Epidemiological characteristics of influenza-like illness outbreaks in Guangxi, 2018−2022

  Objective  To understand the epidemiological characteristics and influencing factors of influenza-like illness (ILI) outbreaks in Guangxi Zhuang autonomous region from 2018 to 2022, and provide evidence for the prevention and control of influenza.

  Methods  The ILI outbreaks data and etiological detection results in Guangxi from 2018 to 2022 were collected from “China Influenza Surveillance Information System” and “Public Health Emergency Reporting and Management Information System”. A descriptive analysis method was used to analyze the influenza data.

  Results  From 2018 to 2022, a total of 474 ILI outbreaks were reported in Guangxi, involving 40 996 cases. The annual outbreak showed obvious seasonality with peak between November and December; ILI outbreaks mainly occurred in primary and secondary schools, accounting for 90.51% (429/474). Most cases were aged 5−14 years, accounting for 84.55% (34 663/40 996) of the total reported cases. From 2018 to 2022, all types of influenza viruses were detected, and more than two types of influenza viruses spread every year. The predominant strains causing the outbreaks showed an alternating trend of influenza A (H1N1), A (H3N2) viruses and influenza B virus Victoria linage.

  Conclusion  ILI outbreaks mainly occurred in primary and secondary schools in Guangxi, and had obvious seasonality. The predominant strains of influenza viruses altered frequently, and continuous surveillance should be carried out to understand the activities of influenza viruses in time.