Wipas Wimonsate

Trends in HIV Prevalence, Estimated HIV Incidence, and Risk Behavior Among Men Who Have Sex With Men in Bangkok, Thailand, 2003–2007.

Background:Men who have sex with men (MSM) continue to be at high risk for HIV infection. Here we evaluate trends in HIV prevalence, estimated HIV incidence, and risk behavior among MSM in Bangkok, Thailand. Methods:Between 2003 and 2007, 3 biennial cross-sectional HIV prevalence assessments were conducted among MSM in Bangkok, Thailand, using venue-day-time sampling. Oral fluid was tested for HIV infection; demographic and behavioral data were self-collected using hand-held computers. Estimates of annual HIV incidence in young MSM were derived as follows: (number of HIV infections/sum of [current age-age at start of anal intercourse]) × 100). Logistic and Poisson regression was used to evaluate trends in HIV prevalence, estimated HIV incidence, and risk behavior. Findings:The overall HIV prevalence increased from 17.3% in 2003 to 28.3% in 2005 to 30.8% in 2007 (P < 0.001 for trend). The estimated HIV incidence among young MSM increased from 4.1% in 2003 to 6.4% in 2005, to 7.7% in 2007 (P < 0.02 for trend). The increase in HIV prevalence from 2005 to 2007 was not statistically significant. The proportion of men reporting anal sex and casual or steady male sex partners in the past 3 months significantly decreased, whereas the proportion reporting drug use and drug use during sex significantly increased. No increase was observed in the proportion of men reporting consistent condom use. Interpretation:Our data suggest that after a strong increase from 2003 to 2005, the HIV prevalence among MSM in Bangkok may have begun to stabilize. Given the continuing high levels of risk behavior and the estimated high HIV incidence in young MSM, additional HIV preventive interventions are necessary.

HIV Prevalence, Risk Behavior, Hormone Use and Surgical History Among Transgender Persons in Thailand

While Male-to-female transgender persons (TG) are believed to often engage in sex work and have high HIV infection risk, little is known about demographics, surgical and hormone use history, risk behaviors and HIV prevalence. Between March and October 2005, 474 TG from Bangkok, Chiangmai, and Phuket were surveyed using venue-day-time sampling. Of 474 participants, overall HIV prevalence was 13.5%. Most participants had completed at least secondary or vocational education (79.2%), gender self-identified as female (89.0%), had received money, gifts or valuables for sex (60.8%), and reported hormone use (88.6%). Surgical history was taken from 325 participants. Of these, 68.6% reported some form of surgery and 11.1% had undergone penile-vaginal reconstructive surgery. In multivariate analysis, being recruited from a park/street; older age, anal sex role identification as “versatile” and anal sex debut before age 13 were independently associated with HIV prevalence. The development, implementation and evaluation of culturally appropriate sexual health interventions for Thai TG is urgently needed.

Sex frequency and sex planning among men who have sex with men in Bangkok, Thailand: implications for pre- and post-exposure prophylaxis against HIV infection

BackgroundDaily HIV antiretroviral pre-exposure prophylaxis (PrEP) is being evaluated in clinical trials among men who have sex with men (MSM). However, daily PrEP may not be congruent with sexual exposure profiles of MSM. Here, we investigate sex frequency and sex planning to identify and inform appropriate PrEP strategies for MSM.MethodsWe evaluated sex frequency and sex planning in a cohort of HIV-negative MSM in Bangkok, Thailand. Chi-squared test was used to compare reports of sex on different weekdays; logistic regression was used to identify predictors of sex frequency and sex planning.ResultsOf 823 MSM (with a mean age of 28.3 years), 86% reported having sex on two days per week or less, and 65% reported their last sex to have been planned. Sex on the weekend (~30%) was more often reported than sex on weekdays (~23%). In multivariate analysis, use of alcohol, erectile dysfunction drugs, group sex, sex with a foreigner, buying and selling sex, and a history of HIV testing were associated with having sex on three days or more per week. Being aged 22 to 29 years, not identifying as homosexual, having receptive anal intercourse, and not engaging in group sex were associated with unplanned sex.ConclusionsIntermittently dosed PrEP (as opposed to daily) may be a feasible HIV prevention strategy and should be considered for evaluation in clinical trials. Risk factors for sex frequency and sex planning may help to identify those in need for daily PrEP and those who may not be able to take a timely pre-exposure dose.

Knowledge of and Interest in Using Preexposure Prophylaxis for HIV Prevention among Men Who Have Sex with Men in Thailand

Little is known about HIV preexposure prophylaxis (PrEP) acceptability among men who have sex with men (MSM) in Thailand. The authors recruited an online convenience sample of Thai MSM (n = 404) to assess the knowledge of and interest in PrEP. Less than 7% had heard of PrEP; however, 35% indicated interest in PrEP after an explanation of its possible efficacy. Regression modeling demonstrated that HIV knowledge and risk behavior, but not demographics, are significant predictors of PrEP interest. More information and education about PrEP is necessary and more research is needed to examine PrEP acceptability and to inform the message for PrEP uptake.

