Sentinel Surveillance of Influenza-like Illness Among Children in Zhengzhou from 2017 to 2022

Wang Jingjing; Wang Bohao; Li Ping

doi:10.3969/j.issn.1004-5775.2025.06.021

Abstract：Objective:To analyze the sentinel surveillance results of influenza-like illness(ILI)in children from 2017 to 2022 in Zhengzhou,and explore the epidemic characteristics of influenza in children.Methods:Information of ILI in Zhengzhou Children's Hospital from 2017 to 2022 was collected through the national influenza system,and the data were statistically analyzed.Results:A total of 21 3549 cases of ILI were reported in Zhengzhou Children's Hospital from 2017 to 2022,and the percentage of ILI treatment was 3.51%.The lowest ILI%was 1.55%in 2018,and the highest ILI%was 4.65%in 2021,with statistically significant differences in ILI%between different years and different ages(χ2=14 210.492,P＜0.001).The largest number of ILI reports was in the 0-year-old group,and the least was in the 15-year-old group.A total of 3 645 ILI samples were detected,and 688 were positive for influenza virus.The positive detection rate of influenza virus was 18.88%,and the positive rate of different years had statistical significance(χ2=572.96,P＜0.001).Students(6 years old)had the highest influenza positive rate of 33.64%,and scattered children(0 years old)had the lowest influenza positive rate of 10.17%.The difference between different age groups was statistically significant(χ2=206.99,P＜0.01).From 2017 to 2019,the positive influenza detection showed obvious distribution characteristics in winter and spring,mainly distributed from October to March of the following year,and the influenza A H3N2,new A H1N1 and B Victoria and Yamagata strains alternated.From 2020 to 2022,the positive influenza detection distribution was irregular.There were only A H3N2 and B Victoria series.Conclusion:Influenza virus is widely circulating in children.Affected by the novel coronavirus,ILI monitoring data of children have changed significantly.There are obvious differences in influenza positive typing.There are more influenza positive cases in students.According to the characteristics of the influenza epidemic in children,kindergartens and schools should carry out popular science publicity and strengthen influenza vaccination.