HIV pre-exposure prophylaxis (PrEP) is an effective prevention strategy, available in the SUS since 2018 for priority populations, such as men who have sex with men (MSM). Recent hepatitis A outbreaks have emerged, predominantly among MSM, associated with specific sexual practices. This study aimed to determine the prevalence of individuals susceptible to hepatitis A virus (HAV) among PrEP users and to identify factors associated with susceptibility.

A cross-sectional, retrospective, descriptive and analytical study examined electronic medical records of 352 PrEP users followed in outpatient care between 01/01/2022 and 12/31/2024 at a university hospital in the Federal District (DF). Sociodemographic, behavioral, clinical data and laboratory test results were collected, including anti-HAV IgG. Poisson regression with robust variance was used to estimate prevalence ratios and adjusted prevalence ratios with their respective 95% confidence intervals (95% CI) for factors associated with susceptibility to HAV infection. In the multivariate analysis, the stepwise forward method was used.

The representative profile of the study population was characterized as brown man (46%), median age 33 years, born in the DF (49%), cisgender (94%), homosexual (80%), with high educational level (72.5% ≥12 years of schooling). The results revealed that 48.1% of the sample were susceptible to hepatitis A. Multivariate analysis identified as a risk factor for susceptibility to hepatitis A being under 30 years of age (PR: 1.5 [95% CI 1.1‒2.1] p<0.02).

The high prevalence of susceptibility among young PrEP users, especially MSM, highlights the urgency of implementing public health campaigns informing about the risks of HAV infection in this population and the importance of immunization. It is important to highlight that the seropositivity rate found (51.9%) observed is considerably below the vaccine coverage or population immunity needed to prevent hepatitis A outbreaks, estimated between 70% and 80%*. This study provides evidence supporting the integration of hepatitis A vaccination into combined prevention strategies for PrEP users, an action implemented by the Ministry of Health starting in May 2025.