Feasibility of Identifying a Female Sex Worker Cohort at High Risk of HIV Infection in the Caribbean for HIV Vaccine Efficacy Trials: Longitudinal Results of HVTN 907.

Background: Identifying cohorts of Caribbean women with HIV infection rates sufficient for inclusion in HIV vaccine efficacy trials has been challenging. HVTN 907 determined the feasibility of identifying and retaining a cohort of women at high risk for HIV acquisition by focusing recruitment on female sex workers (FSWs).

Methods: HIV uninfected FSWs, residing in Haiti, Dominican Republic, and Puerto Rico, who reported unprotected sex and met previously described more stringent site-specific eligibility criteria, were eligible. Behavioral risk assessment, HIV counseling and testing, and pregnancy testing were performed at baseline, 6, 12, and 18 months.

Results: Among 799 FSWs (264 from Dominican Republic, 334 from Haiti, and 201 from Puerto Rico), the median age was 26 years, with 54% having less than a high school education and 45% having a monthly household income of less than $US 100. Median number of male partners 6 months before screening was 200. Retention at 18 months was 93%. Twelve women became HIV infected, 9 from Haiti. The annualized HIV incidence was 1.07% (95% confidence interval: 0.55% to 1.87%). Pregnancy incidence was 22.5% (95% confidence interval: 21.9% to 29.5%). Statistically significant declines in risk behaviors occurred between screening and the 18-month visit assessment.

Discussion: The HVTN 907 study identified a high-risk cohort of women with excellent retention for all 3 sites, despite major challenges especially in Haiti. These results show that a bridging study of a vaccine shown to be efficacious in other clade settings would be possible among FSWs in the region, particularly in Haiti.