Analysis on the epidemiological characteristics of varicella and breakthrough case from 2014 to 2022 in Qingyang City

We analyze the epidemiological characteristics of varicella and breakthrough cases in Qing Yang City, Gansu Province, and provide a basis for the formulation of varicella prevention and control policies. Varicella and breakthrough cases, public health emergency events in Qing Yang City during 2014–2022 were obtained from the China Disease Prevention and Control information System, and the immunization history of the cases were collected from the Gansu Provincial Immunization Planning Information System, descriptive epidemiological analysis of the obtained information was then performed. A total of 6961 cases of varicella were reported in Qing Yang City from 2014 to 2022, yielding an annual incidence of 36.99 cases per 100 000 population. The incidence increased from 19.74/100,000 in 2014 to 35.97/100,000 in 2022; the incidence peaks were observed from May to July and from November to January of the next year. The reported incidence is higher in males (37.70/100,000) than in females (31.54/100,000), and the main age groups were 4 ~ 6 years old (241.98/100,000), 7 ~ 9 years old (142.39/100,000), 10 ~ 14 years old (101.99/100,000). There were 1975 breakthrough cases, accounting for 28.4% of the total reported cases; the majority of patients were students, children in nursery care and scattered children; a total of 10 outbreaks of varicella were reported in primary schools (40.0%), secondary schools (30.0%), kindergartens (20.0%) and high schools (10.0%). The incidence of varicella showed an increasing trend, children and students are high-risk population. It is suggested that varicella vaccine should be included into the immunization program, and the vaccination rate of two-dose of varicella vaccine should be increased for age-eligible children, and varicella surveillance should be strengthened.