HIV and syphilis prevalence among transgender women and men who have sex with men, Silom Community Clinic, Bangkok, Thailand, 2017-2019.

We assessed HIV and syphilis infection among MSM and TGW attending Silom Community Clinic from 2017 to 2019. Walk-in and referral clients completed a registration application including a question on gender identity. We compared the prevalence of HIV, syphilis, and HIV and syphilis coinfection among TGW and MSM. In a total of 1050 clients, 276 (26.3%) were TGW and 774 (74.7%) were MSM. Among TGW clients, HIV prevalence was 29.8%, syphilis prevalence was 38.4%, and coinfection prevalence was 18.5%. Comparing prevalence among TGW to MSM, the adjusted prevalence ratio (aPR) for HIV was 1.8 (95% CI:1.4-2.3), for syphilis was 1.2 (95% CI:1.0-1.4), and for HIV and syphilis coinfection was 2.1 (95% CI:1.4-2.9). The prevalence of syphilis was higher than HIV among TGW, with a PR of 1.3 (95% CI:1.1-1.6), and among MSM, with a PR of 1.4 (95% CI:1.2-1.7). TGW age 15-21 years had an HIV prevalence of 16.9% and syphilis prevalence of 30.8%. After adjusting for age, referral, and sexual behaviors, TGW remain significantly associated with HIV and syphilis prevalence. There is a substantial burden of HIV and HIV/syphilis co-infection among TGW. HIV/STI prevention are needed for TGW, including linkage to HIV care.

Challenges and solutions implementing an SMS text message-based survey CASI and adherence reminders in an international biomedical HIV PrEP study (MTN 017).

BACKGROUND: We implemented a text message-based Short Message Service computer-assisted self-interviewing (SMS-CASI) system to aid adherence and monitor behavior in MTN-017, a phase 2 safety and acceptability study of rectally-applied reduced-glycerin 1% tenofovir gel compared to oral emtricitabine/tenofovir disoproxil fumarate tablets. We sought to implement SMS-based daily reminders and product use reporting, in four countries and five languages, and centralize data management/automated-backup. METHODS: We assessed features of five SMS programs against study criteria. After identifying the optimal program, we systematically implemented it in South Africa, Thailand, Peru, and the United States. The system consisted of four windows-based computers, a GSM dongle and sim card to send SMS. The SMS-CASI was, designed for 160 character SMS. Reminders and reporting sessions were initiated by date/time triggered messages. System, questions, responses, and instructions were triggered by predetermined key words. RESULTS: There were 142,177 total messages: sent 86,349 (60.73%), received 55,573 (39.09%), failed 255 (0.18%). 6153 (4.33%) of the message were errors generated from either our SMS-CASI system or by participants. Implementation challenges included: high message costs; poor data access; slow data cleaning and analysis; difficulty reporting information to sites; a need for better participant privacy and data security; and mitigating variability in system performance across sites. We mitigated message costs and poor data access by federating the SMS-CASI system, and used secure email protocols to centralize data backup. We developed programming syntaxes to facilitate daily data cleaning and analysis, and a calendar template for reporting SMS behavior. Lastly, we ambiguated text message language to increase privacy, and standardized hardware and software across sites, minimizing operational variability. CONCLUSION: We identified factors that aid international implementation and operation of SMS-CASI for real-time adherence monitoring. The challenges and solutions we present can aid other researchers to develop and manage an international multilingual SMS-based adherence reminder and CASI system.

Randomized Controlled Trial to Compare Immunogenicity of Standard-Dose Intramuscular Versus Intradermal Trivalent Inactivated Influenza Vaccine in HIV-Infected Men Who Have Sex With Men in Bangkok, Thailand.

