Hepatitis B vaccination: current status.

BACKGROUND: Hepatitis B remains a crucial Public Health problem worldwide, with a numerical impact of infected persons and long term sequences higher than other infectious diseases preventable by vaccines. Around 75% of the world population is living in areas where HBV is endemic (Africa, most of south America, eastern Europe, eastern Mediterranean basin, south-eastern Asia, China and Pacific islands except Australia, new Zealand and Japan); 5-15% of these populations are affected by chronic HBV infection. Rates of chronicity depend on the age of exposure to HBV. Newly infected adults generally clear the infection and only about 5% become chronic carriers of the virus. Infected children rarely develop clinical disease but 25-90% become chronic carriers. Over two billions of persons worldwide have been infected in their life and 350 millions are chronic carriers of HBV. About 25% of the chronic carriers will die of cirrhosis or hepatocellular carcinoma. In recent years control of the spread of HBV has been achieved by the large-scale availability of safe and effective vaccines. This review summarizes the current perspective and use of hepatitis B vaccination, with particular attention to implementation needs and results in Italy, the first country that has introduced universal vaccination against hepatitis B.