Willingness-to-accept reductions in HIV risks: conditional economic incentives in Mexico

Incentive-Based Human Immunodeficiency Virus Screening in Low- and Middle-Income Countries: A Systematic Review

BACKGROUND

The majority of new human immunodeficiency virus (HIV) infections that occur worldwide are in sub-Saharan Africa. While recent gains have been made in many low- and middle-income countries (LMICs), substantial disparities in sexually transmitted and blood-borne infections (STBBI) screening and treatment still exist between LMIC and high-income countries. In addition to increasing STBBI screening uptake, providing incentives for STBBI screening may decrease perceived stigma associated with STBBI screening.

METHODS

Our review was conducted as part of a larger systematic review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement and guidance from the Cochrane Handbook for Systematic Reviews of Interventions. This review focuses on incentivized STBBI screening in LMIC; high-income countries were excluded. Articles were excluded if their primary focus was on children and youth (younger than 16 years), results retrieval, treatment, behavioral change only, behavior intention, treatment adherence, or provider incentive.

RESULTS

The search yielded 6219 abstracts. The search and selection criteria included all STBBI; however, only articles examining incentivized HIV screening met our inclusion criteria. Five articles representing 4 distinct studies from South Africa, Uganda, and Zimbabwe were included, all of which focused on incentivized HIV screening. Populations screened included the following: men, first-time testers, population-based surveillance program families, and insurance health plan members. Incentive structures varied widely and incentives were mainly food vouchers, lottery prizes, or household items.

CONCLUSIONS

Our review was conducted to determine if patient incentives increase STBBI test uptake in LMIC. Overall, incentives were associated with an increase in HIV screening uptake. Most studies included focused solely on men. There is a significant void in understanding STBBI incentive-based screening outside of this context and in complex populations who should be targeted in incentivized HIV screening. Incentives appear most effective when developed specific to context and target population. Further research is needed to analyze incentivized screening across similar study designs, to evaluate long-term effectiveness, and to explore the ethical implications of incentivized care.

Preferences for Conditional Economic Incentives to Improve Pre-exposure Prophylaxis Adherence: A Discrete Choice Experiment Among Male Sex Workers in Mexico

Pre-exposure prophylaxis (PrEP) is highly effective in preventing HIV but requires sustained adherence. Conditional economic incentives (CEIs) can improve medication-taking behaviors, yet preferences for programs that employ CEIs to increase PrEP use among male sex workers (MSWs) have not been investigated. We conducted a discrete choice experiment in Mexico City to elicit stated preferences for a CEI-based PrEP adherence program among MSWs. Respondents expressed their preferences for different program characteristics: incentive amount; incentive format; incentive type; and adherence-verification method. We used a random utility logit model to estimate the relative importance of each attribute and estimated willingness-to-pay. MSWs preferred a higher, fixed incentive, with PrEP adherence measured via hair sampling. MSWs were willing to forego up to 21% of their potential maximum CEI amount to ensure receipt of a fixed payment. MSWs are highly willing to accept a CEI-based intervention for PrEP adherence, if offered along with fixed payments.

Incorporating respondent-driven sampling into web-based discrete choice experiments: preferences for COVID-19 mitigation measures

To slow the spread of COVID-19, most countries implemented stay-at-home orders, social distancing, and other nonpharmaceutical mitigation strategies. To understand individual preferences for mitigation strategies, we piloted a web-based Respondent Driven Sampling (RDS) approach to recruit participants from four universities in three countries to complete a computer-based Discrete Choice Experiment (DCE). Use of these methods, in combination, can serve to increase the external validity of a study by enabling recruitment of populations underrepresented in sampling frames, thus allowing preference results to be more generalizable to targeted subpopulations. A total of 99 students or staff members were invited to complete the survey, of which 72% started the survey (n = 71). Sixty-three participants (89% of starters) completed all tasks in the DCE. A rank-ordered mixed logit model was used to estimate preferences for COVID-19 nonpharmaceutical mitigation strategies. The model estimates indicated that participants preferred mitigation strategies that resulted in lower COVID-19 risk (i.e. sheltering-in-place more days a week), financial compensation from the government, fewer health (mental and physical) problems, and fewer financial problems. The high response rate and survey engagement provide proof of concept that RDS and DCE can be implemented as web-based applications, with the potential for scale up to produce nationally-representative preference estimates.

