Maximizing the benefits of antiretroviral therapy for key affected populations

INTRODUCTION

Scientific research has demonstrated the clinical benefits of earlier initiation of antiretroviral treatment (ART), and that ART can markedly reduce HIV transmission to sexual partners. Ensuring universal access to ART for those who need it has long been a core principle of the HIV response, and extending the benefits of ART to key populations is critical to increasing the impact of ART and the overall effectiveness of the HIV response. However, this can only be achieved through coordinated efforts to address political, social, legal and economic barriers that key populations face in accessing HIV services.

DISCUSSION

Recent analyses show that HIV prevalence levels among key populations are far higher than among the general population, and they experience a range of biological and behavioural factors, and social, legal and economic barriers that increase their vulnerability to HIV and have resulted in alarmingly low ART coverage. World Health Organization 2014 consolidated guidance on HIV among key populations offers the potential for increased access to ART by key populations, following the same principles as for the general adult population. However, it should not be assumed that key populations will achieve greater access to ART unless stigma, discrimination and punitive laws, policies and practices that limit access to ART and other HIV interventions in many countries are addressed.

CONCLUSIONS

Rights-based approaches and investments in critical enablers, such as supportive legal and policy environments, are essential to enable wider access to ART and other HIV interventions for key populations. The primary objective of ART should always be to treat the person living with HIV; prevention is an important, additional benefit. ART should be provided only with informed consent. The preventive benefits of treatment must not be used as a pretext for failure to provide other necessary HIV programming for key populations, including comprehensive harm reduction and other prevention interventions tailored to meet the needs of key populations. An end to AIDS is only possible if we overcome the barriers of criminalization, stigma and discrimination that remain key drivers of the HIV epidemics among key populations.

A qualitative assessment of health seeking practices among and provision practices for men who have sex with men in Malawi

BACKGROUND

In the context of a generalized epidemic and criminalization of homosexuality, men who have sex with men (MSM) in Malawi have a disproportionate burden of HIV compared to other adults. Past research has documented low uptake of HIV prevention and health services among MSM, self-reported fear of seeking health services, and concerns of disclosure of sexual orientation and discrimination in health settings. Qualitative research was conducted among MSM and health service providers in Blantyre, Malawi to understand underlying factors related to disclosure and health seeking behaviors and inform the development of a community-based comprehensive HIV prevention intervention.

METHODS

Using peer recruitment, eight MSM participants representing a range of ages, orientations, and social and behavioral characteristics were enrolled for in-depth interviews. Five service providers were recruited from the district hospital, local health and STI clinics, and a HIV prevention service organization. We use the Health Belief Model as a framework to interpret the influential factors on 1) health seeking and uptake among MSM, and 2) influences on provision of services by healthcare providers for MSM.

RESULTS

Results highlight disclosure fears among MSM and, among providers, a lack of awareness and self-efficacy to provide care in the face of limited information and political support. Service providers reported concerns of adverse repercussions related to the provision of services to men in same sex sexual relationships. Some MSM demonstrated awareness of HIV risk but believed that within the wider MSM community, there was a general lack of HIV information for MSM, low awareness of appropriate prevention, and low perception of risks related to HIV infection.

CONCLUSIONS

Qualitative research highlights the need for appropriate information on both HIV risks and acceptable, effective HIV prevention options for MSM. Information and educational opportunities should be available to the wider MSM community and the health sector. Health sector interventions may serve to increase cultural and clinical competency to address health problems experienced by MSM. To ensure availability and use of services in light of the criminalization and stigmatization of same sex practices, there is need to increase the safety of uptake and provision of these services for MSM.

Pushback: the current wave of anti-homosexuality laws and impacts on health

Chris Beyrer discusses the worrying global trend towards the increasing criminalization of homosexuality. Please see later in the article for the Editors' Summary

Systematic review and meta-analysis of HIV prevalence among men in militaries in low income and middle income countries

OBJECTIVES

To determine whether the current HIV prevalence in militaries of low-income and middle-income countries is higher, the same, or lower than the HIV prevalence in the adult male population of those countries.

METHODS

HIV prevalence data from low-income and middle-income countries' military men were systematically reviewed during 2000-2012 from peer reviewed journals, clearing-house databases and the internet. Standardised data abstraction forms were used to collect information on HIV prevalence, military branch and sample size. Random effects meta-analyses were completed with the Mantel-Haenszel method comparing HIV prevalence among military populations with other men in each country.

