title: Persistence of anti-HBs and protective efficacy after administration of hepatitis B vaccine.
abstract: To evaluate the effect of hepatitis B vaccine on the persistence of anti-HBs and its efficacy in preventing hepatitis type B, anti-HBs and anti-HBc levels were studied over a period of 5.5 years. Plasma-derived hepatitis B vaccine, containing 20 micrograms of HBsAg protein, was injected subcutaneously in 122 healthy medical staff members, followed by two identical injections 1 and 6 months later. Anti-HBs and anti-HBc levels were then measured by radio-immunoassay. The anti-HBs titres were expressed as the sample/negative (S/N) ratios, and an S/N ratio of more than 2.1 was considered positive. The mean (and s.d.) anti-HBs titre peaked 7 months after the first vaccination with an S/N ratio of 153.6 +/- 149.8, after which it decreased with time. The mean anti-HBs titre dropped to an S/N ratio of 8.0 +/- 5.1 5.5 years after the first vaccination. The percentage of vaccinees who were anti-HBs positive also gradually decreased with time after a peak of 84.2% at 7 months following the first vaccination. The percentage of vaccinees who were anti-HBs positive was 38.9% 5.5 years after the first vaccination. The anti-HBc level was not positive in all subjects during the observation period. Five vaccinated volunteers who had developed anti-HBs after the basic vaccination, but whose acquired antibody level became negative within 4.5 years following the first vaccination, were administered a booster dose of 20 micrograms of HBsAg 4.5 years after the first vaccination. Only one of these subjects did not respond to the booster vaccination.(ABSTRACT TRUNCATED AT 250 WORDS)
authors: Third Department of Internal Medicine, Kumamoto University Medical School, Japan.
authors: K
authors: K
authors: Yoshida
authors: S
authors: S
authors: Fujiyama
authors: T
authors: T
authors: Sato
mesh_terms: D000328:Adult; D005260:Female; D006509:Hepatitis B / Q000276:immunology / Q000517:prevention & control*; D006510:Hepatitis B Antibodies / Q000032:analysis*; D006512:Hepatitis B Core Antigens / Q000276:immunology; D017325:Hepatitis B Vaccines; D006801:Humans; D007117:Immunization, Secondary; D008297:Male; D011863:Radioimmunoassay; D013997:Time Factors; D014611:Vaccination; D014614:Vaccines, Synthetic; D014761:Viral Hepatitis Vaccines
chemical_list: D006510:Hepatitis B Antibodies; D006512:Hepatitis B Core Antigens; D017325:Hepatitis B Vaccines; D014614:Vaccines, Synthetic; D014761:Viral Hepatitis Vaccines