Long term protection after hepatitis A and B vaccination : an update

Viral hepatitis continues to be a cause of considerable morbidity and mortality in the world. On worldwide basis, approximately 1.4 million cases of hepatitis A are reported every year. The true incidence, however, has been estimated to be 3 to 10 times higher. Regarding hepatitis B, more than a third of the world's population has been infected. The World Health Organization has estimated (2002) that there are 367 million chronic carriers of hepatitis B worldwide, and approximately 1 million deaths per year as a conse- quence of chronic complications and acute fulminant disease. Hepatitis B vaccines have been licensed since 1982, hepatitis A vaccine since 1992. In 1996, a combined hepatitis A and B vaccine became available. An update on the long term protection conferred by hepatitis A and hepatitis B vaccines is given in the following para- graphs.