Global assessment of existing HIV and key population stigma indicators: A data mapping exercise to inform country-level stigma measurement.

BACKGROUND: Stigma is an established barrier to the provision and uptake of HIV prevention, diagnostic, and treatment services. Despite consensus on the importance of addressing stigma, there are currently no country-level summary measures to characterize stigma and track progress in reducing stigma around the globe. This data mapping exercise aimed to assess the potential for existing data to be used to summarize and track stigma, including discrimination, related to HIV status, or key population membership at the country level. METHODS AND FINDINGS: This study assessed existing indicators of stigma related to living with HIV or belonging to 1 of 4 key populations including gay men and other men who have sex with men, sex workers, people who use drugs, and transgender persons. UNAIDS Strategic Information Department led an initial drafting of possible domains, subdomains, and indicators, and a 3-week e-consultation was held to provide feedback. From the e-consultation, 44 indicators were proposed for HIV stigma; 14 for sexual minority stigma (including sexual behavior or orientation) related to men who have sex with men; 12 for sex work stigma; 10 for drug use stigma; and 17 for gender identity stigma related to transgender persons. We conducted a global data mapping exercise to identify and describe the availability and quality of stigma data across countries with the following sources: UNAIDS National Commitments and Policies Instrument (NCPI) database; Multiple Indicator Cluster Surveys (MICS); Demographic and Health Surveys (DHS); People Living with HIV Stigma Index surveys; HIV Key Populations Data Repository; Integrated Biological and Behavioral Surveys (IBBS); and network databases. Data extraction was conducted between August and November 2020. Indicators were evaluated based on the following: if an existing data source could be identified; the number of countries for which data were available for the indicator at present and in the future; variation in the indicator across countries; and considerations of data quality or accuracy. This mapping exercise resulted in the identification of 24 HIV stigma indicators and 10 key population indicators as having potential to be used at present in the creation of valid summary measures of stigma at the country level. These indicators may allow assessment of legal, societal, and behavioral manifestations of stigma across population groups and settings. Study limitations include potential selection bias due to available data sources to the research team and other biases due to the exploratory nature of this data mapping process. CONCLUSIONS: Based on the current state of data available, several indicators have the potential to characterize the level and nature of stigma affecting people living with HIV and key populations across countries and across time. This exercise revealed challenges for an empirical process reliant on existing data to determine how to weight and best combine indicators into indices. However, results for this study can be combined with participatory processes to inform summary measure development and set data collection priorities going forward.

Evaluating the quality of HIV epidemiologic evidence for populations in the absence of a reliable sampling frame: a modified quality assessment tool.

BACKGROUND: Sampling frames rarely exist for key populations at highest risk for HIV, such as sex workers, men who have sex with men, people who use drugs, and transgender populations. Without reliable sampling frames, most data collection relies on non-probability sampling approaches including network-based methods (e.g. respondent driven sampling) and venue-based methods (e.g. time-location sampling). Quality of implementation and reporting of these studies is highly variable, making wide-ranging estimates often difficult to compare. Here, a modified quality assessment tool, Global.HIV Quality Assessment Tool for Data Generated through Non-Probability Sampling (GHQAT), was developed to evaluate the quality of HIV epidemiologic evidence generated using non-probability methods. METHODS: The GHQAT assesses three main domains: study design, study implementation, and indicator-specific criteria(prevalence, incidence, HIV continuum of care, and population size estimates). The study design domain focuses primarily on the specification of the target and study populations. The study implementation domain is concerned with sampling implementation. Each indicator-specific section contains items relevant to that specific indicator. A random subset of 50 studies from a larger systematic review on epidemiologic data related to HIV and key populations was generated and reviewed using the GHQAT by two independent reviewers. Inter-rater reliability was assessed by calculating intraclass correlation coefficients for the scores assigned to study design, study implementation and each of the indicator-specific criteria. Agreement was categorized as poor(0.00-0.50), fair(0.51-0.70), and good(0.71-1.00). The distribution of good, fair, and poor scores for each section was described. RESULTS: Overall, agreement between the two independent reviewers was good(ICC >0.7). Agreement was best for the section evaluating the HIV continuum of care(ICC = 0.96). For HIV incidence, perfect agreement was observed, but this is likely due to the small number of studies reviewed that assessed incidence(n = 3). Of the studies reviewed, 2% (n = 1) received a score of "poor" for study design, while 50% (n = 25) received a score of "poor" for study implementation. CONCLUSIONS: Addressing HIV prevention and treatment needs of key populations is increasingly understood to be central to HIV responses across HIV epidemic settings, though data characterizing specific needs remains highly variable with the least amount of information in the most stigmatizing settings. Here, we present an efficient tool to guide HIV prevention and treatment programs as well as epidemiological data collection by reliably synthesizing the quality of available non-probability based epidemiologic information for key populations. This tool may help shed light on how researchers may improve not only the implementation of, but also the reporting on their studies.

