Intrafamilial transmission of hepatitis C.

To identify intrafamilial transmission of hepatitis C virus, we tested for antibodies to hepatitis C virus (anti-HCV) in serum samples of 160 family members (12 parents, 17 siblings, 73 children, and 58 spouses) of 76 index patients with chronic hepatitis C. Anti-HCV was detected in 14 of 160 family members (8.75%). This positive rate was significantly higher than the anti-HCV-positive rate in age-matched volunteer blood donors in our district (8.75% vs. 1.42%; P less than 0.01). Among 14 members, 5 had normal liver function tests and 9 had hepatitis C. In 4 of 73 children, anti-HCV was detected (5.48% vs. 0.55%; P less than 0.01). In the two children, transmission from mother to child in their childhood was suspected, and in the other children, transmission was from father to child. Furthermore, 7 of 58 spouses (12.1%) had anti-HCV (12.1% vs. 2.13%; P less than 0.01). These results suggest that intrafamilial transmission, especially horizontal infection may play an important role in the spread of hepatitis C.