Analysis of influenza prevalence among children in Jinshan District of Shanghai from 2010 to 2019 / 上海预防医学

ABSTRACT

Objective To analyze the epidemic characteristics of influenza in children in Jinshan District of Shanghai，so as to provide scientific basis for prevention and control of influenza in children. Methods We analyzed the surveillance data as well as the results of virus isolation and identification in children with influenza-like illness （ILI） in Jinshan District of Shanghai from January 2010 to December 2019. Results There were two annual epidemic peaks in 2010， 2016， 2017 and 2018， one annual epidemic peak in winter and spring in 2011 and 2013， and two annual epidemic peaks in 2012， 2014， 2015 and 2019. A total of 3 859 ILI cases were collected in the past 10 years， and 848 positive virus strains were isolated， with a positive rate of 21.97%. Among them， 371 were seasonal H3N2， 163 were new H1N1， 314 were type B（among them， 226 were yamagata and 88 were victoria）. The positive rates of influenza virus in different children groups were 0.88% in scattered children， 6.76% in kindergarten children， and 14.33% in students， respectively （P= 0.001）. Conclusion From January 2010 to December 2019， seasonal H3N2 was the predominant virus strain in children influenza epidemic in Jinshan District of Shanghai. The influenza epidemic shows a strong seasonal feature with double peaks in winter/spring， summer or autumn. The positive rate of influenza virus in middle school students is the highest in different age groups， followed by kindergarten children.