence data point for any KP; 78.0% (96/123) presented data for at least 2 groups; and 51.2% (63/123), for at least 3 groups. Data on all 4 groups were available for only 14.6% (18/123) of the countries. HIV prevalence data for SWs, MSM, people who inject drugs, and transwomen were available in 86.2% (106/123), 80.5% (99/123), 45.5% (56/123), and 23.6% (29/123) of the countries, respectively. Only 10.6% (13/123) of the countries presented nationally adequate data for any KP between 2001 and 2017; 6 for SWs; 2 for MSM; and 5 for people who inject drugs. Moreover, 26.8% (33/123) of the countries were categorized as locally adequate but nationally inadequate, mostly for SWs and MSM. No trend data on SWs and MSM were available for 38.2% (47/123) and 43.9% (54/123) of the countries, respectively, while no data on people who inject drugs and transwomen were available for 76.4% (94/123) and 54.5% (67/123) of the countries, respectively. An increase in the number of data points was observed for MSM and transwomen. Overall increases were noted in the number and proportions of data points, especially for MSM, people who inject drugs, and transwomen, with sample sizes exceeding 100. Conclusions Despite general improvements in health data availability and quality, the availability of HIV prevalence data among the most vulnerable populations in low- and middle-income countries remains insufficient. Data collection should be expanded to include behavioral, clinical, and epidemiologic data through context-specific differentiated survey approaches while emphasizing data use for program improvements. Ending the HIV epidemic by 2030 is possible only if the epidemic is controlled among KPs.

There was no global guidance or agreement regarding when a country has an adequate system to report on the service packages among human immunodeficiency virus (HIV) key populations. This article describes an approach to categorizing the system in a country for reporting the service package among HIV key populations. The approach consists of four dimensions, namely the epidemiological significance, comprehensiveness of the service packages, geographic coverage of services, and adequacy of the monitoring system. The proposed categorization approach utilizes available information and can inform the improvement of the service delivery and monitoring systems among HIV key populations. Electronic supplementary material The online version of this article (10.1186/s40249-019-0570-4) contains supplementary material, which is available to authorized users.

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