BACKGROUND: Individuals infected with human immunodeficiency virus (HIV) are at increased risk for severe influenza, yet immune responses to standard-dose intramuscular (IM) influenza vaccine are suboptimal in this population. Intradermal (ID) delivery of influenza vaccine might improve immune response through enhanced stimulation of dendritic cells. METHODS: We conducted a randomized, double-blind, controlled trial to compare the immunogenicity of off-label standard-dose (15 µg) ID vs standard-dose (15 µg) IM inactive influenza vaccine in HIV-infected men in Bangkok, Thailand. The primary study outcome was seroconversion (minimum titer of 1:40 and ≥4-fold rise in antibody titer) at 1 month postvaccination based on serum hemagglutination inhibition antibody titers against each vaccine strain. Adverse events (AEs) in the 7 days following vaccination were also assessed. RESULTS: We enrolled 400 HIV-infected participants; 200 were randomly assigned to receive IM and 200 ID vaccine. Vaccine arms were well-balanced with respect to age, CD4 cell count, HIV RNA load, and antiretroviral treatment. Percentage of seroconversion to all (ID 14% vs IM 15%; P = .8) or at least 1 (ID 69% vs IM 68%; P = .7) of the 3 vaccine strains did not differ significantly between ID vs IM vaccine recipients. A higher proportion of participants who received ID vaccine had mild injection-site AEs compared with participants who received IM vaccine (77% vs 27%). CONCLUSIONS: There were no significant differences in the immunogenicity of standard-dose ID vs IM influenza vaccine in this HIV-infected population in Thailand. Additional strategies to enhance immune responses to influenza vaccine among HIV-infected persons are needed. CLINICAL TRIALS REGISTRATION: NCT01538940.

Infective endocarditis in northeastern Thailand.

Despite rigorous diagnostic testing, the cause of infective endocarditis was identified for just 60 (45.5%) of 132 patients admitted to hospitals in Khon Kaen, Thailand, during January 2010-July 2012. Most pathogens identified were Viridans streptococci and zoonotic bacteria species, as found in other resource-limited countries where underlying rheumatic heart disease is common.

Prevalence and correlates of willingness to participate in a rectal microbicide trial among men who have sex with men in Bangkok.

Rectal microbicides (RMs) hold promise as a HIV prevention method to reduce transmission among men who have sex with men (MSM). To assess RM trial feasibility in Bangkok, we measured prevalence and correlates of willingness to participate among Thai MSM observational cohort participants. Between April 2006 and December 2010, 1744 MSM enrolled in the Bangkok MSM Cohort Study; at 12 months, RM trial participation willingness was measured. We evaluated correlates of RM trial participation willingness using logistic regression analysis. Participants completing the 12-month visit (81.4%, n = 1419) had a mean age of 27.3 years (SD = 6.1), and 65.5% and 86.1% reported having a steady partner or anal intercourse (AI) in the past four months, respectively. Most (79.1%, n = 1123) participants reported willingness to participate in an RM trial, which, in multivariable analysis, was independently associated with insertive only (adjusted odds ratio [AOR] = 3.25, 95% CI: 1.82-5.81) or receptive/versatile role AI (AOR = 3.07, 95% CI: 1.88-5.01), and being paid for sex (AOR = 12.15, 95% CI: 1.67-88.21) in the past four months, and believing that people with AIDS look sick (AOR = 1.92, 95% CI: 1.23-2.98). Of hypothetical RM trial features to increase enrollment likelihood, the most (91.1%) compelling was that the study be approved by the Thai ethics committee, followed by the study site offering evening hours (88.9%). Reasons not to participate were not wanting a rectal examination (29.5%) or fluid collected from the penis or anus (24.6%) and not wanting the placebo (23.0%). RM trial participation willingness was high, particularly for those with greater HIV acquisition risk, within this Thai MSM cohort, suggesting feasibility of an RM trial. Addressing potential barriers to trial entry may be useful in educational materials to optimize recruitment.

Development of a diagnosis disclosure model for perinatally HIV-infected children in Thailand.

While disclosure of HIV status to perinatally HIV-infected children has become an increasingly important clinical issue, specific disclosure guidelines are lacking. We developed a pediatric HIV diagnosis disclosure model to support caretakers. All HIV-infected children greater than 7-years-old at two participating hospitals in Bangkok, Thailand, and their caretakers, were offered disclosure according to the 4-step protocol: (1) screening; (2) readiness assessment; (3) disclosure; and (4) follow-up. Disclosure occurred after agreement of both providers and caretakers. Among 438 children who were screened, 398 (89%) were eligible. Readiness assessment was completed for 353 (91%) of eligible children and 216 (61%) were determined ready. Disclosure was done for 186 children. The mean age at eligibility screening was 10.5 years (range: 6.8-15.8 years); the mean age at disclosure was 11.7 years (range: 7.6-17.7 years). The mean duration between eligibility screening and disclosure was 15.2 months. There were no significant negative behavioral or emotional outcomes reported in children following disclosure. This HIV diagnosis disclosure model was feasible to implement and had no negative outcomes. As the time for preparation process was over 1 year for most cases, the disclosure process can be initiated as early as age 7 to allow enough time for disclosure to be completed by the age of adolescence.

