A Serological Investigation on the Immune Effect in Neonates after Recombinant Yeast Hepatitis B Vaccination

Objective To understand the immune effect and immune persistence of recombinant yeast hepatitis B vaccine which has been widely used in neonates.Methods Children aged from 1 and 6 years(born between 2005 and 2011) were selected by using the methods of cross-sectional study and stratified random sampling.Microparticles chemiluminescence analysis was applied in quantitative determination of HBsAg and Anti-HBs.Results The anti-HBs levels of 967 children who received primary immunization decreased with time.The positive rate decreased from 98.06% in the first year to 57.50% in the sixth years(P 0.01),the serum effective protection rate from 95.15% to 37.50%(P 0.01),and geometric mean titer(GMT) from 95.61 mIU / mL(95% CI 69.45 ~ 131.61 mIU / mL) to 3.17 mIU / mL(95% CI 1.20 ~ 8.36 mIU/mL)(P 0.01) in the same period.Dramatically decline was found in the 0 ~ 2 years,and no significant differences were found in the comparisons of the Anti-HBs titer in the 3 ~ 6 years.And anti-HBs GMT was under effective protection level(10 mIU/mL) after 3 years.25.15% of the children's anti-HBs was lower than 1 mIU/mL.Although antibodies decreased with time after primary immunization,the HBsAg positive rate of all children was only 0.34%.The positive rate,the effective protection rate and GMT of one dose booster group were remarkably higher than the primary immunization group,and GMT of the booster group was as 9.93 times as that of primary group.In the booster group,there were no significantly differences of positive rate(P 0.05) and effective protection rate(P 0.05) within 3 years.Conclusion The positive rate,effective protection rate and GMT of recombinant yeast hepatitis B vaccine have remarkably declined after 6 years,but the immune memory is well.So there is no necessity for large-scale booster immunization within 6 years.