Very High HIV Incidence and Associated Risk Factors in a Longitudinal Cohort Study of Diverse Adolescent and Young Adult Men Who Have Sex with Men and Transgender Women.

To report HIV incidence and associated factors among young men who have sex with men (YMSM) and transgender women (TW). Data were collected February 2015 to July 2018 in the RADAR longitudinal cohort study of YMSM/TW aged 16–29 years (N = 1093). Data included tests for HIV and rectal STIs and self-reported sexual behaviors and networks characteristics. HIV incidence rates were 2.91 per 100 person years (44 seroconversions among 1513 person years). Incidence was significantly higher in Black participants than white (IRR 8.81; 95% CI 2.72–45.26) and Latinx (IRR 3.15; 1.49–7.28) participants, but no significant differences by gender identity were found. Testing positive for rectal STIs (HR 2.50; 95% CI 1.27–4.92) and sex with a partner from a high HIV incidence community area (HR 2.46; 95% CI 1.19–5.07) were associated with higher incidence. HIV incidence was very high and Black YMSM/TW experienced higher HIV incidence attributable to partner race and geographic residence. Rectal STIs were associated with increased HIV incidence.