Progress towards 2020 global HIV impact and treatment targets.

INTRODUCTION: Over the past 20 years, the response to the HIV epidemic has achieved remarkable results. These results have often been motivated by targets adopted by countries through United Nations (UN) Political Declarations on HIV. The 2016 political declaration included two impact targets, to achieve a 75% decline in new HIV infections and AIDS-related deaths between 2010 and 2020, and to reach the 90-90-90 testing and treatment targets by 2020. Our objective is to summarize progress towards these targets using robust and comparable HIV estimates released by UNAIDS in July 2021. In addition, we comment on the importance of targets and the modelled estimates required to quantify those targets. DISCUSSION: The UNAIDS estimates indicate that at the global and regional levels, the 2020 targets were missed: new infections declined by 31% and AIDS-related deaths declined by 47% between 2010 and 2020, compared to a target of 75% decline for both indicators. Similarly, no region achieved the 90-90-90 testing and treatment targets. Some countries, in diverse settings, achieved these targets showing that the targets were not overly ambitious if the right funding, policies and evidence-informed interventions at the right scale were in place. The 2021 UN Political Declaration on HIV, adopted on 8 June 2021, has set out a new set of ambitious but achievable targets for 2025. The 2025 targets and the required actions to reach those targets are described in the Global AIDS Strategy 2021-2026, which provides a framework to reprioritize HIV responses by reducing inequalities and building on the achievements of multiple Sustainable Development Goals. The Strategy encourages countries to monitor progress against targets for different geographic areas and populations to maximize equitable services and ensure accountability and also to understand why targets are being missed. CONCLUSIONS: The UNAIDS epidemiological estimates provide information that promote accountability and estimate progress towards global targets at the national level. Additional strategic information and analyses are required to identify the populations that are furthest from the targets and the programmes and policies that are keeping countries from meeting their targets.

Prevalence and burden of HBV co-infection among people living with HIV: A global systematic review and meta-analysis.

Globally, in 2017 35 million people were living with HIV (PLHIV) and 257 million had chronic HBV infection (HBsAg positive). The extent of HIV-HBsAg co-infection is unknown. We undertook a systematic review to estimate the global burden of HBsAg co-infection in PLHIV. We searched MEDLINE, Embase and other databases for published studies (2002-2018) measuring prevalence of HBsAg among PLHIV. The review was registered with PROSPERO (#CRD42019123388). Populations were categorized by HIV-exposure category. The global burden of co-infection was estimated by applying regional co-infection prevalence estimates to UNAIDS estimates of PLHIV. We conducted a meta-analysis to estimate the odds of HBsAg among PLHIV compared to HIV-negative individuals. We identified 506 estimates (475 studies) of HIV-HBsAg co-infection prevalence from 80/195 (41.0%) countries. Globally, the prevalence of HIV-HBsAg co-infection is 7.6% (IQR 5.6%-12.1%) in PLHIV, or 2.7 million HIV-HBsAg co-infections (IQR 2.0-4.2). The greatest burden (69% of cases; 1.9 million) is in sub-Saharan Africa. Globally, there was little difference in prevalence of HIV-HBsAg co-infection by population group (approximately 6%-7%), but it was slightly higher among people who inject drugs (11.8% IQR 6.0%-16.9%). Odds of HBsAg infection were 1.4 times higher among PLHIV compared to HIV-negative individuals. There is therefore, a high global burden of HIV-HBsAg co-infection, especially in sub-Saharan Africa. Key prevention strategies include infant HBV vaccination, including a timely birth-dose. Findings also highlight the importance of targeting PLHIV, especially high-risk groups for testing, catch-up HBV vaccination and other preventative interventions. The global scale-up of antiretroviral therapy (ART) for PLHIV using a tenofovir-based ART regimen provides an opportunity to simultaneously treat those with HBV co-infection, and in pregnant women to also reduce mother-to-child transmission of HBV alongside HIV.

