Derivation of an HIV Risk Score for African Women Who Engage in Sex Work

No tool exists to stratify HIV risk in contemporary African female sex worker (FSW) populations. Data from a cohort of HIV-negative FSWs in Mombasa, Kenya from 2010 to 2017 were used to conduct a survival analysis assessing predictors of HIV infection. Stepwise regression was used to construct a multivariable model that formed the basis for the score. Seventeen HIV infections occurred over 1247 person-years of follow-up contributed by 670 women. Using depot medroxyprogesterone acetate (DMPA), having a curable sexually transmitted infection (STI), and being married contributed points to the score. HIV incidence was 0.85/100 person-years in a lower-risk group and 3.10/100 person-years in a higher-risk group. In a cohort with overall HIV incidence < 1.50/100 person-years, this risk score identified a subgroup of FSWs with HIV incidence > 3.00/100 person-years, which is the threshold used by the World Health Organization for initiating pre-exposure prophylaxis (PrEP). If validated in an external population, this tool could be useful for targeted PrEP promotion among higher-risk FSWs.