title: Recombinant-yeast-derived hepatitis B vaccine in healthy adults: safety and two-year immunogenicity of early investigative lots of vaccine.
abstract: We tested the safety and long-term immunogenicity of two of the early investigative lots of a recombinant-yeast-derived hepatitis B vaccine in immunocompetent adults. Three 10-micrograms doses of recombinant hepatitis B vaccine (Merck Sharp & Dohme Research Laboratories, West Point, PA) were administered by deltoid intramuscular injection at time 0, 1, and 6 months to 65 seronegative adult health workers. Following a complete three-injection course, 98% of vaccinees acquired anti-HBs, 97% at levels greater than 10 mlU/ml, and 95% maintained such "protective" antibody levels at 1 year. At 2 years, 93% retained antibody, but only 68% had levels greater than 10 mlU/ml. In those who responded to vaccination by achieving any detectable level of antibody, the peak geometric mean titer of anti-HBs, measured at 9 months, was 741 +/- 6 mlU/ml; the geometric mean titer fell to 348 +/- 6 at 1 year and to 66 +/- 7 at 2 years. Side effects were trivial, and levels of yeast antibody, as measured by radioimmunoassay, were not changed from prevaccine levels. No serious adverse effects were encountered, and neither type B nor non-B hepatitis occurred in any vaccine. These findings demonstrate that the recombinant yeast hepatitis B vaccine is safe and immunogenic but that 10 micrograms of the early investigative lots of the recombinant vaccine is less immunogenic than 20 micrograms of the plasma-derived vaccine. Recipients of early investigative vaccine lots should be considered for booster vaccination with currently available, more immunogenic vaccine lots.
authors.affiliation: Gastrointestinal Unit, Massachusetts General Hospital, Boston 02114.
authors.forename: L
authors.initials: L
authors.lastname: Butterly
authors.forename: E
authors.initials: E
authors.lastname: Watkins
authors.forename: J L
authors.initials: JL
authors.lastname: Dienstag
mesh_terms: D000328:Adult; D000908:Antibodies, Fungal / Q000032:analysis; D005260:Female; D006510:Hepatitis B Antibodies / Q000032:analysis*; D017325:Hepatitis B Vaccines; D006801:Humans; D008297:Male; D008875:Middle Aged; D011994:Recombinant Proteins / Q000276:immunology; D014611:Vaccination; D014761:Viral Hepatitis Vaccines / Q000276:immunology*; D015003:Yeasts / Q000276:immunology
chemical_list: D000908:Antibodies, Fungal; D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines; D011994:Recombinant Proteins; D014761:Viral Hepatitis Vaccines