Hepatitis B vaccination in countries with low endemicity

(1) Hepatitis B is less frequent in rich countries than in the rest of the world. The prevalence of HBs antigen (a measure of the risk of viral transmission) ranges from less than 0.1% in northern Europe to 1-5% in southern Europe and 8-20% in many African and Asian countries. (2) Initial recommendations to vaccinate only those in high risk groups had no apparent impact on the hepatitis B transmission rate. Changes in behaviour linked to the AIDS pandemic have coincided with a fall in the incidence of acute hepatitis B. (3) The main limitation of immunisation strategies restricted to high risk groups is the fact that no known risk factor is identified in over 30% of cases of acute hepatitis B. (4) All rich countries have recommended routine screening for hepatitis B in pregnant women, and immunisation of newborns whose mothers carry HBs antigen. (5) In countries with low endemicity, HBV transmission usually occurs after the age of 20. Universal vaccination of infants would, therefore, have no effect on the HBV transmission rate for 15-20 years, and then only if the coverage was extensive. Countries in northern Europe, where the prevalence of HBV infection is the lowest in the world, together with Canada, Switzerland and Australia, have not recommended universal immunisation of infants. (6) Universal immunisation of adolescents covers a population closer to the ages most at risk. Only northern European countries have not adopted this policy.