Overview of the outbreak of varicella in Zhejiang Province from 2019 to 2022 and analysis of associated factors for breakthrough cases
10.3760/cma.j.cn112150-20231104-00312
- VernacularTitle:2019—2022年浙江省水痘突发疫情概况及突破病例相关因素分析
- Author:
Xuan DENG
1
;
Xinrui LIU
;
Yang ZHOU
;
Lingzhi SHEN
;
Rui YAN
;
Xuewen TANG
;
Yao ZHU
;
Xiaoping XU
;
Hanqing HE
Author Information
1. 浙江省疾病预防控制中心免疫规划所，杭州 310051
- Keywords:
Varicella;
Breakthrough case;
Associated factors;
Surveillance
- From:
Chinese Journal of Preventive Medicine
2024;58(3):315-324
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To evaluate the epidemiological characteristics and explore the associated factors of breakthrough cases (BC) from Public Health Emergency Events (PHEEs) of varicella in Zhejiang Province from 2019 to 2022.Methods:Data on cases were obtained from the China Information System for Disease Control and Prevention and the PHEEs Reporting Information Database of Varicella in Zhejiang Province. History records were matched through the Zhejiang Provincial Immunization Information System. Descriptive analysis and multiple logistic regression model with a bidirectional stepwise selection method were performed to explore associated factors for BC during 2019-2022.Results:A total of 144 276 varicella cases were reported from 2019 to 2022, with the annual reported incidence of 47.35-82.80 cases per 100 000 population. Among these cases, 109 172 were non-breakthrough cases (NBC, accounting for 75.67%), 34 517 were BC (23.92%), and the rest 587 cases had unclear vaccination history on varicella (0.41%). A total of 214 PHEEs of varicella were reported, of which 99.07% occurred in school settings. The proportion of PHEEs that occurred in high school increased significantly as time went on ( χ2trend=5.742, P=0.017). Multiple logistic regression model which focused on "BC vs. NBC (as the reference)" indicated that the year of onset ( OR=1.585, 95% CI:1.343-1.878), the month of onset (taking January as the reference, OR=2.311-15.652), city (taking Hangzhou as the reference, Jiaxing OR=2.370, Jinhua OR=2.197, Lishui OR=0.134), age ( OR=0.887, 95% CI: 0.826-0.944), PHEEs setting (taking "primary school and below" as the reference, "high school and above" OR=0.516, 95% CI: 0.305-0.897), and the number of rashes ( OR=0.569, 95% CI: 0.458-0.703) were associated factors. Multiple logistic regression model which focused on "two-dose BC vs. one-dose BC (as the reference)" showed that the age of initial vaccination ( OR=0.045, 95% CI: 0.014-0.107), the time interval from onset to the last dose ( OR=0.037, 95% CI: 0.011-0.087) and the age of onset ( OR=20.724, 95% CI: 8.383-72.485) were associated factors. Conclusion:During 2019-2022, the reported high-risk group of varicella in Zhejiang Province has shifted to adolescents and young adults. Although vaccination could not completely prevent the onset of VZV, it could relieve clinical symptoms and delay the age of onset.
