Hepatitis A and E Viruses Are Important Etiologies of Acute Severe Hepatitis in Asia–Pacific Countries: A Narrative Review

Background/Objectives: Acute-on-chronic liver failure (ACLF) and acute liver failure (ALF) are symptoms of acute severe hepatitis which can result in higher liver-related mortality without liver transplantation following acute hepatitis and acute liver injury in patients with and without chronic liver diseases, respectively. Hepatitis A and E viruses (HAV and HEV) infect humans through the fecal–oral route, causing acute hepatitis A and E. Hepatitis E also causes zoonosis, which causes chronic hepatitis E in immunocompromised hosts. These viruses replicate in hepatocytes and egress into blood and feces through the biliary tract system. Prevention and treatment of these viruses is a major health concern. Methods: This narrative review is the result of a traditional, nonsystematic review. Discussion: The Japan Agency for Medical Research and Development (AMED) HAV and HEV Study Group has recently published two guidelines for HAV and HEV infections. Medical researchers should highlight the importance of HAV and HEV infection, and share various guidelines so that patients infected with HAV and HEV are accurately diagnosed and treated. In Asia–Pacific countries, guidelines for hepatitis A and E to prevent progression to ALF and ACLF are required. Conclusions: It is important to develop and highlight specific treatment and preventive methods, including vaccines, for HAV/HEV. Medical researchers should notice that HAV and HEV infections still play roles in progression to acute severe hepatitis in Asia–Pacific countries.