RESULTS

2214 studies were retrieved, of which 18 studies representing nearly 150000 military men across 11 countries and 4 regions were included. Military male HIV prevalence across the studies ranged from 0.06% (n=22666) in India to 13.8% (n=2733) in Tanzania with a pooled prevalence of 1.1% (n=147591). HIV prevalence in male military populations in sub-Saharan Africa was significantly higher when compared with reproductive age (15-49 years) adult men (OR: 2.8, 95% CI 1.01 to 7.81). HIV prevalence in longer-serving male military populations compared with reproductive age adult men was significantly higher (OR: 2.68, 95% CI 1.65 to 4.35).

CONCLUSIONS

Our data reveals that across the different settings, the burden of HIV among militaries may be higher or lower than the civilian male populations. In this study, male military populations in sub-Saharan Africa, low-income countries and longer-serving men have significantly higher HIV prevalence. Given the national security implications of the increased burden of HIV, interventions targeting military personnel in these populations should be scaled up where appropriate.

The Prevalence of Sexual Violence among Female Refugees in Complex Humanitarian Emergencies: a Systematic Review and Meta-analysis

Importance: Refugees and internally displaced persons are highly vulnerable to sexual violence during conflict and subsequent displacement. However, accurate estimates of the prevalence of sexual violence among in these populations remain uncertain. Objective: Our objective was to estimate the prevalence of sexual violence among refugees and displaced persons in complex humanitarian emergencies. Data Source: We conducted systematic review of relevant literature in multiple databases (EMBASE, CINAHL, and MEDLINE) through February 2013 to identify studies. We also reviewed reference lists of included articles to identify any missing sources. Study Selection: Inclusion criteria required identification of sexual violence among refugees and internally displaced persons or those displaced by conflict in complex humanitarian settings. Studies were excluded if they did not provide female sexual violence prevalence, or that included only single case reports, anecdotes, and those that focused on displacement associated with natural disasters. After a review of 1175 citations 19 unique studies were selected. Data Extraction: Two reviewers worked independently to identify final selection and a third reviewer adjudicated any differences. Descriptive and quantitative information was extracted; prevalence estimates were synthesized. Heterogeneity was assessed using I2. Main Outcomes: The main outcome of interest was sexual violence among female refugees and internally displaced persons in complex humanitarian settings. Results: The prevalence of sexual violence was estimated at 21.4% (95% CI, 14.9-28.7; I2=98.3%), using a random effects model. Statistical heterogeneity was noted with studies using probability sampling designs reporting lower prevalence of sexual violence (21.0%, 95% CI, 13.2-30.1; I2=98.6%), compared to lower quality studies (21.7%, 95% CI, 11.5-34.2; I2=97.4%). We could not rule out the presence of publication bias. Conclusions: The findings suggest that approximately one in five refugees or displaced women in complex humanitarian settings experienced sexual violence. However, this is likely an underestimation of the true prevalence given the multiple existing barriers associated with disclosure. The long-term health and social consequences of sexual violence for women and their families necessitate strategies to improve identification of survivors of sexual violence and increase prevention and response interventions in these complex settings.

The role of viral introductions in sustaining community-based HIV epidemics in rural Uganda: evidence from spatial clustering, phylogenetics, and egocentric transmission models

BACKGROUND

It is often assumed that local sexual networks play a dominant role in HIV spread in sub-Saharan Africa. The aim of this study was to determine the extent to which continued HIV transmission in rural communities--home to two-thirds of the African population--is driven by intra-community sexual networks versus viral introductions from outside of communities.

METHODS AND FINDINGS

We analyzed the spatial dynamics of HIV transmission in rural Rakai District, Uganda, using data from a cohort of 14,594 individuals within 46 communities. We applied spatial clustering statistics, viral phylogenetics, and probabilistic transmission models to quantify the relative contribution of viral introductions into communities versus community- and household-based transmission to HIV incidence. Individuals living in households with HIV-incident (n = 189) or HIV-prevalent (n = 1,597) persons were 3.2 (95% CI: 2.7-3.7) times more likely to be HIV infected themselves compared to the population in general, but spatial clustering outside of households was relatively weak and was confined to distances <500 m. Phylogenetic analyses of gag and env genes suggest that chains of transmission frequently cross community boundaries. A total of 95 phylogenetic clusters were identified, of which 44% (42/95) were two individuals sharing a household. Among the remaining clusters, 72% (38/53) crossed community boundaries. Using the locations of self-reported sexual partners, we estimate that 39% (95% CI: 34%-42%) of new viral transmissions occur within stable household partnerships, and that among those infected by extra-household sexual partners, 62% (95% CI: 55%-70%) are infected by sexual partners from outside their community. These results rely on the representativeness of the sample and the quality of self-reported partnership data and may not reflect HIV transmission patterns outside of Rakai.

