THE EPIDEMIOLOGY OF HIV AND SYPHILIS AMONG MALE COMMERCIAL SEX WORKERS IN NORTHERN THAILAND

Objective: To examine the prevalence and incidence of HIV and syphilis , and risk behaviors for these infections, among 1172 male commercial sex workers (CSW) followed prospectively from 1989 to 1994 in Chiang M ai, northern Thailand. Methods: Twice yearly visits were conducted by the Thai Ministry of Public Health at all cooperating gay bars and clu bs (17 sites) in Chiang Mai City as part of a national HIV sentinel su rveillance. Men and boys who agreed were followed prospectively. Senti nel visits included an interview, HIV pre-test counseling, HIV and syp hilis serology, condom distribution, and referral for post-test counse ling. Participation was voluntary, confidential, and individual HIV re sults were available only to participating subjects. A total of 219 CS W were seen at least twice, allowing for incidence estimates based on 100 person-years (PY). Results: Median age of male CSW was 20 years. M edian time of work as a CSW was 4 months. Most men (57.6%) described t hemselves as heterosexual. Median number of clients was 2.5 per week, and reported condom use with clients was low: 42% reported inconsisten t or no condom use, while 58% reported always using condoms. Reactive Venereal Disease Research Laboratory results were 7.6%, overall, but s howed a declining trend. HIV prevalence was 1.4% in lune 1989, 13.9% i n lune 1990, and 20.1% in December 1993, and showed a significant incr easing trend. There were 27 incident HIV infections in 227.3 PY of obs ervation, for an overall incidence during the 4.5-year period of 11.9 per 100 PY (95% confidence interval, 7.42-16.38). Conclusion: Male CSW in northern Thailand are at high risk for HIV despite current prevent ion efforts. The majority are heterosexual, which may be an important epidemiologic link in the spread of HIV between male CSW users and het erosexual women in Thailand.