Hepatitis C infection among injection drug users in Stockholm Sweden: prevalence and gender.

Hepatitis C virus (HCV) infection is widespread among injection drug users. Young women seem to be at higher risk of acquiring HCV. To optimize future intervention and prevention measures, we studied the epidemiology of human immunodeficiency virus (HIV), hepatitis B (HBV), and HCV infection among men and women. Inclusion criteria for this cross-sectional multicentre study were: history of ever injecting drugs, age > 18 y, and no previous HIV diagnosis. In 310 participants, plasma/serum samples were analysed for HBV, HIV and HCV (anti-HCV, HCV-RNA, and HCV genotype). HCV antibodies were noted in 268 (86.5%) participants, of whom 207 (77.0%) also had detectable HCV-RNA. Genotypes 1 and 3 dominated, at 35.9% and 33.0%, respectively. Women acquired HCV (but not HBV) to a significantly higher degree (RR 2.97, 95% confidence interval 1.11-7.93) during the first y of injecting drugs. They also recovered spontaneously from HCV infection more frequently (RR 2.49, 95% CI 1.28-4.53). The HCV prevalence of about 50% within 2 y after initiation of injection drug use underlines the need for early intervention efforts. Possible causes for higher HCV prevalence and the implications of favourable spontaneous recovery rates among women should be considered when designing intervention and prevention measures.