CONCLUSIONS

Our findings suggest that HIV introductions into communities are common and account for a significant proportion of new HIV infections acquired outside of households in rural Uganda, though the extent to which this is true elsewhere in Africa remains unknown. Our results also suggest that HIV prevention efforts should be implemented at spatial scales broader than the community and should target key populations likely responsible for introductions into communities.

Female sex workers in three cities in Russia: HIV prevalence, risk factors and experience with targeted HIV prevention

Within Eastern Europe/Central Asia's expanding HIV epidemic, relatively little is known about female sex workers (FSWs). Using mixed methods, we report on sex work context, HIV prevalence and contextual risk factors, and exposure to FSW-targeted prevention services among FSWs in Kazan, Krasnoyarsk, and Tomsk, Russia. Following a qualitative phase, FSWs (n = 754) were recruited via respondent-driven sampling for a cross-sectional survey with HIV screening in 2011. HIV was prevalent (3.9 %). In adjusted analyses, significant risk factors included injection drug use (IDU; AOR 5.85, 95 % CI 2.47, 14.43), client-perpetrated physical violence (AOR 2.52, 95 % CI 1.41, 4.51), and client-perpetrated sexual violence (vaginal AOR 3.77, 95 % CI 1.73, 8.22; anal AOR 4.80, 95 % CI 1.89, 12.19). FSW-targeted programming (reported by 75 %) was described as highly valuable, providing free, anonymous, and non-stigmatizing care. Findings confirm FSWs as a core HIV risk population in Russia, and demonstrate the need to support FSW-oriented HIV services. Such efforts should address violence against FSWs.

Epidemic impacts of a community empowerment intervention for HIV prevention among female sex workers in generalized and concentrated epidemics

Introduction

Sex workers have endured a high burden of HIV infection in and across HIV epidemics. A comprehensive, community empowerment-based HIV prevention intervention emphasizes sex worker organization and mobilization to address HIV risk and often includes community-led peer education, condom distribution, and other activities. Meta-analysis of such interventions suggests a potential 51% reduction in inconsistent condom use. Mathematical modeling exercises provide theoretical insight into potential impacts of the intervention on HIV incidence and burden in settings where interventions have not yet been implemented.

Methods

We used a deterministic model, Goals, to project the impact on HIV infections when the community empowerment interventions were scaled up among female sex workers in Kenya, Thailand, Brazil, and Ukraine. Modeling scenarios included expansion of the comprehensive community empowerment-based HIV prevention intervention from baseline coverage over a 5-year period (5–65% in Kenya and Ukraine; 10–70% in Thailand and Brazil), while other interventions were held at baseline levels. A second exercise increased the intervention coverage simultaneously with equitable access to ART for sex workers. Impacts on HIV outcomes among sex workers and adults are observed from 2012–2016 and, compared to status quo when all interventions are held constant.

Results

Optimistic but feasible coverage (65%–70%) of the intervention demonstrated a range of impacts on HIV: 220 infections averted over 5 yrs. among sex workers in Thailand, 1,830 in Brazil, 2,220 in Ukraine, and 10,800 infections in Kenya. Impacts of the intervention for female sex workers extend to the adult population, cumulatively averting 730 infections in Thailand to 20,700 adult infections in Kenya. Impacts vary by country, influenced by HIV prevalence in risk groups, risk behaviors, intervention use, and population size.

Discussion

A community empowerment approach to HIV prevention and access to universal ART for female sex workers is a promising human rights-based solution to overcoming the persistent burden of HIV among female sex workers across epidemic settings.

Sexual practices, identities and health among women who have sex with women in Lesotho - a mixed-methods study

Despite the high prevalence of HIV and STIs among women in Africa and the growing literature on HIV and STIs among women who have sex with women, research on the sexual health of women who have sex with women in Africa is scant. This study used mixed methods to describe sexual identity, practices and health among women who have sex with women in Lesotho. Most respondents (48%) described themselves as lesbian, 29% as bisexual and 23% as heterosexual. Almost half (45%) had disclosed their same-sex attraction to family, but only 25% had done so with healthcare workers. A total of 8% reported having HIV. Self-reported HIV was associated with having three or more male partners, having male and female partners at the same time and having a history of STIs. Gender norms, the criminalisation of homosexuality, varied knowledge of, and access to, safer-sex strategies, and mixed experiences of HIV/STI testing and sexual healthcare provided social and structural contexts for HIV- and STI-related vulnerability.

