Prevalent and incident hepatitis C virus infections among participants in a pre-exposure prophylaxis program in Taiwan.

To better understand the burden of hepatitis C virus (HCV) infection among HIV-negative men who have sex with men (MSM) in Taiwan, we conducted a prospective surveillance study of HCV viremia and bacterial sexually transmitted infections (STIs) among users of pre-exposure prophylaxis (PrEP) for HIV. Between 2018 and 2024, a total of 603 individuals participated in the national PrEP program. The baseline HCV seroprevalence was 1.2%, and no incident cases of HCV viremia were observed among the 364 participants enrolled in this surveillance study with 311.58 person-years of follow-up, giving the upper limit of the 95% confidence interval estimated to be 0.96 per 100 person-years. In contrast, 69 episodes of bacterial STIs were recorded, corresponding to an incidence rate of 22.14 per 100 person-years, indicating ongoing high-risk sexual behaviors in this population. These findings underscore the need for continued surveillance and strengthened prevention strategies to advancing efforts toward HCV elimination.