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.