Hepatitis C antibody prevalence and active hepatitis C infection in HIV-negative gay, bisexual, and other men who have sex with men in Barcelona and Madrid, Spain (March 2018-March 2021)

Objectives: Hepatitis C virus (HCV) has been recognized as a sexually transmitted infection (STI) in HIV-positive men who have sex with men (MSM), with an increased notification in HIV-negative MSM. The aim of this study was to determine the prevalence of HCV antibody and active HCV infection in HIV-negative gay, bisexual, and other MSM (GBMSM), and their characteristics, in Barcelona and Madrid, from March 2018 to March 2021.Methods: Cross-sectional study conducted on 3548 HIV-undiagnosed GBMSM, across four HIV/STI testing centers. Respondents submitted an online, self-administered questionnaire after consultation, which collected information on sociodemographics, sexual health history, HCV knowledge, and substance consumption. Prevalence of HCV antibodies was determined by a reactive result in a rapid anti-HCV test or enzyme-linked immunosorbent assay (ELISA), while active HCV infection was determined by participants who were also positive on an HCV-RNA test. Crude and adjusted Poisson analyses with robust variance are presented for both prevalence and active infection.Results: In total, 97.6% of participants (n = 3463) were HIV-negative. Of those, 18 were found to have HCV antibodies (0.52%), of which nine (0.26%) were also HCV-RNA positive. Those with HCV antibodies were associated to have lived with an HCV ( + ) person (adjusted prevalence ratio [APR]: 7.84, [95% confidence interval: 2.50-24.53]), using injectable drugs for sex (APR: 6.92, [1.20-39.79]) and testing positive for an STI in the previ-ous year (APR: 4.06, [1.09-15.12]). Presenting an active infection was strongly associated with a previous HCV diagnosis (APR: 100.82 [22.16-458.76]), sexualized injectable drug use (APR: 17.53 [2.70-113.76]), and sharing douching material (APR: 7.45, [2.12-25.95]).Conclusion: Sexual practices with a higher risk of bleeding and sexualized drug use, particularly sexualized injectable drug use, were associated with higher rates of HCV diagnosis in GBMSM. Identifying these practices during consultation, contact tracing new cases and regularly testing those with a previous history of HCV, will facilitate HCV eradication.