Persistence of anti-HBs antibodies in health care personnel vaccinated with plasma-derived hepatitis B vaccine and response to recombinant DNA HB booster vaccine

Long-term persistence of specific antibodies after primary immunization against HBV infection has been reported. In this study, we evaluated the persistence of anti-HBs in vaccinees 6 years after primary immunization and the response to a booster dose using a recombinant DNA yeast-derived HB vaccine. An 85.4% seroprotection rate was observed after 6 years with a significantly higher seroprotective rate in those subjects who received four doses of vaccine primary immunization as compared with those who received three doses (93.9% versus 67.2%, p < 0.001). One month after receiving the booster dose, 98.6% of the subjects had an anamnestic type of response. The GMTs were found to decrease progressively with increasing age. The antibody levels after booster dose were higher than those attained at the end of primary immunization and reflected the trend seen before the administration of the booster. These results are consistent with the existence of an effective immunological memory in HB vaccine responders. Subjects who received four doses during primary immunization were better seroprotected and had a higher seroprotection rate after the booster dose.