Effect of Implementation Strategies on Pre-Exposure Prophylaxis Persistence among Female Sex Workers in South Africa: an Interrupted Time Series Study.

Background A disproportionate number of new HIV infections in South Africa are among female sex workers; pre-exposure prophylaxis (PrEP) for HIV prevention is freely available to female sex workers in the country, but unique barriers challenge PrEP persistence. TB HIV Care, a large South African non-profit organisation that provides daily oral PrEP (tenofovir disoproxil fumarate and emtricitabine), has implemented multiple strategies to improve PrEP persistence. We aimed to evaluate the effect of different implementation strategies on PrEP persistence in a large-scale real-world setting.Methods In this interrupted time series study, we estimated level changes in 1-month oral PrEP persistence associated with roll-out of various implementation strategies among female sex workers across nine districts in South Africa. We used routinely collected data from TB HIV Care programme files from June 7, 2016, to April 30, 2021. Poisson regression of 1-month persistence was used to assess the effect of these strategies. In secondary analyses, we tested the association between each of the strategies and 4-month persistence. Findings The median 1-month PrEP persistence for female sex workers was 33% (IQR 27-40). SMS support and refill reminders were associated with an 11% relative increase in 1-month persistence (risk ratio [RR] 1 center dot 11, 95% CI 1 center dot 02-1 center dot 26) and clinical mentoring for PrEP providers was associated with a 127% relative increase (RR 2 center dot 27, 95% CI 1 center dot 94-2 center dot 66) among female sex workers. The loyalty rewards programme was negatively associated with 1-month persistence (RR 0 center dot 71, 95% CI 0 center dot 67-0 center dot 83). Although clinical mentoring improved 4-month persistence, SMS support text messages had no significant effect.Interpretation Identification and subsequent use of clinical mentoring for PrEP providers and SMS support and refill reminders might improve the usefulness of PrEP overall to prevent new HIV infections among female sex workers. PrEP persistence remains an important issue, and strategies to build on our findings are needed.