Background: Although the epidemiology of hepatitis C virus (HCV) infection among children may be rapidly changing, few reports have characterized large nationwide cohorts of children with HCV infection. We, therefore, sought to clarify the epidemiology and natural history of HCV infection in Japanese children born over the last three decades.
Methods: Sixty-five pediatric centers retrospectively and prospectively recruited consecutive, otherwise-healthy HCV-infected children born during 1986 to 2015.
Results: Entry criteria were met by 348 children. Age at initial diagnosis of infection has decreased significantly in recent years. Cirrhosis and hepatocellular carcinoma were not identified. Prevalence of spontaneous clearance and of interferon treatment with/without ribavirin were 9 and 54%, respectively. Maternal transmission has increased significantly, representing over 99% of cases in the last decade. No transfusion-related cases have been seen after 1994. HCV genotype 2 has increased to become the most prevalent in Japanese children. Histopathology examination of liver specimens showed no or mild fibrosis in most children with chronic hepatitis C; none showed cirrhosis.
Conclusions: This largest nationwide cohort study of Asian children with HCV infection spanned the last three decades. None of these Japanese children developed cirrhosis or hepatocellular carcinoma. Maternal transmission increased to account for 99% of cases during the last decade. Genotype 2 now is most prevalent in these children. Histopathologically, most children with chronic hepatitis C showed mild fibrosis or none.
Keywords: Cirrhosis; Genotype; Liver histopathology; Maternal transmission; Natural history.