World-wide control of hepatitis B.

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It has been 30 years since the Third World Health Assembly convened a WHO Expert Committee to consider investigation, control, and prevention of viral hepatitis. During that time, significant advances have been made in understanding the etiology and epidemiology of viral hepatitis. Technological advances of the 1970s enabled widespread rapid diagnosis and the development of vaccines of high efficacy. These advances have allowed the implementation of control programs on a global scale. Because liver cancer (PHC) is among the 10 most common cancers in the world, the link between PHC and viral hepatitis is important. Up to 80% of these cancers are attributable to the hepatitis B virus. Although the development of PHC is not associated with acute hepatitis B virus itself, the chronic HBV carrier state may be classified as a precancerous lesion. Task forces have been convened consider implementation of hepatitis control programs, especially in countries where the infection is hyperendemic. The most important prevention method is active immunization, but vaccination strategies must consider differences in geographical patterns of prevalence. In areas of low endemicity, such as North America, Western Europe, and Australia, immunization of selected high risk groups is suggested. In areas of high endemicity, such as sub-Saharan Africa, southeast Asia, and China, large-scale vaccination of infants is recommended, similar to DPT and polio vaccination programs. Current hepatitis B vaccines are favorable to mass infant immunization because of their high tolerability, excellent immunogenicity, and their ability to induce primary humeral antibody response. However, these vaccines are available in insufficient quantities and the costs are too high for use on a large scale. Newer vaccines, based on recombinant DNA techniques (rather than plasma-derived vaccines) show promise in increasing the quantity and reducing the cost of hepatitis B vaccines.