This is a Type I Hybrid effectiveness-implementation trial to evaluate an HIV Pre-Exposure Prophylaxis (PrEP) medication adherence, persistence and social support app (Vuka+) for adolescent girls and young women (AGYW) in South Africa. This 6-month, 2-arm effectiveness and implementation trial (standard of care [SOC] vs. intervention app) will assess acceptability, feasibility and effectiveness. In addition, we will gather information on intervention delivery and barriers and facilitators for real-world delivery to inform future implementation and scale up.

We will recruit 330 AGYW, aged 15-24 from the surrounding community, PrEP clinics and service providers in Cape Town, South Africa. If AGYW qualify for enrollment, they will be offered daily Truvada as PrEP. Participants will then be randomized 1:1 at baseline to SOC counselling and the Vuka+ intervention app or SOC counselling only (control). All participants will receive their regularly scheduled PrEP clinical care visits. At baseline, 1-, 3- and 6-month follow-up visits, participants will complete biobehavioral surveys, undergo HIV testing and pregnancy testing, and provide a urine (month 1 and 6) and DBS sample (months 1, 3 and 6) for tenofovir assessment. Intervention arm participants will also have the following study activities: install the intervention app on their phones at baseline study visit and be asked to use the intervention app for at least 5-10 minutes daily for 6 months. During this time, they will be prompted by the app to complete daily activities or health and wellness readings and to complete a weekly brief assessment related to their PrEP use. At follow-up study visits, intervention arm participants will complete an additional set of questions evaluating their app use experience and a subsample of participants will complete an in-depth qualitative exit interview to assess their app use experience, acceptability of the intervention and their evaluation of the app's content.

Inclusion Criteria:

• Assigned female at birth
• Age 15-24 years
• Healthy and weight at least 35kg
• Sexually active (had a male sexual partner in the past 6 months)
• Consistent access to a smartphone
• HIV-negative (clinic test)
• PrEP naive or no PrEP use in the past 6 months
• Eligible to start oral PrEP

Exclusion Criteria:

• Unable to currently start PrEP
• Abnormal laboratory, medical, physical, or social finding which could impact study participation, by investigator discretion
• Unwilling or unable to provide informed consent
• Participating in another PrEP trial
• Unwilling to provide at least 2 forms of contact for follow-up
• Taking renal toxic medications
• Sexual partner known to be HIV-positive