Transmission of hepatitis C virus in Taiwan: prevalence and risk factors based on a nationwide survey.

A nationwide community-based survey on hepatitis C virus (HCV) was carried out in seven townships in Taiwan. A total of 11,904 men aged 30-64 years were recruited for testing for antibodies against HCV (anti-HCV) by second-generation enzyme immunoassay. A total of 272 seropositive cases and 282 seronegative controls were interviewed to explore risk factors for HCV infection in the study areas. Spouses of 214 seropositive cases were identified to assess the concordance of seropositivity of anti-HCV between spouses; genotypes of HCV were also tested in 26 couples who were both seropositive. A significant geographic variation in seroprevalence of anti-HCV was observed in the study townships (1.6-19.6%). Blood transfusions, medical injections, acupuncture and tattooing were related to an increased anti-HCV seroprevalence showing multivariate-adjusted odds ratios of 8.6, 2.5, 3.1, and 2.2, respectively, with corresponding population attributable risk percentages of 25%, 57%, 16%, and 3%, respectively. The anti-HCV prevalence in spouses of index cases (24%) was significantly higher than that observed in the general population of the study areas (4%). However, a striking interspousal discrepancy in HCV genotypes (20/26 = 77%) was observed among both seropositive couples. Common exposures to medical injections and acupuncture were reported by 15 (58%) of these couples. This study identified some endemic areas of HCV infection in Taiwan. Iatrogenic factors were common vehicles for HCV infection, and a concordance of anti-HCV seropositivity between spouses may primarily be due to extrafamilial iatrogenic infectious sources in study areas.