HIV-1 SEROCONVERSION RATES AMONG FEMALE COMMERCIAL SEX WORKERS, CHIANG-MAI, THAILAND - A MULTI CROSS-SECTIONAL STUDY

Objectives: To determine HIV seroconversion rates among female commerc ial sex workers (CSW) in Chiang Mai, Thailand. Design: A three-round m ulti cross-sectional study was used at approximately 3-month intervals . Methods: In December 1989, 38 brothels (60%) in Chiang Mai were rand omly selected. All 518 female CSW in the brothels were interviewed abo ut their sociodemographics, sexual practices, condom use, history of s exually transmitted diseases (STD) and other risk factors. Blood was t ested for Venereal Disease Research Laboratory (VDRL)-reactivity and H IV-1 antibody. The same brothels, which were all still operating, were revisited in March and July 1990 and 431 and 320 CSW, respectively, w ere interviewed and blood-tested. Pelvic examination, cervical, urethr al and rectal cultures for gonococcus were added to the study in March 1990, although rectal culture was dropped from the study in July 1990 . Results: There were 5.2% [95% confidence interval (Cl), 4.1-10.6] an d 3.6% (95% Cl, 1.5-5.4) per woman-month HIV seroconversion rates for the December-March and March-July periods, respectively. Of the CSW, 7 1.6-77.0% reported histories of at least one STD. Condom-use rates amo ng these CSW were reported to be 85.8-91.8%. High rates of positive ce rvical (11.2-12.3%) and urethral (8.8-11.4%) cultures for gonococcus w ere also found in the CSW. Conclusions: The fact that high HIV serocon version rates and high STD prevalence rates occur despite high rates o f reported condom use suggests that more aggressive education programs are needed in Thailand.