“I Stopped to Prove them Wrong:” Reasons for Discontinuing Daily Oral HIV Pre-exposure Prophylaxis Among Women at High Risk of HIV in Tanzania—A Convergent Mixed Methods Study

High discontinuation of pre-exposure prophylaxis (PrEP) among high-risk women undermines its effectiveness. However, there is limited evidence on the reasons for PrEP discontinuation among female sex workers in sub-Saharan Africa. Exploring population-specific reasons for PrEP discontinuation will guide the design of client-centered strategies. Thus, we explored the reasons for PrEP discontinuation among female sex workers in Tanzania using mixed methods from 2022 to 2023 in Tanga, Tanzania. Participants were recruited through respondent-driven sampling and followed up for 12 months, and quantitatively interviewed at months 1, 6, and 12. In-depth interviews were carried out alongside the 12-month survey with purposely sampled female sex workers who had discontinued PrEP. Separate descriptive (and log-binomial regression) and thematic analyses were performed, and the insights were compared and integrated. We enrolled 313 participants with a median age of 27 years (IQR: 23-32). At 6 months, 61.5% (95% CI 54.3-68.4) had stopped taking PrEP for ≥ 3months, increasing to 67.4% (95% CI 60.2-74.0) at 12 months. Self-perceiving to be at "medium" to "high" risk of HIV had a 20% lower risk of stopping PrEP for ≥ 3months compared to self-perceiving to be at low or no risk (aRR 0.8, 95% CI 0.783-0.896). Participants discontinued PrEP because of medical and pharmacological challenges; perceived negative social norms and societal pressures; perceived undesirable pill characteristics and dosing schedules; low self-assessed HIV risk; perceived low benefit of PrEP; and low self-efficacy in adhering to PrEP. Our findings highlight the need for a multi-component intervention to promote PrEP retention.