Risk factors for hepatitis C virus infection among blood donors in northern Thailand.

BACKGROUND

The epidemiology, virology, and risk factors for hepatitis C virus (HCV) infection among blood donors in northern Thailand have not been extensively evaluated.

STUDY DESIGN AND METHODS

We did a prospective matched case-control study of blood donors who tested positive for HCV and were confirmed by recombinant immunoblot assay or nucleic acid testing. Infected donors were matched with one to four HCV-uninfected donors for sex, age +/- 5 years, and donation at the same site within 15 days of the HCV-positive donor. Married donors were invited to bring their spouse for HCV testing.

RESULTS

Among 166 matched sets, a history of intravenous drug use (IDU), reported by 58 HCV infected donors (35.5%) and 2 HCV-negative donors, was strongly associated with HCV infection (odds ratio [OR], 107.6; 95% confidence interval, 14.8-780.7). In multivariate analysis among donors without a history of IDU, significant risk factors included a history of a blood transfusion (OR, 28.8), immediate family with a history of hepatitis/jaundice (OR, 4.4), six or more lifetime sexual partners (OR, 2.7), and increased frequency of blood donation (OR, 0.9). Six of 45 spouses of HCV-infected donors, and none of 44 spouses of uninfected donors, were HCV positive (p = 0.005).

CONCLUSION

Our data indicate that illicit IDU and a history of transfusion are important risk factors for HCV infection in Thailand. Also, our data suggest there may be some risk of transmission by sex or other close contact between spouses.