Varicella antibody level of children aged 2-7 years old in Baoshan district of Shanghai

[Objective]To observe the immune effect and immune persistence of varicella vaccine,provide the reference for the immunoprophylaxis of varicella control.[Methods]455 children aged 2-7 years old in Baoshan district of Shanghai were selected,which included the children had varicella vaccine immunization history or not.The blood samples of peripheral finger were collected,and the antibody levels were detected and compared.The differences of vaccines and years of immunization in children with immunization history were compared.[Results]The antibody level of children without immunization history increased gradually with increasing age.The antibody level of children with immunization history was significantly higher than that of 2-4 years old and 4-6 years old children without immunization history(t=14.439 and t=3.050,both P0.01).There was no significant difference in antibody level of children between the domestic and imported vaccine.The antibody level of children decreased with increasing years of immunization,and the difference was significant(F=4.529,P0.05).The positive rate decreased from 78.10% of 1 year after inoculation to 66.06% of 3 year after inoculation and 65.12% of 5 year after inoculation,and there was no significant difference in antibody level between 3 year and 5 year after inoculation(χ2=5.061,P0.05).[Conclusion]The varicella vaccine can provide good immune protection.The domestic and imported vaccines have similar effect.The antibody level decreases significantly 3 year after inoculation,so it is suggested that another 1 dose of varicella vaccination should be performed 3 year after first-dose to improve the protective effect.