Temporal trends in HIV-1 incidence and risk behaviours in men who have sex with men in Bangkok, Thailand, 2006-13: An observational study

BACKGROUND HIV-1 incidence in men who have sex with men (MSM) is often difficult to estimate. We therefore assessed temporal trends in HIV-1 incidence and behavioural risk factors in MSM in Bangkok, Thailand, from 2006 to 2013. METHODS In this observational study, we used data for clients attending the Silom Community Clinic for voluntary counselling and testing (VCT) services and from the Bangkok MSM Cohort Study (BMCS) to investigate trends in HIV incidence per 100 person-years per quarter in both cohorts. During VCT, basic demographic data were gathered at registration. However, no behavioural risk data were gathered. In the BMCS, we gathered demographic and behavioural data at baseline and at regular study visits using audio computer-assisted self-interviewing. Questions were included about potential risk factors such as drug use, sexual practices, and how often condoms were used. We also analysed behavioural risk factors in the BMCS cohort, using a restricted cubic spline function for time. FINDINGS From 2006 to 2013, 8176 MSM came for VCT; 1999 (24%) clients were initially seronegative and returned for another test. 235 (12%) individuals seroconverted. The overall HIV-1 incidence was 5.5 per 100 person-years (95% CI 4.8-6.3), with an increasing trend (adjusted p=0.02). In the BMCS, 1372 people were seronegative at baseline; 1259 (92%) had more than one follow-up test and 238 (17%) seroconverted. The overall HIV-1 incidence was 5.3 per 100 person-years (95% CI 4.7-6.1), with an increase and then a decline (inverted U-shaped curve, p=0.0001). Individuals aged 21 years and younger were at significantly higher risk of HIV infection than were those aged 30 years and older in the in the VCT (rate ratio 2.29, 95% CI 1.88-2.78, p<0.0001) and BMCS cohorts (1.99, 1.50-2.65, p<0.0001). Overall, drug use (p=0.03), drug use to enhance sex (p=0.0006), use of drugs for erectile dysfunction (p<0.0001), and 100% condom use (p<0.0001) increased over time, whereas the proportion of individuals reporting receptive anal intercourse decreased (p=0.004). INTERPRETATION With a sustained high HIV-1 incidence and increasing drug use in MSM in Bangkok, we urgently need innovative and acceptable HIV prevention interventions, especially for young MSM. FUNDING US Centers for Disease Control and Prevention.

Prevalence of Treponema pallidum seropositivity and herpes simplex virus type 2 infection in a cohort of men who have sex with men, Bangkok, Thailand, 2006–2010

We report prevalence of Treponema pallidum (TP) seropositivity and herpes simplex virus type 2 (HSV-2) infection and risk factors associated with their prevalence in a cohort of men who have sex with men (MSM) in Bangkok, Thailand. Between April 2006 and March 2010 we enrolled Thai MSM into a cohort study based at the Silom Community Clinic, with baseline behavioural data and laboratory testing for sexually transmitted infections (STIs). Logistic regression was used to analyse risk factors associated with the prevalence of TP seropositivity and HSV-2 infection. From a total of 1544 enrolled men (mean age 26 years) TP, HSV-2 and HIV seropositive rates were 4.4%, 20.7% and 21.6%, respectively. After multivariable analysis, participating in group sex, reporting paying for sex, reporting sex with a casual partner in a park and being HSV-2 seropositive were associated with TP prevalence. Age ≥30 years, having less than a high school education, past use of recreational drugs, meeting casual sexual partners at a public venue (sauna) and TP seropositivity were associated with HSV-2 infection. The significant baseline prevalence of TP seropositivity and HSV-2 infection in this cohort demonstrates the need for screening and treatment of these STIs and targeted prevention interventions in Thai MSM in Bangkok.

Young Men Who Have Sex with Men at High Risk for HIV, Bangkok MSM Cohort Study, Thailand 2006–2014

High HIV incidence has been reported in young men who have sex with men (YMSM) in North America and Western Europe, but there are limited data from Southeast Asia suggesting MSM may be the driver of the HIV epidemic in this region. We described HIV incidence and risk factors among 494 YMSM enrolled in a cohort study in Bangkok, Thailand. The HIV incidence was 7.4 per 100 person-years. In multivariable analysis, reporting use of an erectile dysfunction drug in combination with club drugs, having receptive or both insertive and receptive anal intercourse with men, having hepatitis A infection, having rectal Chlamydia trachomatis, having hepatitis B infection prior to HIV seroconversion, and reporting not always using condoms with male steady partners were significantly associated with HIV incidence in YMSM. Reduction in new HIV infections in YMSM are critical to reach targets set by Thailand and the region.

