Changing epidemiology of liver disease in Asia: Dual infection of HBV and HCV.

Transmission of hepatitis B virus (HBV) and hepatitis C virus (HCV) is similar regarding the mode of transmission and related risk factors. Therefore, it is not rare to encounter dual HBV/HCV infection in populations at risk of parenteral exposure to hepatitis viruses. Besides, in HBV endemic countries before the era of global HBV vaccination, dual HBV/HCV infection was clinically significant likely because of HCV superinfection over pre-existing HBsAg carriage. Universal childhood HBV vaccination was implemented worldwide since 1992. Public education programs for prevention of new hepatitis viral infections have been actively promoted recently by World Health Organization. Apart from preventive measures, potent anti-HBV agents effective in the control of viral replication have been introduced gradually in the past three decades. Direct acting antiviral agents capable of curing HCV infection in more than 97% of patients with chronic hepatitis C have also been widely implemented in the past decade. These interventions will change the epidemiology of new HBV or HCV mono-infection and dual HBV/HCV infection. Understanding the evolution in the epidemiology of dual HBV/HCV infection is important for evaluation of current public health policy towards infectious disease control in different countries. The changing prevalence of dual HBV/HCV infection in certain Asia-Pacific countries will be re-visited based on endemicity of HBV or HCV, as well as in populations at risk of parenteral viral infection.