Hepatitis C virus infection in China: an emerging public health issue.

Hepatitis C virus now represents a global viral pandemic and is the fourth most commonly reported infectious disease in China. Information on China's national HCV epidemic was limited to cross -sectional seroprevalence studies of special populations, and a national surveillance effort had been launched to inform prevention and control. We analysed novel data from two national databases: (i) China's national medical HCV case report system and (ii) the national disease sentinel surveillance system. Between 1997 and 2012, reporting incidence of medical cases for HCV infection rose from 0.7 to 15.0 cases per 100 000 with the largest burden of disease concentrated among individuals over 35 years of age, rural residents and those tested as part of routine screening. Between 2010 and 2012, disease sentinel surveillance identified the highest HCV seropositive rates among persons who use drugs and haemodialysis patients, with far lower but not negligible rates among sexually active population. The concentration of cases among older age groups is consistent with past studies of age-specific prevalence rates in Asia. Differences across regions and testing modes suggest diverse biological and social forces driving the spread of HCV in China. Surveillance data show ongoing transmission, particularly among persons who use drugs and persons undergoing invasive medical treatments, particularly haemodialysis. Improvements in case detection and data reporting systems will be critical for understanding current drivers of transmission and identifying key areas for prevention.