A modified immunisation schedule for the hepatitis B vaccine Recombivax HB suitable for mass vaccination in childhood.

Following the demonstration of a fully satisfactory immunogenic activity of a hepatitis B vaccination protocol consisting of three doses of Hevac B Pasteur vaccine given at 3,5 and 11 months of age, it was possible to administer this vaccine at the same times as the vaccinations for diphtheria, tetanus and polio which are mandatory in Italy at those ages. We have also shown that both another plasma-derived vaccine, H-B-VAX (MSD), as well as the DNA-recombinant Engerix B (SK&F) are highly immunogenic when given at the same times as the mandatory childhood vaccinations. In this paper we demonstrate that the same schedule can be used for another hepatitis B vaccine prepared by a DNA-recombinant technique, Recombivax HB (MSD) recently introduced in Italy. In fact two doses of this vaccine, the first given at three months of age and the second two months later, resulted in a 100% seroconversion rate and a mean anti-HBs titre of 440 mUI/ml. Although the date are incomplete since the third dose will be given at 11 months of age, we conclude that this hepatitis B vaccine can also be used in the mass vaccination campaigns of infants in Italy, the first of which was initiated in January 1987 in an hyperendemic area near Naples (HBsAg prevalence about 14%). We underline that this mass vaccination campaign is the first in Europe.