Natural history and clinical features of hepatitis C virus infection during childhood: A nationwide, observational survey in Japan

AimFew data on spontaneous clearance rates of cases of mother-to-child transmission of hepatitis C viral (HCV) infection are available in Japan. Furthermore, the treatment courses of interferon-based and direct-acting antiviral agent (DAA) therapies for children are also unclear. Our aim was thus to clarify the long-term natural progression of HCV infection and the treatment outcomes of children in Japan.MethodsWe conducted a combined multicenter, observational survey involving 65 pediatric institutions in Japan. Pediatric HCV infection cases with patients born between 1973 and 2021 were collected over the 11-year period from 2012 to 2022. A total of 563 patients were enrolled, with 190 excluded for having insufficient laboratory data or treatment information, resulting in 373 eligible cases.ResultsOf 328 cases of mother-to-child infection, 34 (10.4%) had spontaneous clearance, with a median time to spontaneous clearance of 3.1 years (range 0.9-7.2 years). Of the total 373 eligible cases, 190 received antiviral therapy (interferon-based therapy, 158; DAA therapy, 32). Sustained virologic response rates after first-line treatment were 75.3% (119/158) and 100% (32/32) for interferon-based therapy and DAA therapy, respectively, with the DAA group showing a shorter time from therapy initiation to viral negativity (2.7 vs. 1.0 months; p = 0.0031).ConclusionsApproximately 10% of Japanese children infected by mother-to-child transmission achieve spontaneous resolution of HCV infection. Our findings indicate that DAA therapy is safe and highly effective in Japanese children, achieving higher sustained virologic response rates and shorter time to clearance of the virus compared with interferon-based therapy. In the present study, 10.4% of Japanese children infected with hepatitis C virus transmitted from mother to child cleared the infection 3.1 years after birth. We also showed that direct-acting antiviral agent therapy is a safe and highly effective treatment. Direct-acting antiviral agent treatment should be provided to prevent transmission from mother to child. image