Developing and implementing national health identifiers in resource limited countries: why, what, who, when and how?

Many resource-limited countries are scaling up health services and health-information systems (HISs). The HIV Cascade framework aims to link treatment services and programs to improve outcomes and impact. It has been adapted to HIV prevention services, other infectious and non-communicable diseases, and programs for specific populations. Where successful, it links the use of health services by individuals across different disease categories, time and space. This allows for the development of longitudinal health records for individuals and de-identified individual level information is used to monitor and evaluate the use, cost, outcome and impact of health services. Contemporary digital technology enables countries to develop and implement integrated HIS to support person centred services, a major aim of the Sustainable Development Goals. The key to link the diverse sources of information together is a national health identifier (NHID). In a country with robust civil protections, this should be given at birth, be unique to the individual, linked to vital registration services and recorded every time that an individual uses health services anywhere in the country: it is more than just a number as it is part of a wider system. Many countries would benefit from practical guidance on developing and implementing NHIDs. Organizations such as ASTM and ISO, describe the technical requirements for the NHID system, but few countries have received little practical guidance. A WHO/UNAIDS stake-holders workshop was held in Geneva, Switzerland in July 2016, to provide a 'road map' for countries and included policy-makers, information and healthcare professionals, and members of civil society. As part of any NHID system, countries need to strengthen and secure the protection of personal health information. While often the technology is available, the solution is not just technical. It requires political will and collaboration among all stakeholders to be successful.

The importance of assessing self-reported HIV status in bio-behavioural surveys.

In bio-behavioural surveys measuring prevalence of infection with human immunodeficiency virus (HIV), respondents should be asked the results of their last HIV test. However, many government authorities, nongovernmental organizations, researchers and other civil society stakeholders have stated that respondents involved in such surveys should not be asked to self-report their HIV status. The reasons offered for not asking respondents to report their status are that responses may be inaccurate and that asking about HIV status may violate the respondents' human rights and exacerbate stigma and discrimination. Nevertheless, we contend that, in the antiretroviral therapy era, asking respondents in bio-behavioural surveys to self-report their HIV status is essential for measuring and improving access to - and coverage of - services for the care, treatment and prevention of HIV infection. It is also important for estimating the true size of the unmet needs in addressing the HIV epidemic and for interpreting the behaviours associated with the acquisition and transmission of HIV infection correctly. The data available indicate that most participants in health-related surveys are willing to respond to a question about HIV status - as one of possibly several sensitive questions about sexual and drug use behaviours. Ultimately, normalizing the self-reporting of HIV status could help the global community move from an era of so-called exceptionalism to one of destigmatization - and so improve the epidemic response worldwide.

Dans les enquêtes bio-comportementales évaluant la prévalence de l'infection par le virus de l'immunodéficience humaine (VIH), il conviendrait de demander aux répondants le résultat de leur dernier test de dépistage du VIH. Mais nombre d'autorités gouvernementales, d'organisations non gouvernementales, de chercheurs et d'acteurs de la société civile sont défavorables à ce que l'on demande aux répondants de déclarer leur statut VIH dans ce type d'enquêtes. Parmi les raisons invoquées pour ne pas demander le statut VIH figure le fait que les réponses peuvent être inexactes et qu'une telle demande pourrait transgresser les droits humains des répondants et accentuer les problèmes de stigmatisation et de discrimination. Néanmoins, nous soutenons qu'aujourd'hui, à l'ère de la thérapie antirétrovirale, le fait de demander leur statut VIH aux répondants des enquêtes bio-comportementales est essentiel à des fins d'évaluation des services de soins, traitement et prévention de l'infection à VIH et pour en optimiser l'accès et la couverture. Cela est également fondamental pour évaluer la véritable ampleur des besoins non satisfaits dans la gestion de l'épidémie de VIH et pour correctement interpréter les comportements associés à l'acquisition et à la transmission du VIH. Les données disponibles indiquent que la plupart des participants aux enquêtes liées à la santé acceptent de répondre à une question sur leur statut VIH, parmi d'autres questions sensibles concernant les comportements sexuels et l'usage de drogues. Enfin, une normalisation de l'auto-déclaration du statut VIH pourrait aider la communauté mondiale à dépasser ce que l'on appelle « l'exceptionnalisme ¼ pour ouvrir une ère de déstigmatisation, ce qui permettrait d'améliorer la réponse face à l'épidémie dans le monde entier.

