Absence of hepatitis C virus transmission but frequent transmission of HIV-1 from sexual contact with doubly-infected individuals.

Hepatitis C virus (HCV) is transmitted through infected blood and blood products, but evidence of other routes of transmission is less clearly understood. In a study designed to examine human immunodeficiency virus (HIV) transmission, the prevalence of HCV has also been measured. Sixty-one couples were analysed, 30 in which partners were at risk through sexual contact alone, of whom 12 (40%) became infected with HIV and none with HCV. Thirty-one partners were exposed sexually and additionally through intravenous drug use. Of these, 16 (52%) became infected with HIV and 25 (80%) contracted HCV infection. These findings support the evidence of others that HCV is only rarely transmitted by sexual intercourse in heterosexual relationships and that HIV is not a co-factor for HCV transmission.