Implementation and Impact of HAV and HBV Vaccination Programs in South America.

Viral hepatitis A and B virus are considered an important public health problem in most of South American countries. Its distribution and prevalence are highly heterogeneous all over the continent, depending on geographic, socioeconomic and cultural factors. The hepatitis A virus is transmitted through the oro-fecal route. Although it usually causes a self-limited disease, it is still responsible for some cases of fulminant hepatitis in children and adults. The universal vaccination program against hepatitis A in infants in some countries such as in Argentina, has brought significant reduction in cases of acute liver failure and liver transplantation. Hepatitis B virus (HBV) infection is transmitted through percutaneous and mucosal exposure to infective body fluids. Sexual transmission seems to prevail in most countries, but vertical and horizontal transmission in the early life predominates in highly endemic areas, such as the Amazonia. Around 20 % of HBV carriers in Amazonian are also infected with delta virus. Universal and high risk groups HBV immunization programs implemented in different countries drastically decreased HAV and HBV morbidity and mortality. However, the goal to eliminate both virus infections from this region has not been achieved yet. It is necessary to insure that the existent programs are sustained over time. [ABSTRACT FROM AUTHOR]