Abstract
Background: Female sex workers (FSW) face systemic discrimination making them vulnerable to poor health and wellbeing. Current HIV prevention strategies and local community-based programs rely on estimates of the size of key populations, like FSW, to plan and provide differentiated HIV prevention services. In addition, local community-based programs rely on size estimates to address the often unequal access to services for FSW. However, there are no systematic assessments of the number of FSW in sub-Saharan Africa to facilitate identification of HIV prevention and treatment gaps.
Methods: We estimated FSW population sizes and the corresponding uncertainties for almost all sub-national areas in sub-Saharan Africa. We performed a literature review of FSW size estimates and identified 932 subnational FSW population size estimates from 33 of the 44 sub- Saharan African countries from 2000 to 2018. We developed a Bayesian hierarchical model to synthesize these size estimates, resolving competing size estimates in the same area and producing reliable estimates in new areas.
Findings: We estimate that there are 2·130 million (95% uncertainty interval 1·219-3·612) FSW of childbearing age in sub-Saharan Africa. This represents a proportion as percent of all women of childbearing age of 0·905%. The estimated FSW proportion at the national level ranges from 0·294% in Togo to 2·158% in Namibia. Our analyses also reveal substantial differences between the proportions of FSW among adult females at the sub-national level. Several predictors that explain these heterogeneities were identified, and estimate uncertainty decreases as data availability increases.
Interpretation: The percent of sub-national areas in sub-Saharan Africa with FSW size estimates is low, making it difficult to perform evidence-based resource allocation for HIV and other health services. We produced size estimates in the remaining areas and reconciled competing estimates. However, many estimates are based solely on modelled extrapolations and therefore have large uncertainty. Continued and improved efforts to estimate FSW population sizes at the sub-national level is vital to design and evaluate effective programs for FSW.
Funding Statement: NIH/NIAID 5R01AI136664