IMMUNOGENICITY OF A RECOMBINANT PRE-S2-CONTAINING HEPATITIS-B VACCINEVERSUS PLASMA-DERIVED VACCINE ADMINISTERED AS A BOOSTER

GenHevac B Pasteur is a recombinant hepatitis B vaccine derived from a mammalian cell line and containing HBs as well as pre-S2 antigens. It s immunogenicity was compared to that of the plasma-derived vaccine He vac B Pasteur in a population prime vaccinated 5.5 years earlier with four injections of the same plasma vaccine. The booster injection with either GenHevac or Hevac was administered to 295 subjects with residu al anti-HBs titres below 500 IU/l (group 1: 0-9; group 2: 10-99; group 3: 100-499 IU/l). After four weeks, GenHevac had induced higher anti- HBs responses than Hevac in all groups, particularly among the low res ponders of group 1. Response to the vaccine occurred earlier with GenH evac. Mean anti-pre-S2 production was moderate in all groups for both vaccines (GenHevac: 60 IU/l; Hevac: 31IU/l) and was not found in the 3 2 subjects who produced less than 100 IU/l anti-HBs. The results of th e present study indicate that GenHevac is at least as immunogenic as H evac.