High prevalence of hepatitis C virus genotype 1a in Japanese hemophiliacs

Japanese hemophiliacs have received a large number of imported coagulation factors from the USA as well as domestic ones. We investigated the prevalence of hepatitis C virus (HCV) genotypes in 25 hemophiliacs and in 461 patients with chronic hepatitis C in the San-in area, west Japan. The prevalence of HCV genotype 1a was significantly higher in hemophiliacs (36%, P < 0.001) than patients with chronic hepatitis C (0.2%). Furthermore, the mixed infection of different genotypes was significantly more frequent in hemophiliacs (20%, P < 0.0001) compared to chronic hepatitis C patients (1%). These results suggest that Japanese hemophiliacs could be infected with HCV genotype 1a by numerous and repeated infusion of imported coagulation factors from the USA.