ABSTRACT
Objective To analyze the changes of serum antibody levels of children in Changning District of Shanghai City, who received the second dose of varicella vaccine at one year after the first dose thereof.Methods A total of 206 children aged at 1 to 3 years in Changning District who had received one dose of varicella vaccine were included as objects of observation in the observation group.They received the second dose of varicella vaccine at one year after the first dose thereof.Their venous blood was collected before the second dose thereof as well as and at 35 to 42 days thereafter, and the varicella antibody level was tested through Fluorescent Antibody to Membrane Antigen(FAMA) assay so as to compare the difference between the antibody level before the second dose of varicella vaccine and that thereafter.Results The varicella-zoster virus(VZV) antibody titers of the blood serum before and after the second dose of varicella vaccine for the objects of observation were compared.The geometric mean titers(GMT) of the antibody before and after the second dose of varicella vaccine were 1∶11.90 and 1∶71.04, respectively, with the antibody level of the latter significantly higher than that of the former (t=18.1, P<0.01), which showed significant difference between the two.The objects of observation whose antibody levels increased to over 4 times their original antibody levels occupied 82.52% of the total objects of obervation.Conclusion The second dose of varicella vaccine received at one year after the first dose thereof can effectively improve the VZV antibody titer in the blood serum of immunization recipients.