High PrEP uptake, adherence, persistence and effectiveness outcomes among young Thai men and transgender women who sell sex in Bangkok and Pattaya, Thailand: findings from the open-label combination HIV prevention effectiveness (COPE) study.

Background: Daily oral pre-exposure prophylaxis (PrEP) is effective in preventing HIV infection, but no study has evaluated combination prevention interventions with PrEP for transgender women (TGW) and men who have sex with men (MSM) who sell sex. Methods: The Combination Prevention Effectiveness (COPE) study was a community-based, non-randomized implementation study in Bangkok and Pattaya, Thailand. Participants were HIV-negative MSM and TGW aged 18-26 years who reported exchanging sex with men in the prior 12 months and who met 2014 U.S. Public Health Service PrEP eligibility criteria. The intervention included quarterly HIV testing, semiannual testing for sexually transmitted infections, provision of condoms with lubricant, and the opportunity to initiate or end daily oral PrEP use at any time during study participation. Participants taking PrEP received monthly adherence counseling and short message service reminders. The primary outcome was HIV incidence rate ratio (IRR) on PrEP vs. not on PrEP. Secondary outcomes were PrEP initiation, PrEP use at 12 months, and PrEP adherence. Findings: From October 2017 to August 2019, 846 participants were enrolled: 531 (62.8%) immediately initiated PrEP; 104 (12.3%) subsequently initiated PrEP, and 211 (24.9%) never initiated PrEP. Among those initiating PrEP within 30 days of enrollment; 85.9% were on PrEP at the 12-months. When taking PrEP, participants reported adherent PrEP use at 94.2% of quarterly assessments. Ten HIV seroconversions occurred without PrEP use (incidence rate [IR] = 3.42 per 100 person-years [PY]; 95% CI = 1.64-6.30), while zero cases occurred with PrEP use (IR = 0.0 per 100PY; 95% CI = 0.0-0.62), with IRR = 0.0 (95% CI = 0.0-0.22; p < 0.001). Interpretation: Young Thai MSM and TGW who exchange sex can have high PrEP uptake, persistence and adherence, and low HIV incidence when offered in supportive community-based settings. Funding: U.S. National Institute of Allergy and Infectious Diseases; Centers for Disease Control and Prevention.

Transactional sex, HIV and health among young cisgender men and transgender women who have sex with men in Thailand.

PURPOSE: To examine how recent sex work is identified and the HIV risk factors and service needs among Thai cisgender men who have sex with men (MSM) and transgender women (TGW) who exchange sex. METHODS: MSM and TGW in Bangkok and Pattaya who exchanged sex in the last year (n = 890) were recruited through social media, outreach, and word-of-mouth. Recent sex exchange was based on the primary question, "In the last 30 days, have you sold or traded sex"; secondary questions (regarding income source and client encounters) were also investigated. RESULTS: Overall, 436 (48%) participants engaged in sex work in the last 30 days; among those, 270 (62%) reported exchanging sex by the primary question, and 160 (37%) based on secondary questions only. Recent sex exchange was associated with gonorrhea, syphilis, discussing PrEP with others, and using condoms, alcohol, methamphetamine, amyl nitrate, and Viagra. Exchanging sex based on secondary questions only was associated with being in a relationship, social media recruitment, less recent anal intercourse, and not discussing PrEP. CONCLUSIONS: Thai MSM and TGW who exchange sex need regular access to HIV/STI prevention, testing, and treatment services, and multiple approaches to assessing sex work will help identify and serve this diverse and dynamic population.

Antiretroviral treatment initiation among HIV-positive participants in the Bangkok men who have sex with men cohort study, 2006-2016.

