PROJECT SUMMARY A combination of individual-, network-, community-, and structural-level variables impact all steps in the HIV Care Continuum, particularly in the Deep South states of Alabama (AL), Louisiana (LA), and Mississippi (MS), which disproportionately bear the nation's HIV burden while simultaneously having the fewest healthcare resources. While the individual-level correlates of viral suppression (VS) are well-known, few epidemiologic studies, especially those that are digitally-based, have examined VS from a multilevel lens that accounts for the role of geographic and community-level characteristics germane to the Deep South, such as aggregate poverty measures, racial segregation, and healthcare access. Epidemiological studies also typically exclude people with HIV (PWH) with non-sustained VS (non-VS) or without recent HIV labs, as these are among the hardest to identify and reach due to their limited healthcare involvement. Our highly experienced study team will address these research gaps through the proposed UG3-UH3 study, which will use mHealth technology to optimally recruit, screen, enroll, and retain a prospective digital cohort of 1000 PWH in AL, LA, and MS with non-VS or who otherwise lack evidence of having been in care for the previous 12 months, leveraging long-standing relationships with public health departments in each of these three states. We will assemble a community advisory board (CAB), consisting of PWH, health department partners, and HIV care team members in the three states and we will use the Information System Research (ISR) Framework to tailor features of an existing adherence management app for PWH, WiseApp. We will test usability of the Drive to Zero app prototype with PWH and informaticians. Eligible cohort participants will be PWH ages ≥18 years, living in AL, LA, or MS, living with HIV for ≥12 months, and entered in the Enhanced HIV/AIDS Reporting System (eHARS), a standardized document-based surveillance database used by all state health departments to report diagnosis and outcomes, with a recorded VL≥200 c/mL ≤12 months or have missing HIV lab values during that same period. Participants will be followed for three years with iterative annual psychosocial quantitative survey assessments conducted via the Drive to Zero app to assess predictors, mediators, and moderators for non-VS. We will contextualize quantitative data by using geospatial analysis, linking participant residence addresses at time of enrollment to Census tract data. Participants of the digital cohort (n=45) will also be eligible to participate in qualitative in-depth interviews to contextualize quantitative results. The findings from this study will inform efforts to recruit large, digital cohorts of PWH and will be among the first to demonstrate effective methods of retaining digital cohorts for HIV as well as other health conditions. Study findings will also help identify multilevel factors that contribute to non-VS in the Deep South, ...