HIV prevalence and incidence among FSWs participating in a HIV vaccine preparedness study in Dar es Salaam, Tanzania

Background: PrEPVacc is a phase IIb multicenter HIV vaccine trial planned to be conducted at five sites in four sub-Saharan African countries that aims to evaluate safety and efficacy of two combinations of HIV vaccine regimens; HIV DNA + gp120/alum and HIV DNA, MVA + gp140/MPLA. A PrEPVacc HIV-negative registration cohort study was established to determine HIV prevalence and incidence among female sex workers (FSW) in Dar es Salaam, Tanzania. Methods: Between October and December 2018, a total of 773 FSW aged 18-45 years were screened for eligibility and 700 were enrolled. At screening and at 3-monthly follow-up visits, demographics and risky behavioural assessment and collection of blood samples were done. HIV testing was performed using two sequential rapid diagnostic tests; SD Bioline HIV1/2 and Uni-Gold HIV-1/2. HIV reactive samples were confirmed using Siemens Enzygnost HIV Integral 4 ELISA. Logistic regression was used to estimate odds Ratios for factors associated with HIV prevalence. Time-to-event analysis was performed using Poisson regression to estimate HIV incidence. Women were censored at 12 months of follow-up or earliest date of HIV seroconversion. Date of seroconversion was assumed to be midway between last negative and first positive HIV test results. Results: HIV prevalence at screening was 8% (59/773), associated with older age (p < 0.001), lower education levels (p < 0.001) and being single (either never married or separated/divorced/widowed) (p < 0.001). FSWs who reported being raped or having used drugs, were more likely be HIV-infected than their counterparts (p = 0.01 and p = 0.002, respectively). Attendance at 12 months was 80% (560/700) with women in the cohort contributing a total of 609 person-years-at risk (PYR). Twenty-one FSWs seroconverted with the HIV incidence rate in the cohort of 3.45 per 100 PYRS (95% CI; 2.25 to 5.28/100 PYRS). Conclusions: HIV prevalence and incidence were high among FSW in Dar es Salaam. These findings demonstrate feasibility of recruiting FSW for HIV vaccine prevention trials.
OA02.04 D. Faini (1); F. Msafiri (2); P. Munseri (3); M. Bakari (4); A. Joachim (2); T. Nagu (3); E. Tarimo (5); E. Lyamuya (2); E. Sandstrom (6); G. Biberfeld [...]