Impact of immunization strategies, public health and social measures on the incidence of varicella among children aged 0-14 years in Quzhou City.

This study evaluates the impact of different immunization strategies and public health and social measures (PHSMs) on varicella incidence among children in Quzhou. Data on varicella cases among children aged 0-14 y in Quzhou from 2006 to 2022 were collected. An interrupted time-series (ITS) model was used to analyze trends in monthly varicella incidence during the implementation of the single-dose and two-dose vaccination strategies and the PHSMs. ITS analysis indicated that, following the introduction of the two-dose strategy, the varicella monthly incidence rate decreased immediately by 8.193 per 100,000 (p = .029). After the implementation of PHSMs, it also decreased immediately, with a reduction of 13.518 per 100,000 (p = .006). In terms of long-term effectiveness, neither the two-dose immunization strategy nor the implementation of PHSMs produced a sustained and significant reduction in varicella incidence. The effectiveness of the two-dose strategy may have been constrained by the low second-dose VarV coverage in Quzhou, which ranged from 46.35% to 60.65%, well below the 80% threshold recommended by the World Health Organization. Although the implementation of PHSM can serve as a useful supplementary approach to preventing childhood varicella, their influence on transmission dynamics appears relatively limited.