Uncovering the epidemic of HIV among men who have sex with men in Central Asia

BACKGROUND

Research among people who inject drugs (PWID) in Central Asia has described same sex behavior among male PWID and may be associated with HIV and other infections. Little is known about the population of men who have sex with men (MSM) and the burden of HIV among MSM in Central Asian countries.

METHODS

We conducted a comprehensive search of peer-reviewed publications and gray literature on MSM and HIV in the region. Search strategies included terms for MSM combined with five Central Asian countries and neighbors, including Mongolia, Afghanistan, and Xinjiang Province, China.

RESULTS

230 sources were identified with 43 eligible for inclusion: 12 provided HIV prevalence and population size estimates for MSM, none provided incidence estimates, and no publications for Turkmenistan were identified. National reports estimate HIV prevalence among MSM to range from 1 to 2% in Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan, Xinjiang, to 10% in Mongolia. Biobehavioral studies estimated HIV prevalence at 0.4% in Afghanistan and 20.2% in Kazakhstan. Sexual identities and behaviors vary across countries. Injection drug use was relatively low among MSM (<5% for most). Non-injection drugs, alcohol use prior to sex, and binge drinking were more common and potentially associated with violence. Criminalization of homosexuality (Afghanistan, Uzbekistan, and Turkmenistan) and stigma has limited research and HIV prevention.

CONCLUSION

Improved understanding of risks, including potential linkages between sexual exposures and substance use, among MSM are important for response. The little known about HIV among MSM in Central Asia speaks to the urgency of improvements in HIV research, prevention, and care.

Acceptability of pre-exposure prophylaxis among men who have sex with men and transgender women in Northern Thailand

Background

Northern Thailand has a high burden HIV epidemic among MSM and TG. Oral pre-exposure prophylaxis (PrEP) with tenofovir-emtricitabine has demonstrated efficacy in preventing HIV among MSM and TG in Chiang Mai, Thailand. Determinants of PrEP acceptability are needed to gauge the potential uptake of this prevention strategy.

Methods

From January to February 2012, 238 MSM and TG participants, who self-reported as HIV-uninfected or of unknown status, completed a self-administered survey on hand-held computers. Participants were recruited by venue-day-time sampling and asked to rate their likelihood of using oral PrEP for HIV prevention with an efficacy of 50%. PrEP acceptability was defined as being “very likely” to use PrEP. Odds ratios and 95% CIs were calculated to identify correlates of acceptability.

Results

131 MSM and 107 TG responded, with mean ages of 23.7 and 21.8, respectively. 24% of MSM engaged primarily in receptive anal sex vs. 74% of TG. 21% of MSM and 44% of TG reported regular medication use. Prior awareness of PrEP was high at 66% among both MSM and TG respondents. 41% of MSM and 37% of TG were "very likely" to use PrEP. Among MSM, factors associated with PrEP acceptability included a prior history of STIs (AOR 4.6; 95%CIs 1.7-12.6), previous HIV testing (AOR 2.4 95%CIs 1.1-5.3), regularly planned sex (AOR 2.8 95%CIs 1.1-7.2), and infrequent sex (AOR 2.9 95%CIs 1.3-6.3). Among TG, factors associated with acceptability included prior awareness of PrEP (AOR 3.3; 95%CIs 1.2-9.0) and having private insurance (AOR 5.0; 95%CIs 1.3-19.0).

Conclusion

MSM and TG in Northern Thailand are distinct groups in terms of sexual behaviors, patterns of medication use, and correlates of PrEP acceptability. Efforts to maximize PrEP uptake should include expanded HIV testing services and the provision of financial subsidies to reduce the cost of PrEP.

