Failure of hepatitis C therapy in HIV-coinfected drug users is not due to a shift in hepatitis C virus genotype

Because most patients coinfected with hepatitis C virus (HCV) and human immunodeficiency virus (HIV) are injection drug users (IDUs) who might have been exposed to multiple HCV genotypes while sharing needles, coinfection with distinct HCV genotypes could be frequent in them. Blood samples from 203 coinfected IDUs who did not respond to at least 24 weeks of interferon (IFN)-based therapies were analyzed. At baseline, 131 patients had HCV genotype 1, 4 had HCV genotype 2, 52 had HCV genotype 3, and 16 had HCV genotype 4. Changes in HCV genotype were not found in any patient when samples obtained before and after HCV therapy were compared. HCV therapy did not appear to select for IFN-resistant HCV genotypes that might have been present at baseline. Coinfection with distinct HCV genotypes is unlikely in former IDUs coinfected with HIV and does not explain the lower efficacy of HCV therapy in this population.