Study on the Epidemiological Characteristics and Influencing Factors of Varicella Breakthrough Cases in Children and Adolescents in Kunshan

Wang Hua; Chen Yingchao; Shen Yang; Ding Xiaofei; Jiang Yuchen

doi:10.3969/j.issn.1001-568X.2025.07.0011

Abstract：OBJECTIVE To master the epidemic characteristics and influencing factors of varicella breakthrough cases in chil-dren and adolescents,and to provide a scientific basis for the in-depth varicella monitoring and prevention and control work and the formulation of prevention and control strategies.METHODS A systematic analysis was conducted using descriptive epidemiological methods on 2 046 cases of varicella breakthrough among children and adolescents in Kunshan from 2018 to 2023,examining the epi-demiological characteristics,vaccination history,and outbreak patterns.RESULTS The average annual incidence of varicella break-through cases was 11.58/105.The proportion of total breakthrough cases increased annually;the incidence rate varied from year to year(χ2=134.834,P＜0.05;χ2=651.011,P＜0.05);the incidence rate of male was higher than female(χ2=46.443,P＜0.05);students were the main group;the peak incidence rate was 6～10 years.There was no significant difference in disease inci-dence between urban and rural areas(χ2=1.405,P＞0.05).The breakthrough rate of one dose of vaccine was significantly higher than that of two doses(χ2=1 039.883,P＜0.05).Varicella breakthrough cases accounted for more than half of the outbreak cases,and the first cases were mostly caused by breakthrough cases.Close contact with varicella cases was a risk factor for breakthrough cases,while receiving two doses of varicella vaccine was a protective factor.CONCLUSION The occurrence and prevalence of break-through varicella cases is a complex public health issue.It is recommended to adopt comprehensive prevention and control measures such as including varicella in the national notifiable infectious disease surveillance,implementing a two-dose immunization strategy,and strengthening monitoring and early warning in high-risk places such as primary and secondary schools.