Newly Diagnosed Individuals in Molecular HIV-1 Clusters in Rhode Island over Three Decades.

Background: Characterizing clustering rates of people with HIV in high-risk populations can offer insights on the HIV epidemic, enhancing efforts to control its spread.

Methods: We investigated longitudinal dynamics of clustering rates among individuals newly diagnosed with HIV-1. Data were extracted from medical records of all people with HIV in Rhode Island with available viral sequences. Partial pol sequences were grouped by HIV diagnosis year, and clusters were identified in annual phylogenies. Clustering trends were estimated within eleven socio-demographic variables using the Mann-Kendall statistic. Associations with clustering propensity and changes over time were tested using generalized linear mixed-effects models.

Results: HIV-1 sequences from 2,630 individuals representing the statewide epidemic were analyzed across 33 annual datasets (1991-2023). Over this period, a continuous increase in clustering rates among newly diagnosed individuals was observed despite decreasing diagnoses over the last decade. Significant clustering upward trends were seen among newly diagnosed men who have sex with men, males, the 21-40 age group, non-Hispanic or Latino individuals, Whites, individuals with subtype B, and USA-born individuals, but not among individuals who inject drugs, females, and incarcerated individuals. Analyses of relative associations between groups within variables further corroborated these results.

Conclusions: Analyses focusing on molecular HIV clusters among newly diagnosed individuals in a statewide epidemic over three decades revealed significant evolving trends among those at highest risk of HIV transmission, patterns not seen in the overall population. These findings inform the design and development of targeted public health interventions aimed at high-risk populations to curb HIV spread.