Entry into sex work and HIV pre-exposure prophylaxis uptake and adherence in Female Sex Workers in Nairobi, Kenya – a mixed-methods exploration of cross-sectional data.

Female sex workers (FSWs) in Kenya face a significant HIV burden and are often subjected to stigma, discrimination, and violence, especially if they initiate sex work at a young age. Despite the availability of HIV prevention programs, including oral pre-exposure prophylaxis (PrEP), uptake and adherence remain low, resulting in persistently high HIV prevalence among FSWs compared to the general female population. The aim of this thesis was to explore factors shaping entry into sex work and the subsequent PrEP uptake and adherence.

This research was nested within the Maisha Fiti study, a longitudinal study among FSWs aged 18-45 years. Baseline data were collected from 1003 FSWs, and 48 participated in in-depth interviews. Using a life course perspective, this thesis explored the intersection of structural, interpersonal, and individual factors influencing early lives of FSWs and factors associated with uptake of, and adherence to oral PrEP. First, qualitative interviews were analysed thematically using a syndemic lens to explore early experiences. Second, factors associated with early (<18 years of age) compared to later (18 years and over) sex work entry, and third, factors associated with oral-PrEP adherence among HIV-negative FSWs, were investigated using hierarchical logistic regression informed by a social-ecological model. PrEP adherence was measured using a novel urine tenofovir immunoassay and compared to self-report.

Qualitative analysis revealed that pathways into sex work were shaped by poverty, limited education, childhood violence, and early pregnancy or marriage, which led to the development of a conceptual framework for understanding sex work initiation in Kenya. Quantitative analysis found that incomplete education, childhood violence, homelessness, and early sexual debut were associated with early sex work entry. Investigation into PrEP usage among FSWs revealed low uptake and adherence, but factors associated with increased adherence included a lower education level, having a higher wealth tertile, experiencing childhood emotional violence, and not having children.

These findings provide novel insights into the interplay of co-factors across the life course in shaping initiation into sex work and PrEP adherence as well as the measurement of PrEP adherence among FSWs, highlighting the need for tailored interventions and policy measures to improve their health and well-being in Kenya.