Sexual transmission of hepatitis C virus among patients attending sexually transmitted diseases clinics in Baltimore--an analysis of 309 sex partnerships.

The prevalence of antibodies to hepatitis C virus (anti-HCV), the behavioral and laboratory-derived risk factors for anti-HCV, and the quantity and homology of HCV RNA were assessed among 1039 non-injection drug-using sexually transmitted disease (STD) patients representing 309 sex partnerships. Thirty-seven (7%) of 555 males and 19 (4%) of 484 females had anti-HCV. In logistic regression analyses, factors associated with anti-HCV included age (P < .001), greater numbers of lifetime sex partners (P = .023), human immunodeficiency virus infection (P < .001), Trichomonas infection (P < .001), cigarette smoking (P < .001), and male homosexual exposure (P = .012). Among couples, females whose sex partners were anti-HCV positive were 3.7 times more likely to have anti-HCV than females whose sex partners were anti-HCV negative (P = .039). The proportion of RNA homology between anti-HCV positive females and their male partners (94%) was higher than among randomly selected patients (82%). Sexual transmission of HCV may contribute to the high prevalence of anti-HCV reported in urban settings.