Durante la realización de encuestas bioconductuales que miden la prevalencia del contagio del virus de la inmunodeficiencia humana (VIH), los encuestados deberían entregar los resultados de la última prueba de VIH a la que se hayan sometido. No obstante, muchas autoridades gubernamentales, organizaciones no gubernamentales, investigadores y otras partes interesadas de la sociedad civil han declarado que las personas encuestadas implicadas en dichas encuestas no deberían tener que realizar una autodeclaración de su estado con relación al VIH. Las razones expuestas para no pedir a los encuestados que informen de su condición son que las respuestas pueden ser inexactas y que preguntarles por su estado en relación al VIH puede violar sus derechos humanos y exacerbar la estigmatización y la discriminación. Sin embargo, se sostiene que, en la era de terapias antirretrovirales, solicitar a los encuestados en encuestas bioconductuales que declaren su estado en relación al VIH es fundamental para medir y mejorar el acceso a, y la cobertura de, servicios para la atención, el tratamiento y la prevención del contagio del VIH. También es importante para estimar el verdadero alcance de las necesidades insatisfechas a la hora de abordar la epidemia de VIH, así como para interpretar las conductas asociadas a la adquisición y transmisión del virus de forma adecuada. Los datos disponibles indican que la mayor parte de los participantes en encuestas relacionadas con la salud están dispuestos a responder una pregunta sobre su estado en relación al VIH como una de las muchas posibles preguntas delicadas sobre comportamientos sexuales y de consumo de drogas. Por último, normalizar las declaraciones sobre el estado en relación al VIH podría ayudar a la comunidad mundial a pasar de una época caracterizada por el "excepcionalismo" a una caracterizada por la "desestigmatización", y, de este modo, mejorar la respuesta frente a las epidemias a nivel mundial.

Availability and Quality of Size Estimations of Female Sex Workers, Men Who Have Sex with Men, People Who Inject Drugs and Transgender Women in Low- and Middle-Income Countries.

OBJECTIVE: To 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. METHODS: Size 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.' FINDINGS: Of 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. CONCLUSIONS: Size 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.

Male sex workers: practices, contexts, and vulnerabilities for HIV acquisition and transmission.

Male sex workers who sell or exchange sex for money or goods encompass a very diverse population across and within countries worldwide. Information characterising their practices, contexts where they live, and their needs is limited, because these individuals are generally included as a subset of larger studies focused on gay men and other men who have sex with men (MSM) or even female sex workers. Male sex workers, irrespective of their sexual orientation, mostly offer sex to men and rarely identify as sex workers, using local or international terms instead. Growing evidence indicates a sustained or increasing burden of HIV among some male sex workers within the context of the slowing global HIV pandemic. Several synergistic facilitators could be potentiating HIV acquisition and transmission among male sex workers, including biological, behavioural, and structural determinants. Criminalisation and intersectional stigmas of same-sex practices, commercial sex, and HIV all augment risk for HIV and sexually transmitted infections among male sex workers and reduce the likelihood of these people accessing essential services. These contexts, taken together with complex sexual networks among male sex workers, define this group as a key population underserved by current HIV prevention, treatment, and care services. Dedicated efforts are needed to make those services available for the sake of both public health and human rights. Evidence-based and human rights-affirming services dedicated specifically to male sex workers are needed to improve health outcomes for these men and the people within their sexual networks.

Updates to the spectrum model to estimate key HIV indicators for adults and children.

BACKGROUND: The Spectrum program is used to estimate key HIV indicators for national programmes. The purpose of the study is to describe the key updates made to Spectrum in the last 2 years to produce the version used in the 2013 global estimates of HIV/AIDS. METHODS: The United Nations Programme on HIV/AIDS (UNAIDS) Reference Group on Estimates, Models and Projections regularly reviews new data and information needs and recommends updates to the methodology and assumptions used in Spectrum. The latest data from surveys, census and special studies are used to estimate key parameter values for countries and regions. RESULTS: Country-specific life tables prepared by the United National Population Division (UNPD) have been incorporated into Spectrum's demographic projections replacing the model life tables used previously. This update includes revised estimates of non-AIDS life expectancy. Incidence among all adults 15-49 years generated from curve fitting to surveillance and survey data is now split by age using incidence rate ratios derived from Analysing Longitudinal Population-based HIV/AIDS data on Africa Network data for generalized epidemics. Methods for estimating the number of AIDS orphans have been updated to include the changing effects of PMTCT and antiretroviral therapy programmes. Procedures for estimating the number of adults eligible for treatment have been updated to reflect the 2013 WHO guidelines. Program data on AIDS mortality has been used to estimate prevalence trends in Argentina, Brazil and Mexico for the 2013 estimates. CONCLUSION: Spectrum was updated for the 2013 round of HIV estimates in order to support national programmes with improved methods and data to estimating national indicators.

