Quantifying delay in first contact with HIV programs among young women engaged in sex work in Mombasa, Kenya: a time-to-event analysis

Background: Young women engaged in sex work (YSW) experience a disproportionately high burden of HIV, yet most HIV programs for sex workers are not designed to reach adolescent girls and young women. Methods: Longitudinal data from the start of sex work are infeasible, but cross-sectional surveys may help identify contact gaps. We used data from the 2015 Transitions Study, a cross-sectional survey of sexually active women aged 14-24 who self-identified as a sex worker in Mombasa, Kenya. We created a virtual cohort using self-reported event timing described relative to the survey date. We quantified the time from self-identification as sex worker to the initial program contact (contact gap) and employed time-to-event analyses to estimate and characterize factors associated with the rate of program contact. Results: Of 392 YSW, 47 (12%) reported program contact, with a median time of 12 months (interquartile range: 2, 24). The rate of program contact per 100 person-months was 0.52 [95% confidence interval (CI): 0.38, 0.68], and when applied to the estimated population size of YSW in Mombasa, the minimum access gap was 11,532 person-years. A shorter contact gap was associated with: older age when first negotiated for sex (adjusted hazard ratio:1.2 [95%CI: 1.0, 1.5]); and self-perceived ease of earning money through sex work (11.5 [2.8, 47.7]). Conclusion: A large contact gap highlights the need to reshape HIV prevention services for YSW across their life course. Despite limitations, cross-sectional data could help estimate the contact gap and support program monitoring and evaluation.