Hepatitis B vaccines: protective efficacy and therapeutic potential.

Worldwide, two billion people have at some time been infected by hepatitis B virus, 370 millions suffer from chronic infection and around one million die each year from HBV-related liver diseases of which liver cancer is the ultimate stage. Vaccination is the measure that is most effective in reducing the global incidence of hepatitis B and hepatitis B vaccines have now been available for over 20 years. The first hepatitis B vaccine was prepared from inactivated hepatitis B surface antigen particles purified from plasma of asymptomatic carriers of hepatitis B virus. Knowledge of the structure and genomic organization of hepatitis B virus has led to development of the first DNA recombinant vaccine. In preventing hepatocellular carcinoma development, hepatitis B virus vaccines are considered as the first available cancer vaccine. HBV vaccines have recently taken on a new role as therapeutic vaccines as an attempt to cure or to control hepatitis B virus infection in persistently infected individuals.