Barriers and facilitators to pre-exposure prophylaxis uptake among male sex workers in Mexico: an application of the RE-AIM framework

Background

The ImPrEP México demonstration project is the first to distribute free HIV pre-exposure prophylaxis (PrEP) to men who have sex with men (MSM) and transgender women living in Mexico. In Mexico City, MSM who are also male sex workers (MSWs) face a disproportionately high risk of HIV infection. PrEP is highly effective for HIV prevention, yet “real-life” implementation among MSWs is a challenge due to the unique adherence barriers faced by this population.

Methods

This study uses the RE-AIM implementation science framework to characterize the unique barriers to and facilitators of PrEP uptake among MSWs in Mexico City. We conducted 9 in-depth key informant interviews and 2 focus group discussions with MSWs across 5 clinic and community sites. Qualitative data were analyzed using inductive, open coding approaches from grounded theory. We supplemented findings from the primary qualitative analysis with quantitative indicators derived from ImPrEP program records to describe the current Reach of the ImPrEP program among MSWs in Mexico City and the potential for wider PrEP Adoption among other high-risk populations in Mexico.

Results

The Reach of the ImPrEP program was 10% of known HIV-negative MSWs in Mexico City. Program Reach was lowest among MSWs who were street-based sex workers, of lower socioeconomic status, migrants from other states and self-identified as heterosexual. Barriers to program Reach included limited PrEP knowledge, HIV-related stigma, and structural barriers; facilitators included in-person program recruitment, patient-centered care, and spread of information through word of mouth among MSWs. Two out of the four eligible institutions had adopted the ImPrEP protocol. Barriers to wider program Adoption included HIV- and sexual identity– related stigma, protocol limitations, and lack of a national policy for PrEP distribution; facilitators of Adoption included existing healthcare infrastructure, sensitized providers, and community support from non-governmental organizations.

Conclusions

Increasing the ImPrEP program’s Reach among MSWs will depend on improving PrEP education and addressing HIV-related stigma and access barriers. Future Adoption of the ImPrEP program should build on existing clinical infrastructure and community support. Creation of a national policy for PrEP distribution may improve the Reach and Adoption of PrEP among highest-risk populations in Mexico.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-12167-9.

Patient Perspectives and Willingness to Accept Incentives for Tuberculosis Diagnostic Evaluation in Uganda

OBJECTIVES

We assessed attitudes and perceptions and willingness to accept (WTA) varying incentive structures for completing tuberculosis (TB) diagnostic evaluation among patients in Uganda.

METHODS

We surveyed 177 adult patients undergoing TB evaluation at 10 health centers between September 2018 and March 2019. We collected household sociodemographic information and assessed attitudes and perceptions of incentives. We surveyed patients regarding their willingness to complete TB diagnostic evaluation in exchange for incentives ranging in value from 500 Ugandan shillings (USh) to 25 000USh (~$0.15-$6.75). We compared associations between WTA and patient characteristics using ordered logistic regression.

RESULTS

Participant willingness to return to the health center to complete TB diagnostic evaluation increased proportionally with incentive amount. The median participant accepted between 2000 and 5000 USh. Cash (52%) and transportation vouchers (34%) were the most popular incentive types. Half of respondents preferred unconditional incentives; for a multiday evaluation, 84% preferred conditioning incentive receipt upon returning to the health center. In multivariate models, we found the pairwise difference between the third and lowest income quartile (aOR = 2.38, 95% CI: 1.20-4.69; P = .01), younger age, and difficulty returning to the health center to be significantly associated with WTA higher incentive thresholds.

CONCLUSIONS

In Uganda, incentives such as cash transfers or transportation vouchers are an acceptable intervention for facilitating adherence to TB diagnostic evaluation. Household income is associated with preferred incentive structure and amount, especially for those at the cusp of the poverty threshold who are more likely to prefer unconditional and higher valued incentives. Targeted and context-specific socioeconomic supports for at-risk patients are needed to optimize outcomes.

Incidence and time-varying predictors of HIV and sexually transmitted infections among male sex workers in Mexico City

Background

Male sex workers are at high-risk for acquisition of sexually transmitted infections (STIs), including human immunodeficiency virus (HIV). We quantified incidence rates of STIs and identified their time-varying predictors among male sex workers in Mexico City.

Methods

From January 2012 to May 2014, male sex workers recruited from the largest HIV clinic and community sites in Mexico City were tested for chlamydia, gonorrhea, syphilis, hepatitis, and HIV at baseline, 6-months, and 12-months. Incidence rates with 95% bootstrapped confidence limits were calculated. We examined potential time-varying predictors using generalized estimating equations for a population averaged model.