INTRODUCTION: Data on HIV antiretroviral therapy (ART) initiation among key-affected populations will support reaching the UNAIDS goal to end AIDS by 2030. METHODS: We assessed ART initiation among HIV-positive participants of the Bangkok Men Who Have Sex with Men (MSM) Cohort Study, which enrolled sexually experienced MSM aged ≥ 18 years and included visits every four months for a period of 3-5 years, from 2006-2016. At each visit, participants had HIV testing and completed computer-assisted self-interviewing on demographics and HIV risk behaviors. If they acquired HIV infection during the study, they received active referral for HIV treatment, continued in the cohort, and were asked about ART initiation. We used logistic regression to determine factors associated with ART initiation. RESULTS: Overall, 632 (36.2%) participants were diagnosed with HIV infection; 463 (73%) had a follow-up visit reporting information about ART, of those 346 (74%) reported ART initiation, with 323 (93%) on ART initiating ART through their registered national health benefit program. Only 70 (11%) were eligible for ART at time of diagnosis, and 52 (74%) initiated ART, on average, within six months of diagnosis. Multivariable analysis evaluating factors associated with ART initiation demonstrated that low CD4 cell count at time of diagnosis was the only independent factor associated with ART initiation. CONCLUSIONS: Most HIV-positive participants in the cohort reported ART initiation through the national health benefit program but limited data suggests there could be improvements in length of time to initiation of ART. Efforts should focus on ART start in MSM and transgender women soon after HIV diagnosis.

Recent declines in HIV infections at Silom Community Clinic Bangkok, Thailand corresponding to HIV prevention scale up: An open cohort assessment 2005-2018.

OBJECTIVES: We assessed HIV-1 infection among men who have sex with men (MSM) attending Silom Community Clinic (SCC) in Bangkok, Thailand from 2005 to 2018. Since 2014, Thailand increased implementation of HIV prevention strategies including pre-exposure prophylaxis and Treatment as Prevention. METHODS: MSM attending SCC were tested for HIV using rapid tests. We assessed trends in HIV prevalence, incidence and compared incidence before and after 2014. RESULTS: From 2005 to 2018, 14,034 clients attended SCC for HIV testing. The HIV prevalence increased from 19.2% in 2005-2006 to 34-0% in 2010, remained stable until 2016 and decreased to 17.2% in 2018 (p<0.0001). The HIV incidence was 4.1 per 100 person-years (PY), with an inverted U-shape trend and a peak in 2009 (p<0.0001). Incidence among young MSM aged 13-21 years remained high at 10.0 per 100 PY. Among those aged 22-29 years, lower incidence was found from Q 3 2016, with a relative risk reduction of 46.2% (p<0.001); and a similar reduction among those aged ≥30 years from Q4 2014, corresponding to scale up of HIV prevention strategies. CONCLUSION: We found a decline in HIV infection among Thai MSM. However, incidence remained high among young MSM.

Spatial characteristics of men who have sex with men and transgender women attending HIV voluntary counselling and testing in Bangkok, Thailand, 2005-2015.

Spatiotemporal analyses can support Human Immuno-deficiency Virus (HIV) prevention programmes by identifying locations of at-risk populations in space and time, and their proximity to HIV testing and prevention services. We assessed residential proximity to HIV testing venues for Men who have Sex with Men (MSM) and Transgender Women (TGW) attending Voluntary Counselling and Testing (VCT) at a large urban MSM clinic in Bangkok, Thailand in the period 2005-2015. We mapped clientprovided spatial data and HIV testing venues, calculating distance from residence to venues for VCT clients between i) September 2005-December 2009; ii) January 2010-September 2013; and iii) October 2013-May 2015. We assessed spatial characteristics across times, evaluating autocorrelation of HIV prevalence and visit density using Moran's I. Among 8,758 first-time VCT clients reporting geographic information from 2005-2015 (by period: 2737, 3917, 2104), 1329 (15.2%) lived in postal codes ≤5 km from the clinic. Over time, the proportion living in areas covered by Bangkok postal codes ≤2 km from any MSM HIV testing venue increased from 12.6% to 41.0% (p<0.01). The proportion living ≤5 km from the clinic decreased from 16.6% to 13.0% (p<0.01). HIV prevalence and clinic visit density demonstrated statistically significant non-random spatial patterning. Significant non-random patterning of prevalent infection and client visits highlighted Bangkok's urban HIV epidemic, clinic proximity to clients, and geographic reach. Clients lived closer to testing venues, yet farther from the urban MSM clinic, over time. Spatiotemporal characteristics of VCT clients can help assess service accessibility and guide targeted prevention planning.

Estimating the impact of HIV combination prevention in men who have sex with men, the Bangkok MSM Cohort Study, Thailand.

