Same-Day Initiation of Oral Pre-Exposure Prophylaxis is High Among Adolescent Men Who Have Sex With Men and Transgender Women in Brazil.

PURPOSE: This study analyzed the sociodemographic and behavioral characteristics of adolescent men who have sex with men (aMSM) and transgender women (aTGW) initiating oral pre-exposure prophylaxis (PrEP) in human immunodeficiency virus (HIV) prevention clinics. METHODS: PrEP1519 is a prospective, multicenter, open-label PrEP demonstration cohort study of aMSM and aTGW aged 15-19 years living in three large Brazilian capital cities. For this analysis, we included adolescents who enrolled in PrEP1519 from February 2019 to August 2021. Adolescents who visited PrEP clinics were classified into four groups based on PrEP eligibility and on their decision to use PrEP: (1) ineligible for same-day PrEP initiation; (2) eligible for same-day PrEP initiation, initiated PrEP at first visit; (3) eligible for PrEP initiation, initiated PrEP after the first visit; and (4) eligible for same-day PrEP initiation but declined. The groups that were eligible for same-day PrEP initiation were compared using the Chi-square and Fisher's exact tests. RESULTS: Of the 1,254 adolescents enrolled in the PrEP1519 study, 61 (4.9%) were considered ineligible for same-day PrEP initiation. Of the 1,193 eligible for same-day PrEP initiation, 1,113 (93.3%) initiated PrEP [1,054 initiated PrEP in the first visit (88.3%) and 59 in subsequent visits (4.9%)] and 80 (6.7%) did not. Despite 90% of the PrEP decliners reporting a low risk of HIV infection, most reported condomless anal sex in the past six months (70%). DISCUSSION: Same-day PrEP initiation among aMSM and aTGW was high, highlighting that this strategy was important to promote PrEP initiation among adolescents with increased vulnerability to HIV in Brazil.