Abstract: Objective To analyze the epidemiological feature of influenza in Yantian District of Shenzhen City for estimation of the epidemic trend and evidence to develop prevention and control strategies for influenza. Methods The data pertinent to surveillance over the influenza-like cases (ILI),outbreak of influenza in areas under the administration of Yantian District as well as the findings of pathogen detection were collected from 2016 to 2020,and statistically analyzed. Results Totally,1 563 ILI cases were reported from the sentinel hospitals in Yantian District of Shenzhen City from 2016 to 2020,of which 898 were males and 665 females. The patients aged from zero to 15 years,accounting for 67. 31%(1 052 / 1 563) of the reported cases. 1 563 samples of ILI were obtained from 2016 to 2020,in which 302 samples were identified positive, with a total positive rate being 19. 32%. Between 2016 and 2020,the positive rate of ILI was 23. 79%,21. 39%,16. 23%, 31. 11% and 2. 42%,respectively,and had statistical difference among years( χ2 = 87. 829,P<0. 05). The dominant influenza subtypes were associated with influenza A(H1N1)pdm09 and B (Victoria) in 2016,A(H3N2) and A(H1N1) pdm09 in 2017,A(H1N1)pdm09 and B ( Victoria) in 2018,A( H1N1) pdm09,A( H3N2) and B ( Victoria) in 2019. Only A (H3N2) was detected in 2020. Eighty-two outbreaks of ILI were reported from 2016 to 2020. A total of 451 samples were collected,in which 314 were positive. The positive rate was 69. 62%. The outbreak occurred primarily in primary schools and secondary schools. Conclusion Our results suggest that the flu subtypes are alternately prevalent in different surveillance years in Yantian District. The population aged 0~ 15 years are most affected,and schools should be intensively monitored in following prevention and control efforts. In addition,the flu vaccination should be expanded in key population,and the surveillance should be strengthened in schools.

Key words: Influenza, Surveillance, Epidemiological feature