Characteristics of hepatitis C virus among intravenous drug users in Iceland.

According to antibody analysis, approximately two of every three intravenous drug users in Iceland have become infected with hepatitis C virus (HCV). In this study, serum samples from 55 HCV antibody-positive intravenous drug users (39 males and 16 females) were analyzed by polymerase chain reaction, and the viral strains were grouped into genotypes. Only three genotypes--1a, 3a, and 1b--were found among the drug users. Of 40 persons who were positive by polymerase chain reaction, 23 (57.5%) had type 1a, 15 (37.5%) had type 3a, and one (2.5%) had type 1b. One serum sample was untypeable. HCV viral RNA was detectable in 84.6% of the males and 43.7% of the females, which is a significant difference between the sexes (p < 0.01). In addition, 41 randomly selected HCV antibody-positive intravenous drug users (17 males and 24 females) were tested for HCV viral RNA with a commercially available polymerase chain reaction technique. In this subset of drug users, 76.4% of the males and 33.3% of the females had detectable HCV RNA in their serum, which is also a significant sex difference (p < 0.01). This study shows that two HCV genotypes predominate among intravenous drug users in Iceland, and the results indicate that women eliminate virus more effectively than men.