Abstract
The purpose of this study was to investigate the changes in anti-HBs IgG levels after booster vaccinations in anti-HBs negative infants of HBsAg-positive mothers. After primary vaccination, the immunization effects of different dosages of booster vaccinations of hepatitis B vaccine (CHO) were compared.
A group of 472 newborns were vaccinated with three-dose hepatitis B vaccine at birth, 1 mo and 6 mo of age. Blood serum was collected within 6–12 mo after the third dose, and HBsAg, anti-HBs and anti-HBc levels were determined. Of this group, 101 infants who were both anti-HBs and HBsAg negative were revaccinated with 20 μg hepatitis B vaccine (CHO), and their antibody titers were monitored.
Among these 101 infants, the anti- HBs positive rates (defined as anti-HBs ≥ 100mIU/ml) differed after the first and the third dose (79% and 90%, respectively (p < 0.05), while differences in the corresponding geometric mean titers (GMTs) were not statistically significant (629 ± 3 mIU/ml and 572 ± 3 mIU/ml respectively, p < 0.05). The anti-HBs GMTs after booster vaccination were 10-fold larger than those before booster vaccination.
We conclude that a single booster dose is generally adequate for infants of HBsAg-positive mothers, whereas a further booster dose should be given for non-responders.
Disclosure of Potential Conflicts of Interest
No potential conflicts of interest were disclosed.
Acknowledgments
We are grateful to the children and parents who volunteered to participate in the study and to the doctors in the Changshan, Kaihua, Yuhuan and Shangyu counties Center for Disease Control and Prevention. This study was supported by a grant from the scientific research fund of medical and health in Zhejiang province (No. 2009A035)