Results

Among 227 male sex workers, median age was 24 and baseline HIV prevalence was 32%. Incidence rates (per 100 person-years) were as follows: HIV [5.23; 95% confidence interval (CI): 2.15–10.31], chlamydia (5.15; 95% CI: 2.58–9.34), gonorrhea (3.93; 95% CI: 1.88–7.83), syphilis (13.04; 95% CI: 8.24–19.94), hepatitis B (2.11; 95% CI: 0.53–4.89), hepatitis C (0.95; 95% CI: 0.00–3.16), any STI except HIV (30.99; 95% CI: 21.73–40.26), and any STI including HIV (50.08; 95% CI: 37.60–62.55). In the multivariable-adjusted model, incident STI (excluding HIV) were lower among those who reported consistently using condoms during anal and vaginal intercourse (odds ratio = 0.03, 95% CI: 0.00–0.68) compared to those who reported inconsistently using condoms during anal and vaginal intercourse.

Conclusions

Incidence of STIs is high among male sex workers in Mexico City. Consistent condom use is an important protective factor for STIs, and should be an important component of interventions to prevent incident infections.

Conditional economic incentives to improve HIV prevention and treatment in low-income and middle-income countries

New and innovative approaches are needed to improve the prevention, diagnosis, and treatment of HIV in low-income and middle-income countries. Several trials use conditional economic incentives (CEIs) to improve HIV outcomes. Most CEI interventions use a traditional economic theory approach, although some interventions incorporate behavioural economics, which combines traditional economics with insights from psychology. Incentive interventions that are appropriately implemented can increase HIV testing rates and voluntary male circumcision, and they can improve other HIV prevention and treatment outcomes in certain settings in the short term. More research is needed to uncover theory-based mechanisms that increase the duration of incentive effects and provide strategies for susceptible individuals, which will help to address common constraints and biases that can influence health-related decisions.

The Relationship Between Psychological Temporal Perspective and HIV/STI Risk Behaviors Among Male Sex Workers in Mexico City

Men who have sex with men (MSM) face a disproportionate burden of HIV incidence and HIV prevalence, particularly young men who have sex with men. The aim of this article was to analyze the relation between a psychological temporal perspective and HIV/sexually transmitted infection (STI) risk behaviors among male sex workers (MSWs), a potentially highly present-oriented group of MSM. A total sample of 326 MSWs were included and responded to a validated psychological scale: the Zimbardo's Time Perspective Inventory; they also reported how frequently they engaged in protective behaviors against HIV and other STI risks behaviors, including condom use with casual and regular partners, as well as prior HIV testing. We adjusted structural equation models to analyze the relation between a psychological temporal perspective and HIV/STI risk behaviors. We found that orientation toward the past was correlated with decreased condom use with casual partners (β = - 0.18; CI_95% - 0.23, - 0.12). Future orientation was not associated with condom use with casual partners. Regarding condom use with regular partners, past and present orientation were related to lower likelihood of condom use (β = - 0.23; CI_95% - 0.29, - 0.17; β = - 0.11; CI_95% - 0.19, - 0.02), whereas future orientation increased the likelihood of condom use with regular partners (β = 0.40; CI_95% 0.31, 0.50). Time orientation (past, present, or future) did not predict the probability of having an HIV test. The design of HIV/STI prevention programs among vulnerable populations, such as MSM and MSWs, should consider specific time-frame mechanisms that can importantly affect sexual risk behavior decisions.

Punto Seguro: A Randomized Controlled Pilot Using Conditional Economic Incentives to Reduce Sexually Transmitted Infection Risks in Mexico

Randomized controlled pilot evaluated effect of conditional economic incentives (CEIs) on number of sex partners, condom use, and incident sexually transmitted infections (STIs) among male sex workers in Mexico City. Incentives were contingent on testing free of new curable STIs and/or clinic attendance. We assessed outcomes for n = 227 participants at 6 and 12 months (during active phase with incentives), and then at 18 months (with incentives removed). We used intention-to-treat and inverse probability weighting for the analysis. During active phase, CEIs increased clinic visits (10-13 percentage points) and increased condom use (10-15 percentage points) for CEI groups relative to controls. The effect on condom use was not sustained once CEIs were removed. CEIs did not have an effect on number of partners or incident STIs. Conditional incentives for male sex workers can increase linkage to care and retention and reduce some HIV/STI risks such as condomless sex, while incentives are in place.

