HIV-1 SEROCONVERSION IN A PROSPECTIVE-STUDY OF FEMALE SEX WORKERS IN NORTHERN THAILAND - CONTINUED HIGH-INCIDENCE AMONG BROTHEL-BASED WOMEN

Objectives: To determine the incidence of HIV-1 infection, temporal tr ends in incidence, and risk factors for seroconversion in a cohort of female commercial sex workers (CSW) in upper northern Thailand, the re gion of Thailand with the highest rates of HIV-1 infection. Methods: C SW were enrolled from 1991 through 1994 and evaluated prospectively wi th interviews, physical examination, testing for sexually transmitted diseases (STD), and serologic testing for HIV-1 infection. Results: Th e incidence of HIV-1 seroconversion in the first year of follow-up was 20.3 per 100 person-years among 126 brothel-based CSW and 0.7 per 100 person-years among 159 other CSW who worked in other venues such as b ars or massage parlors. Incidence remained elevated among brothel-base d CSW who were enrolled later in the study compared with those who enr olled earlier. Through 1996, 30 women seroconverted. In a multivariabl e proportional hazards model, seroconversion was significantly associa ted (P < 0.05) with brothel-based sex work (adjusted risk ratio, 7.3) and Chlamydia trachomatis cervical infection (adjusted risk ratio, 3.3 ). Conclusion: Despite national HIV control efforts and declining rate s of infection among young men in Thailand, brothel-based CSW may cont inue to be at high risk for HIV-1 infection. Additional efforts are ne eded to provide alternative economic choices for young women, to ensur e universal condom use during commercial sex, and to develop new preve ntion technologies. ISSN 0269-9370.