Prevalence of hepatitis C virus in family members of patients with hepatitis C.

To investigate the prevalence of hepatitis C virus in the family members of patients with hepatitis C, we examined antibody to hepatitis C virus with a second-generation enzyme-linked immunosorbent assay and viral RNA with a combined assay of reverse transcription and polymerase chain reaction in sera. Among 219 (75 spouses, 110 children, and 34 others), 26 (12%) were antibody positive. The positive rate of antibody to hepatitis C virus was significantly higher than that of the control group (2.0%) and of volunteer blood donors in our district (1.5%), and it increased with age. In particular, the positive rate of antibody to hepatitis C virus among spouses was high (24%). Among family members with elevated ALT, 59% were antibody positive, which was significantly higher than that of the control group (11%). Of the 26 who were antibody positive, 21 (81%) had viral RNA, whereas of the 70 who were antibody negative, only one (1.4%) had viral RNA. These data suggest that hepatitis C virus was transmitted by the infrafamilial route during long duration of contact with patients or sexual transmission. In family members, hepatitis C viral infection is the main cause of liver disorder, and many who were antibody-positive with a second-generation enzyme-linked immunosorbent assay had viremia in the sera.