Epidemiological characteristics of varicella epidemic situation at schools and kindergartens in Fengxian District of Shanghai during 2012-2018 / 中国学校卫生

ABSTRACT

Objective@#To analyze the epidemiological characteristics of varicella epidemic situation at schools and kindergartens in Fengxian district of Shanghai during 2012-2018, and to provide evidence for developing control and prevention strategies.@*Methods@#Data of varicella epidemic situation at schools and kindergartens and varicella cases were analyzed by descriptive methods. The rates were compared with chi-square test.@*Results@#A total of 6 727 varicella cases were reported in Fengxian during 2012-2018, for an incidence of 85.34 per 100 000 population. Totally 66 varicella epidemic outbreaks and public health emergencies caused by varicella were reported, which involved 741 varicella cases. Among them, 426 were breakthrough cases (57.49%). The average interval time of breakthrough cases were (6.78±2.79)years, and the incidence was more concentrated in the 3-9 years after vaccination with varicella vaccine. Most breakthrough cases appeared 5 years past vaccination. The peak time of varicella was from April to June and from October to December. Most of cases were in the 5-11 year-old group and 15-17 year-old group. The cases in males was higher than in females. Kindergarten childcare and primary school children were at high risk of varicella. Timeliness of reporting was positively correlated with the duration of the varicella epidemic situation( r =0.52， P <0.05).@*Conclusion@#Most varicella epidemic situation in Fengxian district of Shanghai occued in primary schools during autumn and winter, and most of the varicella cases were breakthrough cases. Emergency vaccination of varicella vaccine can effectively control the spread of the epidemic. It is suggested to increase the publicity of the immunization program of 2 doses of varicella vaccine and raise the awareness of varicella vaccination of children’s parents.