Prevention of varicella-zoster virus infection in early childhood children: effect of 1 versus 2 doses of varicella vaccine on antibody levels.

OBJECTIVE

This study aimed to ascertain the factors influencing the varicella-zoster virus (VZV) IgG seropositivity and to evaluate the efficacy of varicella vaccination with 1- and 2-dose schedules.

METHODS

A systematic sampling method was employed to recruit subjects. VZV IgG was calculated using the geometric mean concentration (GMC) and a 95% confidence interval (CI). A multifactorial logistic regression model was employed to calculate the odds ratios (OR) and to identify the influential factors for varicella antibody positivity. A generalized additive model for location, shape and scale (GAMLSS) was employed to compare centile reference values and centile curves of antibody levels for different doses of varicella vaccine (VarV).

RESULTS

785 individuals were included. The VarV positivity rate was 57.7% for 1 dose and 84.2% for 2 doses. Varicella antibody positivity was significantly associated with VarV doses and time since last vaccination. The GAMLSS model indicated a decline in VZV IgG over time, with the 2-dose group demonstrating superior performance to the 1-dose group across all centile reference values and curves.

CONCLUSION

A 2-dose schedule is more effective in improving both VZV IgG seropositivity and GMC than a single dose. The inclusion of the VarV in routine immunization programme should be considered.