Abstract Body

PrEP discontinuation is a challenge for PrEP programs as HIV seroconversion usually occurs in these stopping periods. Several studies with adult men who have sex with men (MSM) and transgender women (TGW) have been published, but it is still scarce for adolescent MSM and TGW. Therefore, this study aims to analyze factors associated with PrEP discontinuation.

PrEP1519 is the first PrEP demonstration cohort study in Latin America among MSM and TGW aged 15-19 years. It takes place in 3 large Brazilian capital cities. We included individuals enrolled in PrEP from February 2019-September 2021. PrEP discontinuation was defined as no possession of PrEP pills for more than 90 days. Participants who seroconverted or possessed PrEP were right-censored. Probabilities of non-discontinuation were estimated using Kaplan Meier. The survival distributions defined by covariates were compared using log-rank and Wilcoxon tests. Cox regression models were carried out, and adjusted hazard ratios (aHR) with 95% confidence interval were estimated.

A total of 1146 participants started PrEP, 22% were 15-17 yo. Most were MSM (91.5%), self-identified as black/brown (70.4%). Over the study period, 53.4% were persistent users and almost half discontinued PrEP (46.6%). The probability of discontinuation within the first 12 weeks was 20.1%, and the median time to PrEP discontinuation was 168 days. Multivariate analysis showed that risk of discontinuation increased 64% in TGW (aHR: 1.64; CI: 1.24 – 2.18) when compared to MSM; and increased 68% (aHR: 1.68; CI: 1.31 – 2.15) and 31% (aHR: 1.31; CI: 1.03 – 1.66) if the risk perception for HIV was low or medium, respectively, when compared with those with high-risk perception. Having an HIV-positive partner in the past 3 months was associated with a lower risk of discontinuation (aHR: 0.58; CI: 0.36 – 0.93). Socioeconomic characteristics, housing situation and other sexual behaviors were not associated with discontinuation.

Adolescents’ behaviors are dynamic and fluid; therefore, we must continually adapt to their context and respect their choices. The greater social vulnerability may have increased the risk of discontinuation in TGW. PrEP discontinuation at an early stage was associated with a disconnection between risk perception and sexual behavior. It is important to emphasize the value of PrEP as an HIV prevention tool, especially for adolescents with medium and low-risk perceptions for HIV infection, and for TGW.