Strategies for prevention and control of hepatitis B and hepatocellular carcinoma.

Hepatitis B represents a serious public health problem in all parts of the world, and particularly in hyperendemic areas, where the majority of infections occur in childhood. As this infection in early life leads frequently to chronic infection, the prevalence rates of long-term sequelae, such as chronic active hepatitis and cirrhosis, are high. In addition, recent epidemiological, virological and molecular biological studies have provided evidence that persistent or past infection with hepatitis B virus plays an important role in the development of hepatocellular carcinoma (HCC). Although environmental control and the use of passive immunization have proved useful in reducing hepatitis B infections, the most important method of achieving widespread prevention of hepatitis B and its chronic sequelae is active immunization. Vaccines containing purified hepatitis B surface antigen (HBsAg) have been prepared and shown to be both highly immunogenic and efficacious. Depending on the different geographical patterns of hepatitis B prevalence and the availability of vaccine, a variety of vaccination strategies have been proposed ranging from limited to large-scale vaccine administration. Targeted vaccination of selected high-risk groups, including infants of HBsAg-carrier mothers, might be reserved for areas of low prevalence of infection, while large-scale vaccination should be considered for intermediate- and high-endemicity areas. In the latter case, effective control of hepatitis B could be achieved when sufficiently large population groups can be immunized prior to exposure, e.g., during infancy or early childhood. The prerequisite for large-scale vaccination campaigns is the production of large quantities of low-cost vaccine.(ABSTRACT TRUNCATED AT 250 WORDS)