Project Summary: Significance: South Africa has the highest number of adolescents living with HIV in the world with KwaZulu-Natal the epicenter, yet adolescents are poorly prepared for transition from pediatric to adult services as evidenced by poor retention in care and viral suppression after transition. In-person and mHealth adolescent-friendly interventions have potential to remedy the disparities for adolescents living with HIV in low to middle income countries but larger, powered randomized trials are needed. Differentiated care: Transition readiness assessments can be used to identify the more vulnerable adolescents and focus resources on adolescents who would benefit most from additional interventions. Innovation: This study is the first study to evaluate interventions to support transition from pediatric to adult care for adolescents living with HIV in sub- Saharan Africa. mHealth has not previously been used to address the critical transition period for adolescents living with HIV. We hypothesize that in-person or mHealth adolescent-friendly interventions will improve viral suppression for adolescents living with HIV with low to intermediate transition readiness as they transition to adult care. We also hypothesize that mHealth interventions can provide equal benefits to in-person interventions with lower costs, broader reach, and easier adoption. Approach: Using a Type I hybrid effectiveness- implementation design, we will evaluate the effectiveness of in-person or mHealth delivered adolescent-friendly transition interventions for adolescents living with HIV with low to intermediate transition readiness. Using a stepped-wedge, delayed implementation randomized clinical trial design we will measure the effectiveness of the interventions compared to standard of care on viral suppression and retention in care (Aim 1). Simultaneously, we will use the RE-AIM framework to measure the implementation factors associated with the implementation strategies of peer educators as clinic champions and audit and feedback (Aim 2). We will also determine if the interventions lead to changes in transition readiness scores and their underlying domains for future targeted interventions further differentiating care based on transition readiness (Aim 3). Investigators: Multiple Principal Investigators: Brian Zanoni has been working in adolescent HIV in South Africa since 2006, has received NIH funding through an R21 to develop the transition readiness assessment and K23 to develop and pilot the mHealth intervention used in this proposal. Monerndran Archary is an expert in pediatric and adolescent HIV in South Africa. He and Dr. Zanoni have been working together since 2011 in developing transition readiness assessments and interventions to improve adolescent transition care. Co-investigators: Maryam Shahmanesh is an expert in clinical trials among youth in rural KwaZulu-Natal, South Africa. Jessica Haberer is an expert in the development and implementation of...