Low Incidence and Prevalence of Hepatitis C Virus Infection Among Sexually Active Non-Intravenous Drug-Using Adults, San Francisco, 1997–2000

BACKGROUND: The rate of sexual transmission of hepatitis C virus (HCV) is debated. GOAL: The goal was to measure the risk of sexual transmission of hepatitis C virus (HCV) in a sexually active population. STUDY DESIGN: Sexual behaviors and HCV antibody status were measured in persons seeking repeat HIV testing in San Francisco from October 1997 through March 2000. RESULTS: Among 981 repeat testers, the prevalence of HCV antibody was 2.5%. Among men who have sex with men who denied intravenous drug use (n=746), factors associated with HCV antibody positivity include age greater than 50 years (odds ratio [OR], 8.5; 95% confidence interval [CI], 2.6-27.7), HIV infection (OR, 5.7; 95% CI, 1.6-20.6), and being nonwhite (OR, 3.3; 95% CI, 1.1-10.0). HCV antibody positivity was not associated with sexual risk behaviors. In 576.6 person-years of observation, no new HCV seroconversions occurred (incidence=0 per 100 person-year; 95% CI, 0-.6), whereas 6 new herpes simplex virus-2 infections (2.8 per 100 person-years) and 10 new HIV infections (1.8 per 100 person-years) occurred. CONCLUSION: The absence of new HCV infections in this sample supports the hypothesis that the risk of sexual transmission of HCV is low.