HIV among injection drug users and their intimate partners in Almaty, Kazakhstan

This paper examines prevalence rates of HIV, HCV, and syphilis among a sample of injecting drug users (IDUs) and their heterosexual intimate partners (N = 728) from Almaty, Kazakhstan. The study uses baseline data from Project Renaissance, a couple-based HIV prevention intervention delivered to a couple where one or both partners are IDUs. HIV prevalence rates among female and male IDUs were 28 %. Among the full sample, 75 % had HCV, and 13 % tested positive for the syphilis antibody test. Only 10 % of the sample ever visited a needle exchange program. One-fourth (25.3 %) had never been tested for HIV. One-quarter of those who tested positive were unaware of their status. Being HIV positive was associated with a history of incarceration, being an IDU, and having access to needle exchange programs. The findings call for increasing efforts to improve access to HIV testing, prevention, treatment, and care for IDUs in Almaty, Kazakhstan.

Estimating the impact of reducing violence against female sex workers on HIV epidemics in Kenya and Ukraine: a policy modeling exercise

PROBLEM

Female sex workers (FSWs) worldwide suffer disproportionate burdens of HIV and gender-based violence. Despite evidence linking these threats, little is known about the potential HIV epidemic impact of reducing abuse.

METHOD OF STUDY

The Goals model approximated the impact of reducing violence against FSWs on HIV epidemics in Ukraine and Kenya, measured by reductions in new infections among FSWs and adults. Cumulative infections averted over a 5-year period, in which violence declined was calculated, relative to a status quo with no reduction. Projections held HIV interventions constant at baseline levels; subsequently, scenarios adjusted for planned expansion of antiretroviral therapy (ART) coverage.

RESULTS

An approximate 25% reduction in incident HIV infections among FSWs was observed when physical or sexual violence was reduced; cumulative infections averted were 21,200 and 4700 in Kenya and Ukraine, respectively. Similar percent reductions were observed assuming ART coverage expansion, with approximately 18,200 and 4400 infections averted among FSWs in Kenya and Ukraine. New infections were also averted in the general population.

CONCLUSION

Reducing violence against FSWs appears to impart significant reductions in new infections among FSWs and in the general adult population in both generalized and concentrated epidemics. Limitations provide direction to improve the precision of future estimates.

Social and structural risks for HIV among migrant and immigrant men who have sex with men in Moscow, Russia: implications for prevention

Moscow has a large population of immigrants and migrants from across the Former Soviet Union. Little is studied about men who have sex with men (MSM) within these groups. Qualitative research methods were used to explore identities, practices, and factors affecting HIV prevention and risks among immigrant/migrant MSM in Moscow. Nine interviews and three focus group discussions were conducted between April-June 2010 with immigrant/migrant MSM, analyzed as a subset of a larger population of MSM who participated in qualitative research (n=121). Participants were purposively selected men who reported same sex practices (last 12 months). Migrants were men residing in Moscow but from other Russian regions and immigrants from countries outside of Russia. A socioecological framework was used to describe distal to proximal factors that influenced risks for HIV acquisition. MSM ranged from heterosexual to gay-identified. Stigma and violence related to homophobia in homelands and concerns about xenophobia and distrust of migrants in Moscow were emerged as key themes. Participants reported greater sexual freedom in Moscow but feared relatives in homelands would learn of behaviors in Moscow, often avoiding members of their own ethnicity in Moscow. Internalized homophobia was prevalent and linked to traditional sexual views. Sexual risks included sex work, high numbers of partners, and inconsistent condom use. Avoidance of HIV testing or purchasing false results was related to reporting requirements in Russia, which may bar entry or expel those testing positive. HIV prevention for MSM should consider immigrant/migrant populations, the range of sexual identities, and risk factors among these men. The willingness of some men to socialize with immigrants/migrants of other countries may provide opportunities for peer-based prevention approaches. Immigrants/migrants comprised important proportions of the MSM population, yet are rarely acknowledged in research. Understanding their risks and how to reach them may improve the overall impact of prevention for MSM and adults in Russia.

LGBT Africa: a social justice movement emerges in the era of HIV

LGBT communities are emerging across Africa in 2012. Many are emerging in the context of the continents severe HIV epidemic. Homophobia is a barrier to social acceptance and to health and other social services, but African communities are showing reliance in addressing stigma and discrimination, and in organizing for rights and social tolerance.

Modified social ecological model: a tool to guide the assessment of the risks and risk contexts of HIV epidemics

Background

Social and structural factors are now well accepted as determinants of HIV vulnerabilities. These factors are representative of social, economic, organizational and political inequities. Associated with an improved understanding of multiple levels of HIV risk has been the recognition of the need to implement multi-level HIV prevention strategies. Prevention sciences research and programming aiming to decrease HIV incidence requires epidemiologic studies to collect data on multiple levels of risk to inform combination HIV prevention packages.

