HIV-1 acquisition and disease progression are associated with decreased high-risk sexual behaviour among Kenyan female sex workers

BACKGROUND: Changes in sexual risk behaviour may occur following HIV-1 infection. OBJECTIVE: To test the hypothesis that HIV-1 seroconversion and disease progression are associated with changes in risk behaviours, using data from a cohort of Kenyan female sex workers (FSWs). METHODS: HIV-1-seronegative FSWs were enrolled in a prospective cohort study of risk factors for HIV-1 acquisition. At monthly visits, standardized interviews were conducted to assess sexual risk behaviour and HIV-1 serologic testing was performed. Seroconverters were invited to continue with follow-up. Between 1993 and 2004 (when antiretroviral therapy was introduced in the cohort), 265 women seroconverted for HIV-1 (incidence 7.7/100 person-years) and were included in this analysis. RESULTS: Unprotected intercourse was reported at 546/2037 (27%) pre-seroconversion visits versus 557/3732 (15%) post-seroconversion visits (P < 0.001). These findings remained significant after adjustment for potential confounding factors [adjusted odds ratio (AOR) 0.69; 95% confidence interval (CI), 0.55-0.86]. Compared with HIV-1-seronegative women, there was a progressive stepwise decrease in unprotected intercourse among HIV-1-seropositive women with CD4 cell counts > or = 500 (AOR, 0.93; 95% CI, 0.62-1.39), 200-499 (AOR, 0.58; 95% CI, 0.41-0.82) and < 200 cells/microl (AOR, 0.45; 95% CI, 0.25-0.82). Decreases in unprotected intercourse reflected increases in both abstinence and 100% condom use. Women also reported fewer partners and fewer episodes of intercourse after HIV-1 seroconversion. CONCLUSIONS: HIV-1 seroconversion and disease progression were associated with decreases in sexual risk behaviour among Kenyan FSWs.