Effects of a recombinant yeast-derived hepatitis B vaccine in healthy adults.

Under randomized, double-blind conditions, 220 medical students were vaccinated with either a 2.5, 5, 10, or 20 micrograms dose of a recombinant yeast-derived hepatitis B or a 20 micrograms dose of a plasma-derived vaccine. Vaccines were administered at months 0, 1, and 2. After 11 months, all vaccinees received a 20 micrograms booster of the recombinant vaccine. There were no significant differences in adverse reactions between the study groups. Induction of IgE antibodies to yeast was not observed. One month after the third vaccination, seroconversion rates reached 100% in all vaccinees. Mean anti-HBs levels varied between 150 and 1470 IU/l after 3 vaccinations, with the lowest dose resulting in the lowest titres. Following the booster vaccination, dose-dependent effects were no longer observed. These data indicate that the recombinant hepatitis B vaccine is safe and immunogenic for use in man and comparable to the plasma-derived vaccine in terms of safety and efficacy.