BACKGROUND

Schools are special and important places where susceptible groups of infectious diseases congregate, providing conditions for infectious disease outbreaks. A retrospective analysis of school outbreaks was conducted to explore the epidemiological characteristics of school outbreaks in Zhejiang Province, China.

METHODS

Data on school infectious disease outbreaks reported in Zhejiang Province from 2013 to 2021 were collected. The characteristics of the temporal and spatial distributions, attack rates, identification durations, outbreak durations and influencing factors were studied using descriptive epidemiological methods.

RESULTS

A total of 1248 school outbreaks of 20 infectious causes were reported, for an overall attack rate of 2.97%. Among intestinal and respiratory infections, norovirus acute gastroenteritis and varicella, respectively, were the most common causes. May and December presented the greatest number of causes of school outbreaks, whereas November to January presented the peak number of school outbreaks. The three causes of outbreaks with the highest attack rates were herpeticangina (7.76%), influenza-like illness (7.48%), and influenza (6.37%) outbreaks. The three most common causes with the longest median identification duration and median outbreak duration were tuberculosis, Mycoplasma pneumoniae, and mumps. Kindergartens (5.54%), by school closures (3.44%), and rural schools (4.02%) presented higher attack rates, whereas reporting outbreaks within two days yielded a lower attack rate (2.09%). The median duration of outbreaks in kindergartens (4.00 days), by school closures (7.00 days), and reporting outbreaks within two days (3.00 days) was shorter, whereas that in rural schools was longer (10.50 days).

CONCLUSION

Kindergartens and rural schools are the key units for preventing and controlling school outbreaks. May and November-January should receive more attention. Timely reporting and school closures could be implemented to reduce the attack rate, outbreak duration, and impact of infectious diseases on students' health.