Peer-reviewed article

Varicella epidemiology, susceptibility and cost burden in Chongqing China: implications for prevention and control strategies.

Ning Yao, Shanshan Kuang, Jiuyang Deng, Yang Liu, Hua Zhao et al. · 18 Jun 2026

Abstract

BACKGROUND: To characterize the epidemiological profile, population seroprotection levels, and economic impact of varicella in Chongqing, and to provide evidence to optimize immunization strategies to reduce incidence and economic burden. METHODS: The epidemiological trends of varicella in Chongqing were ascertained from routine surveillance data (2011-2024). Population sero-epidemiology was evaluated using a randomized cross-sectional serosurvey (n = 960, 2024), and economic burden was estimated from 14,779 outpatient and 298 inpatient cases (2019-2022). Statistical analyses (descriptive statistics, Chi-squared test, Kruskal-Wallis test, and Wilcoxon rank-sum test) were conducted to quantify incidence trends, factors associated with antibody levels, and heterogeneity in economic burden. RESULTS: A total of 301,714 cases were reported during 2011-2024, with 53.56% in children < 15 years. Incidence exhibited an inverted U-shaped trend. The overall crude varicella IgG seroprevalence was 78.33% (geometric mean concentration, GMC: 351.3 mIU/mL). Notably, children (< 15 years) showed a significant seroprotection gap (seroprevalence: 70.54%; GMC: 240 mIU/mL), which aligned with their disproportionately high incidence. Two-dose vaccination was associated with significantly higher seropositivity (83.50% vs. 66.07%) and GMC (343.7 vs. 189.1 mIU/mL) than one dose (p < 0.01). Adults aged > 50 years exhibited the highest GMC (744.7 mIU/mL) and seropositivity (96.15%), aligning with the lowest incidence recorded in 2024. The pediatric inpatients (< 15 years) had a higher burden ($1375.74 vs. $1012.70, p < 0.01) than individuals over 15 years. CONCLUSIONS: Varicella incidence remains high and children show suboptimal seroprotection against varicella in Chongqing. The disease imposes a substantial financial burden, particularly among pediatric inpatients. It is recommended to expand two-dose varicella vaccine immunization coverage to reduce both incidence and disease burden.