Prevalenceand Estimated Size Of HIV/AIDS Among Active Men Who Have Sex With Men In Zhanjiang City

[Objectives]To understand the HIV epidemic among active men who have sex with men(MSM)in Zhanjiang City, to estimate the population size of MSM in the city and to estimate the number of MSM who live with Human Immunodeficiency Virus(HIV) infections in Zhanjiang City, and thus to provide scientific basis for drawing up prevention and control strategies and health resources allocation.[Methods]A cross-sectional survey was undertaken to understand the characteristics, risk behaviors as well as HIV prevalence among MSM in Zhanjiang City. Capture-recapture method using fourcaptures with different markers was adopted to estimate the population size of active MSM, in both actual and virtual venues. The HIV prevalence and the size of MSM population were then combined to estimate the number of MSMwith HIVinfectionin Zhanjiang.[Results]A total of 421 MSM participantswere recruited in the cross-sectional survey, among which 82.9% were recruited from network and 17.1% from actual venues. 76.5% of the participants aged 20-30 years, 70.5% being unmarried, 59.6% having had residence period of more than two years, and 39.2% having education level of junior middle school or below. The percentage of awareness about AIDS was 78.4%. The proportion that used condom for the last homosexual anal sex was 65.8%. The proportion of consistent condom use during the last six months was 22.0% and 9.3% of the participants had had sex with females during the last six months.The HIV prevalence among the active MSM in Zhanjiang was 5.2%. The HIV prevalence among various age groups wasstatistically different(P<0.001). By using four captures with fourdifferent markers, it was estimated that there were about 7116 MSM in Zhanjiang City(95% CI:4600~9632), which was accounted for about 1.4% of the local male sexually active population(95%CI:0.9%~1.8%. In total it was estimated that there were 370 persons living with HIV among the local active MSM population(95%CI:240~501).[Conclusion]1. The HIV prevalence had reached a relatively high level among MSM in Zhanjiang,with a large size of MSM, suggesting that the HIV/AIDS propaganda and education and effective behavior intervention need to be strengthened and expanded.2. In Zhanjiang City, the characteristics of active MSM population basically met the key assumptions of capture-recapture method, which provided a new idea in comprehensive estimate of MSM population. Multiple markers should be considered in future studies.