The impact of behavioural risk reduction interventions on willingness to pay to avoid sexually transmitted infections: a stated preference study of justice-involved youth

Risky health behaviours, such as smoking, drinking and risky sex, are substantial contributors to US morbidity rates and healthcare costs. While economic models typically regard preferences as stable, a growing literature suggests that information, including how it interacts with intentions and attitudes, plays an important role in unhealthy behaviours. Relatedly, a large health literature demonstrates that theory-based behavioural interventions can successfully change risky behaviour. This study uses the contingent valuation survey method to investigate the impact of behavioural interventions on a novel outcome measure: the willingness to pay (WTP) to avoid the consequences associated with risky behaviour. Using novel pre- and post-intervention data from Project MARS (Motivating Adolescents to Reduce Sexual Risk) this study estimates the impact of the intervention on elicited WTP to avoid sexually transmitted infections (STI). It is found that after the intervention, participants' elicited WTP to avoid STIs were significantly higher, and more sensitive to differences in infection severity. These results suggest that the intervention may affect risky sexual behaviour by changing the perceived value of avoiding the consequences of risky sexual behaviour. Additionally, these findings contribute to an ongoing debate regarding the construct validity of contingent valuation studies in health economics.

Female sex workers use power over their day-to-day lives to meet the condition of a conditional cash transfer intervention to incentivize safe sex

Female Sex Workers are a core population in the HIV epidemic, and interventions such as conditional cash transfers (CCTs), effective in other health domains, are a promising new approach to reduce the spread of HIV. Here we investigate how a population of Tanzanian female sex workers, though constrained in many ways, experience and use their power in the context of a CCT intervention that incentivizes safe sex. We analyzed 20 qualitative in-depth interviews with female sex workers enrolled in a randomized-controlled CCT program, the RESPECT II pilot, and found that while such women have limited choices, they do have substantial power over their work logistics that they leveraged to meet the conditions of the CCT and receive the cash award. It was through these decisions over work logistics, such as reducing the number of workdays and clients, that the CCT intervention had its greatest impact on modifying female sex workers' behavior.

Which strings attached: ethical considerations for selecting appropriate conditionalities in conditional cash transfer programmes

Conditional cash transfers (CCTs) present a promising approach to simultaneously tackle chronic poverty and poor health. While these programmes clearly embody beneficent aims, questions remain regarding the ethical design of CCTs. Limited guidance exists for the ethical evaluation of the defining feature of these programmes: the conditionalities. Drawing upon prominent public health ethics frameworks and social justice theories, this paper outlines five categories of morally relevant considerations that CCT programme designers should consider when assessing which behaviours or outcomes they select as conditionalities for payment: (1) likelihood of yielding desired health outcomes, (2) risks and burdens, (3) receptivity, (4) attainability and (5) indirect impacts and externalities. When evaluating potential conditionalities across these five categories of considerations, it is important to recognise that not all beneficiaries or subgroups of beneficiaries will fare equally on each. Given that most CCTs aim to reduce inequities and promote long-term health and prosperity for the most disadvantaged, it is critical to apply these considerations with due attention to how different segments of the beneficiary population will be differentially affected. Taken on balance, with due reflection on distributional effects, these five categories represent a comprehensive set of considerations for the moral analysis of specific conditionalities and will help ensure that CCT designers structure programmes in a way that is both morally sound and effective in achieving their goals.

How to sell a condom? The impact of demand creation tools on male and female condom sales in resource limited settings

Despite condoms being cheap and effective in preventing HIV, there remains an 8billion shortfall in condom use in risky sex-acts. Social marketing organisations apply private sector marketing approaches to sell public health products. This paper investigates the impact of marketing tools, including promotion and pricing, on demand for male and female condoms in 52 countries between 1997 and 2009. A static model differentiates drivers of demand between products, while a dynamic panel data estimator estimates their short- and long-run impacts. Products are not equally affected: female condoms are not affected by advertising, but highly affected by interpersonal communication and HIV prevalence. Price and promotion have significant short- and long-run effects, with female condoms far more sensitive to price than male condoms. The design of optimal distribution strategies for new and existing HIV prevention technologies must consider both product and target population characteristics.

Would you test for 5000 Shillings? HIV risk and willingness to accept HIV testing in Tanzania

OBJECTIVES

Despite substantial public health efforts to increase HIV testing, testing rates have plateaued in many countries and rates of repeat testing for those with ongoing risk are low. To inform policies aimed at increasing uptake of HIV testing, we identified characteristics associated with individuals' willingness-to-accept (WTA) an HIV test in a general population sample and among two high-risk populations in Moshi, Tanzania.

