The goal of this Hybrid Type I effectiveness-implementation trial is to test an evidence-based, flexible, and tailored intervention that leverages existing social network members to promote retention in care and viral suppression among people living with HIV aged 18-49.

This study is a Hybrid Type I effectiveness-implementation trial of an evidence-based, flexible, and tailored intervention that leverages existing social network members to promote retention in care and viral suppression. The study will be conducted in Chicago, Illinois and Alabama, two high burden priority areas in the National Ending the HIV Epidemic Plan. Both retention in care and viral suppression are critical targets in ongoing efforts to eliminate HIV, as persons adherent to antiretrovirals are unlikely to transmit HIV, and retention in care allows for ongoing monitoring of viral load and the delivery of other important services, e.g., case management, mental health, and substance use treatment.

Most clinic-based strategies to improve Continuum of Care outcomes focus on newly created network members, e.g., support groups, peer navigators, or case managers. In contrast, we identify and activate organic Support Confidants (SC)-those people who can offer the types of social support that can help to navigate life's complexities, including the stressors of living with HIV. The intervention uses sociograms, highly engaging social network diagrams, to identify an ideally positioned Support Confidant. Once a Support Confidant is identified, the Index and their Support Confidant attend a single session, in-person intervention with a trained interventionist. The intervention uses the Information Motivation Behavioral Skills Model, Motivational Interviewing, and Cognitive Behavioral Theory to promote Continuum of Care-specific support in the Index-Support Confidant relationship.

This study will conduct a Hybrid Type I randomized controlled trial with N=600 participants living with HIV, who will be randomized to receive the intervention (n=300) or treatment as usual (n=300). In addition, 300 Support Confidants also will be enrolled. At 12-months post-intervention, we will re-randomize dyads to continue receiving mini-boosters (n=150) or return to treatment as usual (n=150). Data collection at baseline, 12, and 18 months will include surveys and electronic medical record (EMR) data. The study will be implemented in community-based clinics and academic-affiliated health centers in Chicago and in Birmingham and Huntsville, Alabama. To study implementation in each setting and geographic context, we will use the Consolidated Framework for Implementation Research as the determinant framework and Reach, Effectiveness, Adoption, Implementation, and Maintenance as the evaluation framework. The specific aims of the study 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 6 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.

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.

If effective, the intervention has the potential to reduce HIV incidence by harnessing existing social support in the lives of people living with HIV, strengthening the public health impact of Treatment as Prevention. Thus, the research holds significant promise for addressing racial and geographic health disparities and will result in a sustainable, scalable program and implementation strategy that can be disseminated in HIV clinics nationwide.

Inclusion Criteria for Index Participants:

• Aged 18-49 years old, inclusive
• Speak English
• Own a cell phone not shared with anyone else
• Have missed at least one HIV care scheduled visit or have not been virally suppressed in the past 24 months.
• Resides in Chicagoland, Illinois or Alabama

Exclusion Criteria for Index Men:

• If a participant fails to meet all inclusion criteria

Inclusion Criteria for Support Confidants:

• Index agrees to engage the Support Confidant
• Age 18 years or older
• Speaks English
• Owns a cell phone not shared with others
• Is not a romantic/sexual partner of the Index participant

Exclusion Criteria:

• Romantic/Sexual partners of Index participant
• Relationship strain or abuse present in Index-Support Confidant relationship

Individual Participant Data (IPD) will not be available to researchers outside of the study team.

Due to the nature of the intervention, it is not possible to blind participants, interventionists, and investigators. However, we take the following steps to minimize bias, assess contamination, and enhance rigor: (1) collecting baseline data prior to randomization; (2) Treatment as Usual (TAU) providers are blinded to allocation; and (3) assessing contamination at follow-up surveys by identifying overlap between the networks of those in each study arm.