RESUMEN
The aim of this work is to evaluate a major epidemiological problem--human hepatitis B virus (HBV) infection--in the world and in Portugal--reinforcing WHO's view that it is a worldwide health problem. Portugal is considered a risk area for HBV infection, with 30% of the population having had contact with the virus and 1 to 5% of chronic carriers (100 to 150,000 persons). Deficient information, education and sanitary conditions aggravate the national situation, urging for official measures that may, in future, lead to a status of controlled infection (less than 0.1% chronic carriers). We propose an educative and informative campaign, the fulfillment of sanitary measures legally controlled as well as the central support for vaccination against HBV. Some of the fundamental points for a legal document that institute a national program for HBV infection control are proposed. At present, cost-benefit relation seems to be favourable--but an adequate plan considering scientific and technical criteria is needed and essential to guarantee that benefits will outweigh investment in terms of Public Health. Recombinant vaccines, obtained by genetic engineering, are referred as the preferential type of vaccine to choose.