The Community PrEP Study: a randomized control trial leveraging community-based platforms to improve access and adherence to pre-exposure prophylaxis to prevent HIV among adolescent girls and young women in South Africa-study protocol.

<bold>Background: </bold>HIV incidence among South African adolescent girls and young women (AGYW) remains high, but could be reduced by highly effective pre-exposure prophylaxis (PrEP). Unfortunately, AGYW report significant barriers to clinic-based sexual and reproductive health services. Even when AGYW access PrEP as an HIV prevention method, poor prevention-effective use was a serious barrier to achieving its optimal HIV prevention benefits. Determining the acceptability and feasibility of community-based platforms to increase AGYW's access to PrEP, and evaluating behavioural interventions to improve prevention-effective use of PrEP are needed.<bold>Methods: </bold>We propose a mixed-methods study among AGYW aged 16-25 years in Eastern Cape Province, South Africa. In the first component, a cross-sectional study will assess the acceptability and feasibility of leveraging community-based HIV counselling and testing (CBCT) platforms to refer HIV-negative, at-risk AGYW to non-clinic-based, same-day PrEP initiation services. In the second component, we will enrol 480 AGYW initiating PrEP via our CBCT platforms into a three-armed (1:1:1) randomized control trial (RCT) that will evaluate the effectiveness of adherence support interventions to improve the prevention-effective use of PrEP. Adherence will be measured over 24 months via tenofovir-diphosphate blood concentration levels. Qualitative investigations will explore participant, staff, and community experiences associated with community-based PrEP services, adherence support activities, study implementation, and community awareness. Costs and scalability of service platforms and interventions will be evaluated.<bold>Discussion: </bold>This will be the first study to assess the acceptability and feasibility of leveraging CBCT platforms to identify and refer at-risk AGYW to community-based, same-day PrEP initiation services. It will also provide quantitative and qualitative results to inform adherence support activities and services that promote the prevention-effective use of PrEP among AGYW. By applying principles of implementation science, behavioural science, and health economics research, we aim to inform strategies to improve access to and prevention-effective use of PrEP by AGYW.<bold>Trial Registration: </bold>ClinicalTrials.gov NCT03977181 . Registered on 6 June 2019-retrospectively registered. [ABSTRACT FROM AUTHOR]