Objective: To evaluate the booster immunization effect to non-and-low response children after 3 doses HepB immunization.
Methods: Non-and-low response infants born in 2004 2005 administered 3 doses of HepB at 0, 1, 6 months in Guangzhou, Beijing and Zhejiang were divided into 4 groups randomly, and boosted 3 dose of 4 different types of HepB at 0, 1, 6 months.
Results: The GMC of non-and-low response children in group A (before booster), group B (after 1 dose booster) and group C (after 3 dose booster) were 18.66 mIUml, 88.82 mIU/ml, 178.24 mIU/ml respectively; the proportion of non-responders in three groups were 20.4%, 9.1%, 1.9% respectively. In 103 non-and-low response children, proportion of titers of more than 100 mIU/ml of group B and group C were 61.2% and 84.5%, and there was statistical significant difference (chi2 = 14.13, P < 0.01). The GMC after 3 doses revaccination with four kinds of HepB, included 5 microg HepB-Y, 10 microg HepB-Y, l0 microg HepB-CHO, 10 microg HepB-HY were 168.8 mJU/ml, 174.7 mIU/ml, 184.9 mIU/ml, 182.9 mIU/ml respectively. Proportion of titers of more than 100 mIU/ml for four kinds HepB were 79.0%, 85.7%, 88.2% and 84.6% respectively, and there was no significant difference (chi2 = 0.75, 0.05).
Conclusion: There were no different of seroconversion rate between study population received 1 dose and 3 dose booster (P > 0.05), but high titer was observed after 3 dose booster. The four kinds of HepB, including 5 microg HepB-Y,10 microg HepB-Y, 10 microg HepB-CHO, 10 microg HepB-HY had the same immunization effect after 3 doses revaccination at 0, 1, 6 months to non-and-low response children.