HIV-1 seroconversion in a prospective study of female sex workers in northern Thailand: continued high incidence among brothel-based women

AIDS. 1998 Oct 1;12(14):1889-98. doi: 10.1097/00002030-199814000-00021.


Objectives: To determine the incidence of HIV-1 infection, temporal trends in incidence, and risk factors for seroconversion in a cohort of female commercial sex workers (CSW) in upper northern Thailand, the region of Thailand with the highest rates of HIV-1 infection.

Methods: CSW were enrolled from 1991 through 1994 and evaluated prospectively with interviews, physical examination, testing for sexually transmitted diseases (STD), and serologic testing for HIV-1 infection.

Results: The 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 bars or massage parlors. Incidence remained elevated among brothel-based CSW who were enrolled later in the study compared with those who enrolled earlier. Through 1996, 30 women seroconverted. In a multivariable proportional hazards model, seroconversion was significantly associated (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 rates of infection among young men in Thailand, brothel-based CSW may continue to be at high risk for HIV-1 infection. Additional efforts are needed to provide alternative economic choices for young women, to ensure universal condom use during commercial sex, and to develop new prevention technologies.

MeSH terms

  • Adolescent
  • Adult
  • Female
  • HIV Infections / diagnosis
  • HIV Infections / epidemiology*
  • HIV Seropositivity*
  • HIV-1*
  • Humans
  • Incidence
  • Male
  • Prospective Studies
  • Risk Factors
  • Sex Work*
  • Sexual Behavior
  • Sexually Transmitted Diseases / diagnosis
  • Sexually Transmitted Diseases / epidemiology
  • Thailand / epidemiology