Cohort Analysis of Program Data to Estimate HIV Incidence and Uptake of HIV-Related Services Among Female Sex Workers in Zimbabwe, 2009-2014
Background: HIV epidemiology and intervention uptake among female sex workers (FSW) in sub-Saharan Africa remain poorly understood. Data from outreach programs are a neglected resource.
Methods: Analysis of data from FSW consultations with Zimbabwe's National Sex Work program, 2009-2014. At each visit, data were collected on sociodemographic characteristics, HIV testing history, HIV tests conducted by the program and antiretroviral (ARV) history. Characteristics at first visit and longitudinal data on program engagement, repeat HIV testing, and HIV seroconversion were analyzed using a cohort approach.
Results: Data were available for 13,360 women, 31,389 visits, 14,579 reported HIV tests, 2750 tests undertaken by the program, and 2387 reported ARV treatment initiations. At first visit, 72% of FSW had tested for HIV; 50% of these reported being HIV positive. Among HIV-positive women, 41% reported being on ARV. 56% of FSW attended the program only once. FSW who had not previously had an HIV-positive test had been tested within the last 6 months 27% of the time during follow-up. After testing HIV positive, women started on ARV at a rate of 23/100 person years of follow-up. Among those with 2 or more HIV tests, the HIV seroconversion rate was 9.8/100 person years of follow-up (95% confidence interval: 7.1 to 15.9).
Conclusions: Individual-level outreach program data can be used to estimate HIV incidence and intervention uptake among FSW in Zimbabwe. Current data suggest very high HIV prevalence and incidence among this group and help identify areas for program improvement. Further methodological validation is required.