Universal hepatitis B immunization: infant, and infant plus adolescent immunization

Hepatitis B virus (HBV) is one of the world's most widespread infectious ag ents and the cause of millions of diseases and deaths each year. Vaccinatio n programmes aimed at risk groups are important for individual protection, but will not eliminate viral transmission in Europe, since 70% of acute hep atitis B cases are either acquired by sexual activity or are of unknown ori gin. In industrialized countries, HBV infection occurs mainly in young adul ts, however, when the virus is acquired during infancy it leads to extremel y high rates of chronic carriership, contributing disproportionately to the overall pool of HBsAg carriers. This explains why integrating universal HE vaccination into routine infant immunization programmes is the best means for controlling HE in countries with intermediate to high levels of HE ende micity. In countries of low endemicity, universal immunization of adolescen ts may be considered as an alternative to infant vaccination, as this strat egy has a more rapid effect on the epidemiology of the infection. Where fea sible, a double strategy (infant plus adolescent) is the optimal solution. With this strategy, adolescent immunization is necessary only for the time required for the first cohort of immunized infants to reach adolescence. Af ter universal vaccination programmes have been implemented, efforts must be made to sustain vaccine procurement, monitor coverage, check the incidence of acute disease, particularly in immunized cohorts and verify by seroepid emiological studies the progression made in the elimination of HBV transmis sion. (C) 1998 Elsevier Science Ltd. All rights reserved.