Social network isolation and cohesion and their association with HIV clustering among Black and Latino sexual minority men: implications for public health strategy.

Evidence shows social networks shape HIV transmission by influencing partner access, behaviors, and health. Molecular cluster analysis offers insight into recent transmission, yet little is known about how network isolation or cohesion relate to clustering. This study examined social networks to identify factors associated with molecular HIV clustering. Data are from a cross-sectional study among Black and Latinx sexual minority men collected 2022-24 in Raleigh-Durham, NC. Participants nominated up to 20 friends and 20 sex partners. Other survey measures included age, gender, and socioeconomic status. Dyadic homophily was calculated using Jaccard similarity for race, STI status, drug use, and ethnicity. Network measures included the number of alters and a constraint score reflecting embeddedness. Molecular clusters were identified using pol sequences and nextHIV2. Ordinal logistic regression assessed associations with HIV status and cluster membership, adjusting for covariates. Among 100 participants (387 contacts), 60% were HIV-negative, 18% were people living with HIV (PWH) not in clusters, and 22% were PWH in clusters. Contact networks were sparse. Older age and more contacts were associated with cluster membership. Racial homophily increased odds of clustering, whereas larger networks, lower constraint, and greater STI negative status similarity reduced odds. Findings indicate that homophily and network structure are associated with HIV clustering and may inform HIV prevention strategies.