Intrafamilial transmission of hepatitis C virus: the important role of infections between spouses.

To investigate the intrafamilial transmission of hepatitis C virus (HCV) and related risk factors, anti-HCV antibodies in 186 family members of 48 index patients were studied. The index patients were anti-HCV-positive and had chronic liver disease. Overall, 10 family members (5.4%) were positive for anti-HCV, indicating a higher prevalence of anti-HCV among family members than among the Taiwanese general population. Spouses had the highest prevalence (21%) of anti-HCV, with older age and longer duration of marriage of index patients the most evident risk factors. HCV RNA, recovered from the infected couples by reverse transcription-nested polymerase chain reaction and subsequently sequenced directly, was identical at the nucleotide level in 3 of the 4 couples studied, and the remaining couple had a homology of greater than 96%. These results strongly support that interspousal transmission may be the most important route of intrafamilial spreading of HCV, and thus sexual transmission, although with low efficiency, should be considered important in HCV infection.