Epidemiological challenges to the assessment of HIV burdens among key populations: respondent-driven sampling, time-location sampling and demographic and health surveys.

PURPOSE OF REVIEW: Measuring the burden of HIV among key populations is subject to many challenges. Sufficient quantities of valid HIV prevalence and programme coverage data are required to effectively respond to the epidemic. RECENT FINDINGS: Ability to validate exposure to unprotected sex through the innovative use of prostate-specific antigen provides confirmation of condom use. A new weighting scheme based on frequency of venue attendance for time location samples should improve validity of data obtained with this method. Two new proportion estimators, new diagnostic methods, a new population size estimator and new analysis software will provide more robust results from respondent-driven sampling (RDS). SUMMARY: Analytical advances have improved the potential quality of results from surveys using time location and RDS. However, data from sufficient numbers of sites over sufficient number of years are still needed to provide clear national pictures of distribution and trends of HIV infection.

The potential impact of expanding antiretroviral therapy and combination prevention in Vietnam: towards elimination of HIV transmission.

BACKGROUND: Few studies have assessed the effects of antiretroviral therapy (ART) to prevent HIV transmission in Asian HIV epidemics. Vietnam has a concentrated HIV epidemic with the highest prevalence among people who inject drugs. We investigated the impact of expanded HIV testing and counseling (HTC) and early ART, combined with other prevention interventions on HIV transmission. METHODS: A deterministic mathematical model was developed using HIV prevalence trends in Can Tho province, Vietnam. Scenarios included offering periodic HTC and immediate ART with and without targeting subpopulations and examining combined strategies with methadone maintenance therapy and condom use. RESULTS: From 2011 to 2050, maintaining current interventions will incur an estimated 18,115 new HIV infections and will cost US $22.1 million (reference scenario). Annual HTC and immediate treatment, if offered to all adults, will reduce new HIV infections by 14,513 (80%) and will cost US $76.9 million. Annual HTC and immediate treatment offered only to people who inject drugs will reduce new infections by 13,578 (75%) and will cost only US $23.6 million. Annual HTC and immediate treatment for key populations, combined with scale-up of methadone maintenance therapy and condom use, will reduce new infections by 14,723 (81%) with similar costs (US $22.7 million). This combination prevention scenario will reduce the incidence to less than 1 per 100,000 in 14 years and will result in a relative cost saving after 19 years. CONCLUSIONS: Targeted periodic HTC and immediate ART combined with other interventions is cost-effective and could lead to potential elimination of HIV in Can Tho.

HIV testing behaviors among undocumented Central American immigrant women in Houston, Texas.

This paper describes HIV testing behaviors among undocumented Central American immigrant women living in Houston, Texas, USA. Respondent driven sampling was used to recruit participants for an HIV behavioral survey. HIV testing items included lifetime history of testing, date and location of the most recent test, and reason for testing. Multivariate logistic regression was used to assess the demographic, behavioral, and structural characteristics associated with testing. The lifetime prevalence of HIV testing was 67%. Half of those who tested did so within the past 2 years and almost 80% received their most recent test in a healthcare setting. The primary reason for testing was pregnancy. Lifetime testing was associated with being from Honduras, having over a sixth grade education, having a regular healthcare provider, and having knowledge of available healthcare resources. Our results suggest that expanding access to healthcare services may increase the prevalence of HIV testing in this population.

Bridging populations-sexual risk behaviors and HIV prevalence in clients and partners of female sex workers, Bangkok, Thailand 2007.

