Harnessing social network support to improve retention in care and viral suppression among people living with HIV in Chicago and Alabama: A hybrid type I effectiveness-implementation trial - We will conduct a Hybrid Type I effectiveness-implementation randomized controlled trial of an evidence-based, flexible, and tailored intervention that harnesses social support to promote retention in care and viral suppression among people living with HIV aged 18-49. The study will take place in Cook County (Chicago, Illinois) and Alabama, two high-burden areas prioritized in the national Ending the HIV Epidemic Plan. Existing efforts to improve Continuum of Care outcomes for people living with HIV often rely on newly created network members, e.g., peer navigators, support groups, case managers. Often missing from these approaches is a focused attempt to harness organic social network supports, i.e., those people who already offer critical forms of emotional, informational, and instrumental support. In contrast, the intervention was developed to identify, activate, and harness organic social network support for people living with HIV. The intervention uses (1) social network visualization and theory to help men identify a support confidant to engage in care; (2) the Information-Motivation-Behavioral Skills Model targeted at the support confidant to activate and maintain dyadic social support; (3) a linked social support model to target the drivers of retention in care and viral suppression. Content is delivered via a single face-to-face session and mini-boosters. The intervention’s flexibility ensures that support confidants are selected based on their supportive function rather than their role. In a pilot randomized controlled trial in Chicago, we demonstrated feasibility, acceptability, and efficacy. To now test effectiveness, N=600 people living with HIV in Chicago and Alabama will be randomized to receive the intervention (n=300) or treatment as usual (n=300). We also will enroll 300 support confidants. At 12-month post-intervention, we will re-randomize dyads to continue receiving quarterly mini-boosters (sustained support: n=150) or return to treatment as usual (n=150). Data collection at baseline, 12 months, and 18 months will include surveys and electronic medical record data. To study implementation, we will use the Consolidated Framework for Implementation Research as the determinants framework and Reach, Evaluation, Adoption, Implementation, and Maintenance framework as the evaluation framework. The specific aims are to: (Aim 1) Evaluate the (a) effectiveness of a social support intervention versus treatment as usual over 12 months with 600 people living with HIV ages 18-49 and (b) value of continuing to offer social support over another 12 months. The primary outcomes are retention in care and Viral Suppression, as measured by electronic medical record data on missed visit proportion and viral load; (Aim 2) Examine if intervention effects (a) vary between Chicago and Alabama, (b) are mediated by changes in the Index’s level of motivational readiness, self-efficacy, and stigma expectancies, and (c) are moderated by mental health and substance use at the Index level; and (Aim 3) Evaluate the implementation of the intervention using the Consolidated Framework for Implementation Research and the Reach, Evaluation, Adoption, Implementation and Maintenance frameworks. We will conduct surveys and focus groups with key stakeholders to assess the inner and outer settings, implementer and intervention characteristics, and multi-level process factors within the Consolidated Framework for Implementation Research. We will assess the following implementation outcomes for the study in each clinical setting and geographic context: Reach, Adoption, Implementation, and Maintenance.