In Thailand, pre-exposure prophylaxis (PrEP) is recommended for human immunodeficiency virus (HIV) prevention among at-risk men who have sex with men (MSM). We modeled the impact of PrEP and condom use as independent and combined interventions on the estimated number of HIV infections among a hypothetical population of 10,000 MSM in Bangkok, Thailand. Our model demonstrated a 92% (95% confidence interval 89.7, 94.2) reduction in HIV infections among Thai MSM who took daily PrEP and self-reported using condoms correctly and consistently (100% condom use). Increased use of PrEP and condoms likely would have a substantial impact on the HIV epidemic in Thailand.

The first year of the global Enhanced Gonococcal Antimicrobial Surveillance Programme (EGASP) in Bangkok, Thailand, 2015-2016.

Antimicrobial-resistant Neisseria gonorrhoeae (NG) infection is a global public health threat, and there is a critical need to monitor patterns of resistance and risk factors. In collaboration with the World Health Organization (WHO), the U.S. Centers for Disease Control and Prevention (CDC), and the Thailand Department of Disease Control (DDC), Ministry of Public Health (MoPH) implemented the first Enhanced Gonococcal Antimicrobial Surveillance Programme (EGASP) in November 2015. Men presenting with urethritis at two clinical settings in Bangkok, Thailand (Bangrak Hospital [BH] and Silom Community Clinic @TropMed [SCC @TropMed]) provided demographic and behavioral information and had a urethral swab for Gram's stain and NG culture collected. The NG isolates were evaluated for antimicrobial susceptibility by the Epsilometer test (Etest) to determine minimum inhibitory concentrations (MICs) for cefixime (CFM), ceftriaxone (CRO), azithromycin (AZI), gentamicin (GEN), and ciprofloxacin (CIP). From November 2015 -October 2016, 1,102 specimens were collected from 1,026 symptomatic men; 861 (78.1%) specimens were from BH and 241 (21.9%) specimens were from SCC @TropMed. Among the 1,102 specimens, 582 (52.8%) had intracellular Gram-negative diplococci and 591 (53.6%) had NG growth (i.e., NG infection); antimicrobial susceptibility testing (AST) was performed on 590 (99.8%) NG isolates. Among all symptomatic men, 293 (28.6%) had sex with men only, 430 (41.9%) were ages 18-29 years, 349 (34.0%) had antibiotic use in the last 2 weeks, and 564 (55.0%) had NG infection. Among 23 men with repeat NG infection during this first year of surveillance, 20 (87.0%) were infected twice, 2 (8.7%) were infected three times, and 1 (4.3%) was infected more than four times. All NG isolates were susceptible to CFM and CRO, and had MICs below 2 µg/mL for AZI and below 16 µg/mL for GEN. Overall, 545 (92.4%) isolates were resistant to CIP. This surveillance activity assessed individual patients, and included demographic and behavioral data linked to laboratory data. The inclusion of both individual and laboratory information in EGASP could help identify possible persistent infection and NG treatment failures. Expansion of EGASP to additional global settings is critical to assess trends and risk factors for NG, and to monitor for the emergence of resistance.

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 2011­2014; 362 (19%) were adherent with an increased trend (p < 0.01), from 16% to 24%. Clients aged 18­24 years and those having a history of HIV testing were more likely to adhere (aRR: 1.3, 95% CI: 1.1­1.6; and aRR: 1.3, 95% CI: 1.0­1.5, 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.

Lubricant Use Among Men Who Have Sex With Men Reporting Anal Intercourse in Bangkok, Thailand: Impact of HIV Status and Implications for Prevention.

This analysis measures prevalence and correlates of consistent lubricant use among a cohort of Thai men who have sex with men (MSM). Lubricant use was queried at the 12-month follow-up visit. Consistent lubricant use was evaluated with logistic regression. Consistent lubricant use was reported by 77.0% of men and was associated with consistent condom use with casual partners, while binge drinking, payment for sex, and inconsistent condom use with casual, and steady, partners were negatively associated. Though consistent lubricant use is common among this Thai MSM cohort, further promotion is needed with MSM engaging in risky sexual practices.

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.

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.

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.

BACKGROUND: Daily 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. METHODS: We 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. RESULTS: Of 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 (approximately 30%) was more often reported than sex on weekdays (approximately 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. CONCLUSIONS: Intermittently 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.