METHODS

In total, 721 individuals, including randomly selected community members (N = 402), female barworkers (N = 135), and male Kilimanjaro mountain porters (N = 184), were asked in a double-bounded contingent valuation format if they would test for HIV in exchange for 2000, 5000 or 10,000 Shillings (approximately $1.30, $3.20, and $6.40, respectively). The study was conducted between September 2012 and February 2013.

RESULTS

More than one quarter of participants (196; 27 %) stated they would be willing to test for Tanzania Shilling (TSH) 2000, whereas one in seven (98; 13.6 %) required more than TSH 10,000. The average WTA estimate was TSH 4564 (95 % Confidence Interval: TSH 4201 to 4927). Significant variation in WTA estimates by gender, HIV risk factors and other characteristics plausibly reflects variation in individuals' valuations of benefits of and barriers to testing. WTA estimates were higher among males than females. Among males, WTA was nearly one-third lower for those who reported symptoms of HIV than those who did not. Among females, WTA estimates varied with respondents' education, own and partners' HIV testing history, and lifetime reports of transactional sex. For both genders, the most significant association was observed with respondents' perception of the accuracy of the HIV test; those believing HIV tests to be completely accurate were willing to test for approximately one third less than their counterparts. The mean WTA estimates identified in this study suggest that within the study population, incentivized universal HIV testing could potentially identify undiagnosed HIV infections at an incentive cost of $150 per prevalent infection and $1400 per incident infection, with corresponding costs per quality adjusted life year (QALY) gained of $70 for prevalent and $620 for incident HIV infections.

CONCLUSIONS

The results support the value of information about the accuracy of HIV testing, and suggest that relatively modest amounts of money may be sufficient to incentivize at-risk populations to test.

Preventing HIV Transmission Among Partners of HIV-Positive Male Sex Workers in Mexico City: A Modeling Study

Mexico has a concentrated HIV epidemic, with male sex workers constituting a key affected population. We estimated annual HIV cumulative incidence among male sex workers' partners, and then compared incidence under three hypothetical intervention scenarios: improving condom use; and scaling up HIV treatment as prevention, considering current viral suppression rates (CVS, 60.7 %) or full viral suppression among those treated (FVS, 100 %). Clinical and behavioral data to inform model parameterization were derived from a sample (n = 79) of male sex workers recruited from street locations and Clínica Condesa, an HIV clinic in Mexico City. We estimated annual HIV incidence among male sex workers' partners to be 8.0 % (95 % CI: 7.3-8.7). Simulation models demonstrated that increasing condom use by 10 %, and scaling up HIV treatment initiation by 50 % (from baseline values) would decrease the male sex workers-attributable annual incidence to 5.2, 4.4 % (CVS) and 3.2 % (FVS), respectively. Scaling up the number of male sex workers on ART and implementing interventions to ensure adherence is urgently required to decrease HIV incidence among male sex workers' partners in Mexico City.

Combination HIV prevention for female sex workers: what is the evidence?

Sex work occurs in many forms and sex workers of all genders have been affected by HIV epidemics worldwide. The determinants of HIV risk associated with sex work occur at several levels, including individual biological and behavioural, dyadic and network, and community and social environmental levels. Evidence indicates that effective HIV prevention packages for sex workers should include combinations of biomedical, behavioural, and structural interventions tailored to local contexts, and be led and implemented by sex worker communities. A model simulation based on the South African heterosexual epidemic suggests that condom promotion and distribution programmes in South Africa have already reduced HIV incidence in sex workers and their clients by more than 70%. Under optimistic model assumptions, oral pre-exposure prophylaxis together with test and treat programmes could further reduce HIV incidence in South African sex workers and their clients by up to 40% over a 10-year period. Combining these biomedical approaches with a prevention package, including behavioural and structural components as part of a community-driven approach, will help to reduce HIV infection in sex workers in different settings worldwide.

The disproportionate burden of HIV and STIs among male sex workers in Mexico City and the rationale for economic incentives to reduce risks

Introduction

The objective of this article is to present the rationale and baseline results for a randomized controlled pilot trial using economic incentives to reduce HIV and sexually transmitted infection (STI) risk among male sex workers (MSWs) in Mexico City.

