Pre-exposure prophylaxis (PrEP) was implemented in Brazil in 2017 as an additional tool for combined HIV prevention. Individuals eligible for PrEP are at increased risk for other vaccine-preventable sexually transmitted infections, such as hepatitis A, hepatitis B, and human papillomavirus (HPV). In this context, regular PrEP follow-up visits represent a strategic opportunity not only for clinical monitoring but also for health education and immunization updates, contributing to the integrated prevention of these conditions. This study evaluated adherence to recommended vaccines against hepatitis A, hepatitis B, and HPV among PrEP users attending a tertiary care outpatient clinic in Paraná, Brazil.

Observational, longitudinal, and prospective study conducted between March 2023 and March 2025.

Of the 98 PrEP users included, 90 had vaccination records available. Regarding hepatitis A, 31 (31.6%) were already IgG-reactive for HAV at baseline. Among the 59 nonimmune individuals, 25 (42.4%) received at least one vaccine dose during follow-up, but only four completed the two-dose schedule. No natural seroconversions or hepatitis A cases were detected during the study period. For hepatitis B, 62 patients (63.3%) were immune, confirmed by anti-HBs levels > 10 mIU/mL, with two showing positive anti-HBc total results. Of the 32 susceptible individuals, 23 (71.9%) initiated the vaccination series, of whom 12 completed all three doses. Ten of these 23 (43.5%) underwent post-vaccination serology, and seven achieved seroconversion. Regarding HPV, seven patients (7.1%) had already completed the vaccination series before follow-up, and three (3.1%) had received two doses only. Among the nonimmunized, 33 (33.7%) began vaccination with at least one dose, and seven completed the series during follow-up. Forty-two (42.9%) did not receive any dose despite medical recommendations.

PrEP outpatient follow-up represents a strategic opportunity to promote immunization; however, despite multiple encounters with healthcare professionals, a significant proportion of users remained unvaccinated. New approaches are needed to increase vaccination coverage and reduce this population’s vulnerability to other STIs.