Monitoring results and epidemic characteristics of influenza virus from 2016 to 2019 in Wuxi City of Jiangsu Province

Objective To analyze the epidemic status of influenza virus from 2016 to 2019 in Wuxi City of Jiangsu Province. Methods Monitoring data of influenza etiology from 2016 to 2019 in Wuxi City of Jiangsu Province was analyzed. Results From 2016 to 2019, a total of 98 591 influenza-like illnesses(ILI)were reported in influenza surveillance sentinel hospitals in Wuxi City in Jiangsu Province, with an average of 2.53% of ILI visits. ILI in children and adolescents accounted for 93.91% of the total influenza cases. A total of 10 409 ILI samples were detected in influenza network laboratory, 2 041 cases were positive for influenza virus, and the positive rate of influenza virus was 19.61%. The distribution characteristics of influenza from 2016 to 2019 in Wuxi City were manifested as winter-spring peak and summer peak. The dominant types of influenza virus in winter and spring of 2016 and 2019 were novel influenza A(H1N1)virus and type B Victoria. The dominant types of influenza viruses in the winter and spring of 2017 were seasonal H3 and type B Victoria, and the peak influenza strains in summer were seasonal H3. The prevalent virus types of influenza in winter and spring of 2018 were type B Yamagata and H1N1. Conclusion From 2016 to 2019, the influenza in Wuxi City is prevalent in winter, spring and summer. We should pay attention to the prevention and control work before the epidemic season comes, and strengthen the monitoring of influenza.