PROJECT SUMMARY Background. To meet the UNAIDS 95-95-95 Fast Track targets for HIV epidemic control by 2030, strategies that support people living with HIV (PLHIV) to achieve and maintain viral suppression must be prioritized. Rapid scale-up of antiretroviral therapy (ART) through Universal Test and Treat policies has improved HIV treatment outcomes at population level, but heterogeneities in the HIV epidemic and response have yielded disparities in viral load outcomes. Examining longitudinal viral load outcomes, and the multilevel factors shaping them, is vital for geographic prioritization and differentiation of HIV services to distinct groups of PLHIV. Study Goal and Aims. The goal of this study is to assess patterns, predictors, and mechanisms underpinning longitudinal viral load outcomes (or trajectories) among PLHIV in Rakai, Uganda. The specific aims of this study are to: 1) Identify household and community-level predictors of virologic failure and durable viral suppression among PLHIV at population level; 2) Examine health facility characteristics associated with virologic failure at facility level; and 3) Explore the mechanisms through which social, contextual, and health systems factors influence viral load outcomes. The proposed research aligns with NIMH Division of AIDS Research priorities to advance design of interventions, delivered beyond the individual level, prolonging engagement in HIV care. Approach. This explanatory, sequential mixed-methods study will leverage the data and infrastructure of the Rakai Community Cohort Study (RCCS), an open, population-based cohort study of individuals aged 15-49 years residing in 40 communities in Rakai, Uganda. Aim 1 is a secondary data analysis testing whether fishing community residence, higher community-level migration, and lower household wealth are associated with increased risk of virologic failure over five years of follow-up. Aim 2 will integrate RCCS data with programmatic metadata from 161 health facilities to cross-sectionally identify compositional correlates of virologic failure in each facility’s patient population. Building on findings from Aims 1-2, Aim 3 will involve primary qualitative data collection through in-depth interviews with 20-24 PLHIV and 10-12 HIV clinicians. Interviews will explore synergies in multilevel factors identified in Aims 1-2 and how they shape PLHIV’s viral load outcomes over time. Findings from Aims 1-3 will be triangulated to enrich scientific inquiry into salient HIV treatment gaps. Fellowship Information. The proposed research will serve as the doctoral dissertation of Mr. Joseph Rosen, a PhD student at the Johns Hopkins Bloomberg School of Public Health. The training is guided by one Primary Sponsor, three Co-Sponsors, and one Scientific Advisor with complementary methodological and topical expertise, including care and treatment outcomes research with PLHIV in Rakai, Uganda. The training plan will prepare Mr. Rosen to become a leading independen...