Discussion

Proximal individual-level risks, such as sharing injection devices and unprotected penile-vaginal or penile-anal sex, are necessary in mediating HIV acquisition and transmission. However, higher order social and structural-level risks can facilitate or reduce HIV transmission on population levels. Data characterizing these risks is often far more actionable than characterizing individual-level risks. We propose a modified social ecological model (MSEM) to help visualize multi-level domains of HIV infection risks and guide the development of epidemiologic HIV studies. Such a model may inform research in epidemiology and prevention sciences, particularly for key populations including men who have sex with men (MSM), people who inject drugs (PID), and sex workers. The MSEM builds on existing frameworks by examining multi-level risk contexts for HIV infection and situating individual HIV infection risks within wider network, community, and public policy contexts as well as epidemic stage. The utility of the MSEM is demonstrated with case studies of HIV risk among PID and MSM.

Summary

The MSEM is a flexible model for guiding epidemiologic studies among key populations at risk for HIV in diverse sociocultural contexts. Successful HIV prevention strategies for key populations require effective integration of evidence-based biomedical, behavioral, and structural interventions. While the focus of epidemiologic studies has traditionally been on describing individual-level risk factors, the future necessitates comprehensive epidemiologic data characterizing multiple levels of HIV risk.

Modelling the impact of HIV prevention and treatment for men who have sex with men on HIV epidemic trajectories in low- and middle-income countries

Little is known about the impact of combination HIV prevention interventions for men who have sex with men (MSM) and the impacts on the wider epidemics. Modelling analyses of MSM-specific interventions across varied HIV epidemics may inform evidence-based responses. The Goals model was adapted to project the impacts of providing HIV interventions for MSM and access to expanded coverage of antiretroviral therapy (ART) for adults to measure the effects on the MSM and adult epidemics in Peru, Ukraine, Kenya and Thailand. Positive impacts were observed in all four countries. Across epidemics, 14-25% of infections among MSM may be averted between 2012 and 2016 when MSM interventions are brought to scale and MSM have equal access to expanded ART for adults. Among adults, MSM interventions may avert up to 4000 new infections, in addition to the benefits associated with increased ART. Greatest impacts from expanded interventions were observed in countries where same sex transmission contributes significantly to the HIV epidemic. While significant benefits are observed among the adult and MSM populations with expansion of ART, consideration should be given to the synergies of combining ART expansion with targeted interventions to reach hidden, high-risk populations for HIV testing and counselling and linkages to care.

Assessing priorities for combination HIV prevention research for men who have sex with men (MSM) in Africa

A consultation was hosted in South Africa (March 2011) to assess the combination HIV prevention research priorities of academics, implementers and MSM community leaders. Sixty-nine participants, representing 17 African countries, participated. Interactive strategies were used to present current data on HIV interventions and discussions on research possibilities were facilitated with research priorities identified using the nominal group technique. Data were analysed using directed content analysis. Health worker training, social mobilisation, and community engagement were prioritised as structural interventions. Comprehensive counselling was identified as the most important behavioural intervention, with adherence, mental health, and risk reduction counselling identified as key counselling topics. Rectal microbicides, oral pre-exposure prophylaxis and condom and lubricant distribution were the most important biomedical interventions. This consultation resulted in the first combination HIV prevention research agenda for MSM in Africa. Outcomes will inform future research and be used to advocate for combination approaches to HIV prevention for MSM.

Examining the evidence on the causal effect of HAART on transmission of HIV using the Bradford Hill criteria

In recent years, evidence has accumulated regarding the ability of HAART to prevent HIV transmission. Early supportive evidence was derived from observational, ecological and population-based studies. More recently, a randomized clinical trial showed that immediate use of HAART led to a 96% decrease in HIV transmission events within HIV serodiscordant heterosexual couples. However, the generalizability of the effect of HAART, and the population-level impact on HIV transmission continues to generate substantial debate. We, therefore, conducted a review of the evidence regarding the preventive effect of HAART on HIV transmission within the context of the Bradford Hill criteria for causality. Taken together, we find the accumulated evidence supporting HIV treatment as prevention meets each of the Bradford Hill criteria for causality. We conclude that the opportunity cost of inaction while waiting for additional evidence on the generalizability of effect in other risk groups is too high. Efforts should be redoubled to mobilize the financial capital and political will to optimize implementation of HIV Treatment as Prevention strategies on a wide scale.