Objective: To study the immunologic effect of live attenuated hepatitis A vaccine (H(2) Strain, 10(7.0)TCID(50)) after booster and to compare with the results of 1 dose live attenuated hepatitis A vaccine (H(2) Strain, 10(7.0)TCID(50)).
Methods: 42 susceptibles with negative anti - HAV were selected in Zhengding, Hebei province. Each subject received 3 doses live attenuated hepatitis A vaccine at 0, 2, 6 months and was bled at 1, 2, 6, 7, 9, 12 months after vaccination.
Results: The seroconversion rate at 1 month after the first dose was 81.4% and reached 100% after the second dose. GMT arrived the peak 2,739 mIU/ml at one month after the third dose, before stared declining. The seroconversion rate kept 100% at 12 months after the first dose, but GMT decreased to 979 mIU/ml.
Conclusion: The first dose worked as the base of boostering. A booster dose of live attenuated hepatitis A vaccine could induce secondary immune response well. The immunologic effect after booster dose could match the effect with inactivated vaccine and was better than the results of 1 dose live attenuated hepatitis A vaccine. The program seemed to be useful to the protective effect and the immuno - persistence.