HIV incidence and risk factors associated among adolescent's men who have sex with men and transgender women enrolled in a PrEP cohort study in Brazil


BACKGROUND: Adolescent men who have sex with men (aMSM) and transgender women (aTGW) are disproportionally affected by the HIV epidemic mainly due to structural and behavioral factors, and face barriers to accessing HIV prevention and care services. We aimed to analyze factors associated with incident HIV infection among aMSM and aTGW enrolled in PrEP.
METHODS: PrEP1519 is a single-arm, demonstration cohort study of daily TDF/FTC as PrEP among aMSM and aTGW aged 15-19 years old (yo). It is ongoing in three Brazilian capital cities. Eligible are those HIV uninfected at baseline, at high risk of HIV, and no risk of kidney and liver damage. We included those enrolled in PrEP, who had at least one PrEP dispensation and two visits at PrEP clinics, from February/2019-October/2021. Study visits occurred at baseline, weeks 4, 12, and then quarterly. Demographic and sociobehavioural data were collected by a questionnaire. Cox regression model was used to model the time to seroconversion of a PrEP user and to estimate adjusted hazard ratios (aHR) by medication possession ratio. Participants who had PrEP pills and an HIV-negative test were right-censored at the maximum follow-up date at 96 weeks.
RESULTS: During the follow-up, 1,043 adolescents were enrolled in PrEP. Most MSM (91.9%), 18-19 yo (80.8%), self-identified as black/brown (69.7%). HIV incidence rate was 1.7 (95%CI: 0.8-2.6) per 100 person-years. Self-reported sexually transmitted infections (aHR: 3.02; 95%CI: 1.06'8.56), PrEP initiation during thequarantine measures of theCOVID-19 pandemic (aHR: 3.89; 95%CI:1.13'13.4), commercial sex in the last 3 months (aHR: 3.47; 95%CI:1.14'10.58), and fewer years of schooling (aHR: 2.22; 95%CI:0.75'6.55) were predictors of the HIV incidence. The estimated incidence for TGW was lower than for aMSM (aHR:0.32; 95%CI:0.04'2.51), but 95%CI was wide and imprecise.Indicators of sexual practices were not associated with the incidence.
CONCLUSIONS: The estimated HIV incidence was lower when compared to adult MSM and TGW non-PrEP users in other Brazilian studies but higher compared to the rates in adults PrEP studies, which indicates more attention to adolescents in PrEP programs is needed.

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