PrEP reinitiation, uptake, and persistence as targets for reducing HIV incidence and racial and ethnic inequities among men who have sex with men in Boston, USA: a network modeling study.

Abstract

A decade of pre-exposure prophylaxis (PrEP) has lowered HIV incidence among men who have sex with men (MSM) but not enough to meet Ending the HIV Epidemic goals, and racial and ethnic disparities persist. The PrEP era has produced a population of former users facing lower barriers to restarting than PrEP-naive individuals. Reinitiation has not been treated as a distinct target. We aimed to compare its population-level impact with that of uptake and persistence. We used a network model of 100,000 cisgender MSM aged 15-65 in Boston, USA (21.5% Black, 18.9% Hispanic, 44.5% White, and 15.1% Other), parameterized with electronic health record data from 37,722 MSM (2012-2023) and calibrated to local surveillance. We compared 10-year population-wide and equity-focused (Black and Hispanic MSM) interventions scaling uptake, persistence, and reinitiation, reporting infections averted, number needed to treat (NNT), and disparities at comparison intensities, defined as multiples of the baseline reinitiation rate. A 2× reinitiation scale-up averted 15.8% of infections (1481; NNT 40) versus 10.0% for 2× uptake and 5.6% for maximum persistence; 5× reinitiation averted 32.6% at the same NNT. Equity-focused reinitiation produced the most favorable relative disparity patterns of the three levers, though inequities remained. Reinitiation was the most impactful PrEP continuum lever, a prevention-side analog of ART re-engagement warranting prospective evaluation. Restart can be supported with existing infrastructure, including EHR-triggered prompts at return encounters, and equity-focused implementation for Black and Hispanic MSM offers the most favorable disparity patterns. US National Institutes of Health and the Emory Center for AIDS Research.