Methods

Participants (n=267) were tested and treated for STIs (chlamydia, gonorrhoea, syphilis and HIV) and viral hepatitis (hepatitis B and C), received HIV and STI prevention education and were randomized into four groups: (1) control, (2) medium conditional incentive ($50/six months), (3) high conditional incentive ($75/six months) and (4) unconditional incentive ($50/six months). In the conditional arms, incentives were contingent upon testing free of new curable STIs (chlamydia, gonorrhoea and syphilis) at follow-up assessments.

Results

Participants’ mean age was 25 years; 8% were homeless or lived in a shelter, 16% were unemployed and 21% lived in Mexico City less than 5 years. At baseline, 38% were living with HIV, and 32% tested positive for viral hepatitis or at least one STI (other than HIV). Participants had a mean of five male clients in the previous week; 18% reported condomless sex with their last client. For 37%, sex work was their main occupation and was conducted mainly on the streets (51%) or in bars/discotheques (24%) and hotels (24%). The average price for a sex transaction was $25 with a 35% higher payment for condomless sex.

Conclusions

The findings suggest that economic incentives are a relevant approach for HIV prevention among MSWs, given the market-based inducements for unprotected sex. This type of targeted intervention seems to be justified and should continue to be explored in the context of combination prevention efforts.

Yo Puedo--a conditional cash transfer and life skills intervention to promote adolescent sexual health: results of a randomized feasibility study in san francisco

PURPOSE

We designed and evaluated for feasibility an intervention-Yo Puedo-that addresses social network influences and socioeconomic opportunities in a neighborhood with substantial gang exposure and early childbearing.

METHODS

Yo Puedo combined conditional cash transfers for completion of educational and reproductive health wellness goals with life skills sessions, and targeted youth 16-21 years of age and same-aged members of their social network. We conducted a two-arm study with social networks randomized to the intervention or a standard services control arm. We evaluated intervention uptake, adherence, and safety; and assessed evidence of effects on behavioral outcomes associated with unintended pregnancy and sexually transmitted infection risk.

RESULTS

A total of 72 social networks composed of 162 youth enrolled, with 92% retention over 6 months. Seventy-two percent of youth randomized to the intervention participated in intervention activities: 53% received at least one conditional cash transfer payment and 66% came to at least one life skills session. We found no evidence that cash payments financed illicit or high-risk behavior. At 6 months, compared with controls, intervention participants had a lower odds of hanging out on the street frequently (odds ratio [OR], .54; p = .10) and a lower odds of reporting that their close friends had been incarcerated (OR, .6; p = .12). They reported less regular alcohol use (OR, .54; p = .04) and a lower odds of having sex (OR, .50; p = .04).

CONCLUSIONS

The feasibility evaluation of Yo Puedo demonstrated its promise; a larger evaluation of effects on pregnancy and sustained behavioral changes is warranted.

Is the HIV epidemic stable among MSM in Mexico? HIV prevalence and risk behavior results from a nationally representative survey among men who have sex with men

BACKGROUND

Recent evidence points to the apparent increase of HIV prevalence among men who have sex with men (MSM) in different settings with concentrated epidemics, including the Latin American region. In 2011, Mexico implemented an ambitious HIV prevention program in all major cities, funded by the Global Fund to Fight Aids, Tuberculosis and Malaria. The program was intended to strengthen the prevention response for the most at risk populations: MSM and injecting drug users. This paper presents the HIV prevalence results of a nationally representative baseline survey in 24 Mexican cities throughout the 5 regions in the country and reports the socio-demographic and sexual risk behaviors that predict the probability of infection.

METHODS

The survey was implemented in two phases. We first identified and characterized places where MSM gather in each city and then conducted in a second phase, a seroprevalence survey that included rapid HIV testing and a self-administered questionnaire. The prevalence of HIV was estimated by adjusting for positive predicted value. We applied a probit model to estimate the probability of having a positive result from the HIV test as a function of socio-demographic characteristics and self-reported sexual risk behaviors.

RESULTS

We found an overall HIV prevalence among MSM gathering in meeting points of 16.9% [95% CI: 15.6-18.3], significantly higher than previously reported estimates. Our regression results suggest that the risk of infection increases with age, with the number of sexual partners, and among those who play a receptive sexual role, and the risk decreases with higher education.

DISCUSSION

Our findings suggest a higher HIV prevalence among MSM than previously acknowledged and that a significant regional variability exist throughout the country. These two findings combined, signal an important dynamic in the epidemic that should be better understood and promptly addressed with strong prevention efforts targeted at key populations.