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]) X 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.