COMPARATIVE IMMUNOGENICITY IN CHILDREN OF MAMMALIAN CELL-DERIVED RECOMBINANT HEPATITIS-B VACCINE AND PLASMA-DERIVED HEPATITIS-B VACCINE

Three doses of hepatitis B vaccine were given at 2,4 and 9 months of age to 220 Senegalese infants living in the Dakar area of Senegal. Half of the infants received 5-mu-g plasma-derived hepatitis B vaccine (Hevac B) and the remainder 20-mu-g mammalian cell-derived recombinant hepatitis B vaccine (GenHevac B). Both vaccines contain S and pre-S2 encoded proteins; however, the recombinant vaccine had a much higher pre-S2 content than the plasma-derived vaccine. Adverse reactions to both vaccines were limited to mild and transient soreness at the injection site. Fever was reported in 14-21% of the infants and was likely to be related to DTP-polio vaccine which was given simultaneously. After the two first doses, seroconversion rates and geometric mean titres of anti-HBs were higher in infants receiving the recombinant vaccine than in infants receiving the plasma-derived vaccine. After completion of vaccination, all infants in both groups had protective levels of anti-HBs antibodies. The recombinant vaccine induced more rapidly antibodies directed against S and pre-S2 epitopes. Anti-pre-S2 antibodies were detected after the first injection of GenHevac B and only after the third injection of Hevac B. From the data, GenHevac B vaccine is expected to be as effective as Hevac B vaccine for controlling hepatitis B infection.