Burden of chronic hepatitis B and C infections in 2015 and future trends in Japan: A simulation study.

Background: Determining the number of chronic hepatitis B (HBV) and C virus (HCV) infections is essential to assess the progress towards the World Health Organization 2030 viral hepatitis elimination goals. Using data from the Japanese National Database (NDB), we calculated the number of chronic HBV and HCV infections in 2015 and predicted the trend until 2035. Methods: NDB and first-time blood donors data were used to calculate the number of chronic HBV and HCV infections in 2015. A Markov simulation was applied to predict chronic infections until 2035 using transition probabilities calculated from NDB data. Findings: The total number of chronic HBV and HCV infections in 2015 in Japan was 1,905,187-2,490,873 (HCV:877,841-1,302,179, HBV:1,027,346-1,188,694), of which 923,661-1,509,347 were undiagnosed or diagnosed but not linked to care ("not engaged in care"), and 981,526 were engaged in care. Chronic HBV and HCV infections are expected to be 923,313-1,304,598 in 2030, and 739,118-1,045,884 in 2035. Compared to 2015, by 2035, the number of persons with HCV not engaged in care will decline by 59·8 - 76·1% and 86·5% for patients in care. For HBV, a 47·3 - 49·3% decrease is expected for persons not engaged in care and a decline of 26·0% for patients engaged in care. Interpretation: Although the burden of HBV and HCV is expected to decrease by 2035, challenges in controlling hepatitis remain. Improved and innovative screening strategies with linkage to care for HCV cases, and a functional cure for HBV are needed. Funding: Japan Ministry of Health, Labour and Welfare.