Long-Term Protection of Hepatitis B Vaccine: Lessons from Alaskan Experience after 15 Years

Hepatitis B virus (HBV) is highly infectious and causes serious health problems worldwide. Approximately one third of the world's population has been infected, and about 400 million people have become chronic carriers (1, 2). The infection results in a wide spectrum of liver diseases, ranging from hyperacute fulminant hepatitis to refractory hepatic cirrhosis and hepatocellular carcinoma (3-5). Infection that occurs at a young age frequently results in chronic carriage of the virus. In contrast, only a small proportion of patients become chronic carriers if they contract the infection in adolescence or adulthood. Once the infection becomes chronic, HBV or part of the viral genome usually persists in the liver for the carrier's lifetime (5). The carriers are not only reservoirs of the virus but also victims of chronic liver diseases themselves (3). Thus, control of HBV infection, especially in terms of preventing chronic carriage of the virus, is extremely important.

Hepatitis B depends on 3 components: an infectious source, a susceptible host, and an established route of transmission (2). The most efficient way to control hepatitis B is to prevent someone from contracting it rather than treating those who have already become infected. Two main approaches lead to achieving this goal: interrupting the route of transmission and immunizing the susceptible host. Although immunization is more effective, public health measures should include both approaches. In the …