Loss to follow-up and bias assessment among a cohort of Thai men who have sex with men in Bangkok, Thailand

Minimising loss to follow-up is essential to obtain unbiased results. This study aimed to assess factors associated with loss to follow-up and effects on biasing exposure-outcome associations in a cohort of men who have sex with men in Bangkok. We enrolled sexually-active Thai men who have sex with men, at least 18 years old, in a study with four-monthly follow-up visits. At each visit, men answered HIV risk behaviour questions using audio computer-assisted self-interview. Logistic regression was used to evaluate factors associated with loss to follow-up and bias between exposures and prevalent HIV infection were estimated using adjusted relative odds ratios. From 2006 to 2010, we enrolled 1744 men who have sex with men; as of April, 2014, 1256 (72%) had completed at least the month-36 visit; loss to follow-up was 9.6%. Factors independently associated with loss to follow-up were age (18–21 years), education (primary level or less, secondary or vocational education), living outside Bangkok and vicinity, sexual orientation (bisexual, heterosexual), previous HIV testing, HIV infection, and behaviour in the past 4 months (recreational drug use, reporting group sex). An effect of loss to follow-up on factors of prevalent HIV infection was found by sexual orientation (transgender) and unprotected anal intercourse (receptive/insertive). These findings highlight the need to strengthen post-HIV test counselling. Directed counselling for HIV care should be given to young men who have sex with men and recreational drug users.

The finding of casual sex partners on the internet, methamphetamine use for sexual pleasure, and incidence of HIV infection among men who have sex with men in Bangkok, Thailand: an observational cohort study

BACKGROUND The finding of casual sex partners on the internet and methamphetamine use have been described as risk factors for HIV infection in men who have sex with men (MSM). However, the interplay between these factors has not been studied prospectively in one design. This study aims to determine the associations between finding casual sex partners on the internet and incident methamphetamine use and HIV infection. METHODS In this observational cohort study of Thai MSM, we recruited Bangkok residents aged 18 years or older with a history of penetrative male-to-male sex in the past 6 months. Baseline and follow-up visits were done at a dedicated study clinic in central Bangkok. Men were tested for HIV infection at every study visit and for sexually transmitted infections at baseline. Baseline demographics and HIV risk behaviour information were collected at every visit by audio computer-assisted self-interview. We used a descriptive model using bivariate odds ratios to elucidate the order of risk factors in the causal pathway to HIV incidence and methamphetamine use. We used Cox proportional hazard regression analysis to evaluate covariates for incident methamphetamine use and HIV infection. FINDINGS From April 6, 2006, to Dec 31, 2010, 1977 men were screened and 1764 were found eligible. 1744 men were enrolled, of whom 1372 tested negative for HIV and were followed up until March 20, 2012. Per 100 person-years of follow-up, incidence of methamphetamine use was 3·8 (128 events in 3371 person-years) and incidence of HIV infection was 6·0 (212 events in 3554 person-years). In our descriptive model, methamphetamine use, anal sex, and various other behaviours cluster together but their effect on HIV incidence was mediated by the occurrence of ulcerative sexually transmitted infections. Dual risk factors for both incident methamphetamine use and HIV infection were younger age and finding casual sex partners on the internet. Having ever received money for sex was predictive for incident methamphetamine use; living alone or with a housemate, recent anal sex, and ulcerative sexually transmitted infections at baseline were predictive for incident HIV infection. INTERPRETATION In MSM in Bangkok, casual sex partner recruitment on the internet, methamphetamine use, and sexually transmitted infections have important roles in sustaining the HIV epidemic. Virtual HIV prevention education, drug use harm reduction, and biomedical HIV prevention methods, such as pre-exposure prophylaxis, could help to reduce or revert the HIV epidemic among MSM in Bangkok. FUNDING US Centers for Disease Control and Prevention and the Johns Hopkins Fogarty AIDS International Training and Research Program.

Repeat HIV testing among HIV-uninfected men who have sex with men attending Silom Community Clinic, Bangkok, 2011 − 2014

Since 2010, the Thailand Ministry of Public Health has recommended that men who have sex with men (MSM) have an HIV test at least two times a year. We calculated the proportion of, and factors associated with, testing adherence among the HIV-uninfected MSM clients attending Silom Community Clinic @TropMed. We defined testing adherence as repeating at least one HIV test within six months of an initial HIV-negative test, and used log-binomial regression to test for associated factors. We included 1927 clients during 2011–2014; 362 (19%) were adherent with an increased trend (p < 0.01), from 16% to 24%. Clients aged 18–24 years and those having a history of HIV testing were more likely to adhere (aRR: 1.3, 95% CI: 1.1–1.6; and aRR: 1.3, 95% CI: 1.0–1.5, respectively). One-fifth adhered to the recommendation; older clients or naïve testees were less likely to adhere. We need to impress on clients the importance of repeat HIV testing.