Observation on immunogenicity of domestic freeze-dried live attenuated varicella vaccine and immunity persistence one year after vaccination

Objective To evaluate the immunogenicity and immunity persistence of domestic freeze-dried varicella attenuated live vaccine (VarV-Fd). Methods Totally 119 children aged 7-13 years were recruited in Ningbo and then divided into two groups. Domestic VarV-Fd and imported VarV-Fd were vaccinated respectively for the children in two groups and serum antibody levels to varicella-zoster virus were detected by antibody membrane immune-fluorescence assay. Results Six weeks after vaccination, the antibody geometric mean titer was 1∶160.7 in children receiving domestic VarV-Fd and 1∶204.0 in children receiving imported VarV-Fd, the difference had no statistical significance (P=0.596). The effective rates of both vaccines were 96.7% and 100%, the difference had no statistical significance (P=0.496). The antibody level of domestic VarV-Fd 1 year after vaccination was significantly lower than that 6 months after vaccination. (P0.001). Conclusion Both the domestic of VarV-Fd and imported VarV-Fd had good immunogenicity, but the immunity level by domestic VarV-Fd will decrease over time.