Epidemiological characteristics of norovirus infection in Lin’an District of Hangzhou City from 2012 to 2020

ObjectiveTo determine the epidemiological characteristics of norovirus infections in Lin’an District， Hangzhou City from 2012 to 2020， and provide scientific evidence for improving preventive and control measures.MethodsDescriptive epidemiological methods were used to characterize the epidemic and conduct statistical analysis to determine related factors.ResultsA total of 37 clustered outbreaks of norovirus infection were reported in Lin’an District of Hangzhou from 2012 to 2020， including 8 outbreaks in kindergartens， 15 ones in elementary schools， 8 ones in middle and high schools， 2 ones in universities， and 4 other ones. The total number of cases with norovirus infection was 1 194， with the average attack rate of 3.76%. The incidence of norovirus was higher in winter and spring. It was also higher in urban areas， followed by suburban and mountainous areas neighbored to traffic lines. Moreover， attack rates differed significantly by transmission routes， including mixed contact and aerosol transmission， contact transmission， food-borne transmission， and water-borne transmission （χ2=186.91，P