A Study on the Effect of Booster Vaccinations in Anti-HBs Declined Adolescents

Objective To investigate the changes in Antibodies to hepatitis B virus surface antigen(Anti-HBs)levels after booster vaccinations and to compare the immunological effects of different doses in adolescents with Anti-HBs Decline who received primary immunization 12-15 years ago.Methods Adolescents who have received fundamental immunity of hepatitis B vaccine in infancy were detected for HBsAg,Anti-HBs and Anti-HBc by chemiluminescence detection.HBsAg and Anti-HBc negative children with Anti-HBs﹤10 mIU/ml were divided into three groups according to their Anti-HBs titer levels:GroupⅠ(﹤0.1 mIU/ml),GroupⅡ(0.1-1 mIU/ml)and GroupⅢ(1 mIU/ml),and then immunized 10 ug Hepatitis B Vaccine made by recombinant deoxyribonucleic Acid(DNA)techniques in Hansenula Polymorpha Yeast(HepB-HPY)on a 0-1-6 month schedule and Anti-HBs antibody levels were tested one month after the first and third dose,respectively.Results Among 453 adolescents,the Anti-HBs positive rates after using first dose in different groups were 67.96%,85.61%,and 97.60%,respectively.There were statistically significant differences in antibody titer(χ~(2)=132.88,P﹤0.05),and the Geometric Mean Concentrations(GMCs)were 37.31 mIU/ml,152.77 mIU/ml,and 1310.27 mIU/ml,respectively(F=86.11,P﹤0.05).Anti-HBs positive rates after using third dose in different groups were 99.00%,99.21% and 99.49%,respectively,and statistically significant differences were found among three groups(Fisher exact probabilities,P﹤0.05).The GMCs were 1714.67 mIU/ml,1502.32 mIU/ml,and 3383.68 mIU/ml,respectively(F=16.59,P﹤0.05).The positive rates of antibody of the 425 adolescents were 87.76% and 99.29% after first and third doses o of immune booster.Conclusion 12-15 years old adolescents with Anti-HBs﹤10 mIU/ml after fundamental immunity of hepatitis B vaccine need booster immunization.The effect is better for adolescents with a relatively higher Anti-HBs titer before booster,and the effect of three doses booster is better than only one dose.