RESUMO
@#Abstract: Objective To analyze the epidemic characteristics and influencing factors of school influenza-like cases in 2011-2022 in Nanchang, so as to provide reference for the prevention and control of school influenza outbreaks. Methods The epidemiological relevant data of school influenza-like cases from 2011 to 2022 in Nanchang and the pathogen test results of respiratory tract samples were collected for epidemiological and etiology analysis. Results From 2011 to 2022, a total of 142 influenza-like cases were reported in schools in Nanchang, with a cumulative morbidity of 2 880 cases and a morbidity rate of 1.89%. A total of 1 263 samples were collected, with an overall positive influenza nucleic acid detection rate of 58.91%. The highest proportion of outbreaks occurred in 2017-2019, while the lowest incidence was in 2011-2013. Outbreaks mainly occurred from November to March of the following year (accounting for 79.58%), presenting obvious seasonal characteristics. The distribution was mainly in primary schools, accounting for 70.42% (100/142) of all outbreaks. From 2011 to 2022, all types of influenza viruses were tested, and more than 2 types of influenza viruses were prevalent each year. The dominant strains alternated between influenza A H1N1, influenza A H3N2 and Victoria lineages of type B influenza viruses. From 2011 to 2019, the influenza epidemic in schools in Nanchang showed a continuous upward trend. During COVID-19 in 2020-2022, Nanchang adopted a variety of non-drug prevention and control measures for COVID-19, and both the number of influenza epidemics in various schools and the number of influenza virus nucleic acid positive cases decreased. The average number of classes involved in the epidemic was (3±2), and the average duration of the epidemic was (8±4) days. Conclusions The outbreaks of influenza-like illness in Nanchang schools is highly prevalent in winter and spring, , with urban primary schools being the high incidence locations. Non-drug prevention and control measures for COVID-19 have an impact on the epidemic trend of influenza, so the continuous monitoring of the school influenza virus activities and improving the timeliness of the report will be conducive to the rapid control of the epidemic.