The aim of this study is to estimate HIV prevalence and assess sexual behaviors in a high-risk and difficult-to-reach population of clients of female sex workers (FSWs). A modified variation of respondent-driven sampling was conducted among FSWs in Bangkok, where FSWs recruited 3 FSW peers, 1 client, and 1 nonpaying partner. After informed consent was obtained, participants completed a questionnaire, were HIV-tested, and were asked to return for results. Analyses were weighted to control for the design of the survey. Among 540 FSWs, 188 (35%) recruited 1 client, and 88 (16%) recruited 1 nonpaying partner. Clients' median age was 38 years. HIV prevalence was 20% and was associated with younger age at first sexual experience [relative risk (RR) = 3.10, 95% confidence interval (CI) 1.16-8.24] and condom use during last sexual encounter with regular partner (RR = 3.97, 95% CI 1.09-14.61). Median age of nonpaying partners was 34 years, and HIV prevalence was 15.1%. There were 56 discordant FSW-client pairs and 14 discordant FSW-nonpaying partner pairs. Condom use was relatively high among discordant FSW-client pairs (90.1%) compared to discordant FSW-nonpaying partner pairs (18.7%). Results suggest that sexual partners of FSWs have a high HIV prevalence and can be a bridge for HIV transmission to other populations. Findings also highlight the importance of initiating surveillance and targeted programs for FSW partners, and demonstrate a recruitment method for hard-to-reach populations.

Assessment of respondent driven sampling for recruiting female sex workers in two Vietnamese cities: reaching the unseen sex worker.

Respondent driven sampling (RDS) is a relatively new method to sample hard-to-reach populations. Until this study, female sex workers (FSWs) in Vietnam were sampled using a variety of methods, including time location sampling (TLS), which may not access the more hidden types of FSWs. This paper presents an analysis from an HIV biological and behavioral surveillance survey to assess the feasibility and effectiveness of RDS to sample FSWs, to determine if RDS can reach otherwise inaccessible FSWs in Vietnam and to compare RDS findings of HIV risk factors with a theoretical TLS. Through face-to-face interviews with FSWs in Ho Chi Minh City (HCMC) and Hai Phong (HP), data were collected about the venues where they most often solicit their clients. These data were used to create three variables to assess whether FSWs solicit their clients in locations that are visible, semi-visible and non-visible. For this analysis, the visible group simulates a sample captured using TLS. Survey results in HIV prevalence and related risk factors and service utilization, adjusted for sampling methodology, were compared across each of the three FSW visibility groups to assess potential bias in TLS relative to RDS. The number of self-reported visible FSWs (HCMC: n=311; HP: n=162) was much larger than those of the semi-visible (HCMC: n=65; HP: n=43) and non-visible (HCMC: n=37; HP: n=10) FSWs in HCMC and HP. Non-visible FSWs in both cities were just as likely as visible and semi-visible FSWs to be HIV positive (HCMC: visible 14.5%, semi-visible 13.8%, non-visible 13.5%, p value = 0.982; HP: visible 35.2%, semi-visible 30.2%, non-visible 30.0%, p value = 0.801), to practice behaviors that put them at risk for contracting and transmitting HIV (injecting drug use-HCMC: visible 13.8%, semi-visible 12.3%, non-visible 5.4%, p value = 0.347; HP: visible 38.9%, semi-visible 23.3%, non-visible 30.0%, p value = 0.378, to have no condom use in the past month -HCMC only: visible 52.7%, semi-visible 63.1%, non-visible 48.6%, p value = 0.249) and to have symptoms of a sexually transmitted infection (STI) in the past year (HCMC: visible 16.1%, semi-visible 12.3%, non-visible 16.2%, p value = 0.742; HP: visible 13.6%, semi-visible 18.6%, non-visible 20.0%, p value = 0.640). There was a difference found among the visible, semi-visible and non-visible groups in HP for no past month condom use (visible 53.1%, semi-visible 79.1%, non-visible 60.0%, p value = 0.009). This study found that RDS was successful at recruiting hidden types of FSWs in Vietnam. Past reports of FSWs in Vietnam have assessed the more visible FSWs as being the most vulnerable and at risk for HIV. Although the number of visible FSWs is much higher than those of the semi and non-visible groups, this study found that the non-visible FSWs are very vulnerable to HIV infection. If prevention programs are targeting and responding to those who are most likely to be assessed (e.g., more visible types of FSWs) then this analysis indicates that a significant proportion of the FSW population at risk for HIV may not be receiving optimal HIV information and services.