Hepatitis delta virus as a global health problem

As a defective virus requiring helper functions of the hepatitis B virus (HBV), the hepatitis delta virus (HDV) develops only in patients with hepatitis B surface antigen (HBsAg); its presence aggravates the course of the underlying HBV infection. There is no specific prophylaxis against HDV, and its inactivation kinetics by physical and chemical agents are largely unknown. Thus, prevention of HDV in the HBsAg carrier at risk of superinfection is limited to environmental and barrier measures only. As normal persons are efficiently protected from HDV by hepatitis B vaccination, the risk of HDV is another indication for hepatitis B vaccination of at-risk individuals.