Effect of tenofovir-based HIV pre-exposure prophylaxis against HBV infection in men who have sex with men

Abstract

Background and Aims: Men who have sex with men (MSM) are vulnerable to contracting HBV as a sexually transmitted infection. We evaluated the incidence of HBV infection (HBI) and the prophylactic effect of tenofovir-based pre-exposure prophylaxis (PrEP) on HBI in an MSM cohort. Methods and Results: MSM who were older than 16 years were enrolled from January 2018 and followed up until June 2021 and tested for HIV, bacterial sexually transmitted infections, and HBsAg/ HBsAb and HBcAb every 3 months based on inclusion criteria, including HBsAg, HBcAb, HBsAb, and HIV negativity at enrollment. HBI was defined as seroconversion of HBsAg or HBcAb status. The log-rank test was used to evaluate the prophylactic effect of PrEP against HBI. As a substudy, individuals excluded from the main study due to HBs Ab positivity were evaluated for HBI incidence. Among 1577 MSM, 786 participants (546 PrEP nonusers, 131 daily PrEP users, and 109 event-driven PrEP users) met the criteria and were included. The annual incidence of HBV among PrEP nonusers (3.8%, 21 infections, with 559.5 person-years) was significantly higher (p = 0.018, log-rank test) than that among daily PrEP users [0.77%, 1 infection (admitted nonadherence), with 129.3 person-years] and event-driven PrEP users (no infection with 93.8 person-years). Although the incidence of HBI and HIV infection decreased with PrEP use, the incidence of other sexually transmitted infections was higher in both daily and event-driven PrEP users. The annual incidence of HBV among HBsAb-positive and HBcAb-negative PrEP nonusers was 1.8% (3 infections, with 167.5 person-years). Conclusions: Tenofovir-based PrEP prevented HBI among MSM in a real-world setting.