Setting and Population

This study is a secondary analysis including HIV-negative FSWs from 7 sites, which formed the intervention arm of the Sisters Antiretroviral Programme for Prevention of HIV: an Integrated Response (SAPPH-IRe) trial. This was a cluster (site)-randomized trial of an enhanced HIV care and prevention package for FSWs in 14 sites reflecting different sex work location types, including towns, growth points, collieries, and army bases. In all sites, the national sex work “Sisters with a Voice” programme (Sisters) provided free condoms and contraception, HIV testing and counseling, syndromic management of STIs, health education, community mobilization, and legal advice. In the 7 intervention sites, community mobilization was enhanced, clinical services to initiate ART and PrEP were available onsite, and community-based support for ART and PrEP adherence was provided. PrEP was offered to all women testing HIV-negative from July 2014 (November 2014 in one site) until endline in May 2016, along with a peer-based support programme and active follow-up. At this time in Zimbabwe, the SAPPH-IRe trial was the only way FSWs could access PrEP.

Cross-sectional respondent-driven sampling (RDS) surveys of approximately 200 women per site were conducted at study endline, with sample size determined by the primary trial outcome.²⁶ Women were eligible if they had sold sex for money in the past 30 days, were aged 18 or older, and had been living/working in the site for 6 months. Because SAPPH-IRe was a pragmatic trial, we used RDS to obtain population-representative estimates among FSWs at each site to assess the impact of the intervention on the FSW population as a whole, not only those who had had some contact with the enhanced Sisters intervention. We describe detailed procedures elsewhere.²⁷ Following mapping at each site, we purposefully selected initial “seeds” of 6 or 8 women, issued 2 coupons for recruitment, and reached 5 sample waves. Interviewers administered the questionnaire and entered data onto tablet computers, uploaded to a master database daily. A capillary blood sample was collected on dried blood spot for HIV antibody testing and, if reactive, HIV viral load measured.