PROJECT SUMMARY HIV remains the leading cause of death among adults in South Africa despite the availability of antiretroviral therapy (ART) due to failure to initiate ART and failure to remain on ART. Gaps in HIV care are especially prominent among key populations at high risk for both HIV and reduced use of HIV services. One population with an HIV prevalence double the age and sex-matched general population (23%) and with low engagement in HIV care is individuals recently released from incarceration. During incarceration >90% initiate ART; following reentry into the community only 34% remain in care. The transition from the controlled carceral environment and its restricted autonomy to life in the community requires reestablishing planning skills, self- efficacy, and social support and overcoming bureaucratic barriers to accessing community clinics. We have demonstrated that an intervention that circumvents clinic barriers by directly providing ART and builds behavioral skills through peer-facilitator led group sessions improves care continuity following release from incarceration. In a pilot study of this intervention supported by NIMH, termed SPARCS, among 176 participants, 36% of those in the care as usual compared to 61% of those in the intervention arm were in-care 6 months after corrections release. These results raise important questions regarding possibility of programmatic scale-up. Scale-up requires achieving a balance between effectiveness, feasibility, and cost. Notably, the tension between effectiveness and feasibility may require reducing overall effectiveness – such as by eliminating a component of SPARCS – to increase feasibility. To explore each of these questions, we are proposing a hybrid type I effectiveness-implementation study structed with the RE-AIM framework (Reach, Effectiveness, Adoption, Implementation, Maintenance). First, we are proposing a 2x2 factorial design to maximize power of a randomized controlled trial of the Full-SPARCS intervention and the two distinct components termed “ART-SPARCS” and “Group-SPARCS” and usual care, to test for a difference in viral load suppression 6 months from correctional facility release. Second, we propose characterize implementation in terms of reach, adoption or adoption potential, acceptability, and fidelity. Finally, will use findings from the RCT to inform costing and cost-effectiveness to inform policy makers regarding cost of SPARCS and components and cost-effectiveness of each component and the full SPARCS to inform implementation cost and potential long-term sustainability or maintenance. This project has the potential to generate considerable new knowledge on interventions that can improve care continuity for this population and key findings for potential scale-up relevant to policy makers. This proposed study has the potential to generate actionable knowledge to improve outcomes for community reentrants and contribute to overall goals of HIV epidemic control.