PrEP Use and HIV Incidence Among Youth At-Risk for HIV Infection in Los Angeles and New Orleans: Findings From ATN 149

Supplemental Digital Content is Available in the Text. Introduction:Expanding HIV pre-exposure prophylaxis (PrEP) use is key to goals for lowering new HIV infections in the U.S. by 90% between 2022 and 2030. Unfortunately, youth aged 16-24 have the lowest PrEP use of any age group and the highest HIV incidence rates.Methods:To examine the relationship between HIV seroconversion and PrEP uptake, adherence, and continuity, we used survival analysis and multivariable logistic regression on data of 895 youth at-risk for HIV infection enrolled in Adolescent Trials Network for HIV Medicine protocol 149 in Los Angeles and New Orleans, assessed at 4-month intervals over 24 months.Results:The sample was diverse in race/ethnicity (40% Black, 28% Latine, 20% White). Most participants (79%) were cis-gender gay/bisexual male but also included 7% transgender female and 14% trans masculine and nonbinary youth. Self-reported weekly PrEP adherence was high (98%). Twenty-seven participants acquired HIV during the study. HIV incidence among PrEP users (3.12 per 100 person year [PY]) was higher than those who never used PrEP (2.53/100 PY). The seroconversion incidence was highest among PrEP users with discontinuous use (3.36/100 PY). If oral PrEP users were adherent using 2-monthly long-acting injectables, our estimate suggests 2.06 infections per 100 PY could be averted.Conclusions:Discontinuous use of PrEP may increase risk of HIV acquisition among youth at higher risk for HIV infection and indications for PrEP. Thus, to realize the promise of PrEP in reducing new HIV infections, reducing clinical burdens for PrEP continuation are warranted.