Epidemiological characteristics of influenza-like illness cases in Hainan Province from 2019-2023
- Author:
WANG Nanlai
;
MA Bin
;
FENG Fangli
- Publication Type:Journal Article
- Keywords:
Hainan Province;
influenza-like illness cases;
epidemic characteristics analysis;
sentinel monitoring
- From:
China Tropical Medicine
2024;24(12):1501-
- CountryChina
- Language:Chinese
-
Abstract:
Objective To analyze the epidemic characteristics of influenza-like illness (ILI) cases in Hainan Province and provide a scientific basis for influenza prevention and control in Hainan Province. Methods The surveillance data of ILI in Hainan Province from 2019 to 2023 were collected through the China Influenza Surveillance Information System and analyzed using descriptive epidemiological methods. Results From 2019 to 2023, the average percentage of visits for influenza-like illness cases (ILI%) in sentinel hospitals was 3.25%. The trend of ILI% varied significantly each year (χ²trend= 5 528.340, P<0.05) and showed marked seasonality, with epidemic peaks occurring from April to June and November to December. The proportion of influenza-like cases was the highest in the 0 to <5 years old group (38.38%, 125 331/326 582), and the lowest in the≥60 years old group (5.81%, 18 975/326 582). Geographically, the central region had the highest ILI% (4.39%, 3 676/83 705), while the western region had the lowest (2.66%, 11 535/433 589), with significant differences between regions (χ2=5 201.647, P<0.05). The dominant strains varied each year; from 2019 to 2020, there was a mixed epidemic of two or more types, including H1N1, and H3 subtypes of influenza A, and Bv lineages. From 2021 to 2023, single subtypes such as H1N1, H3 subtypes, and Bv lineages alternated as dominant strains. The total positive rate of the nucleic acid of the ILI influenza virus from 2019 to 2023 was 13.69%, with variations across different years (χ2=1 263.707, P<0.05), and the dominant epidemic strains varied annually. The positive rate of influenza nucleic acid was the highest in the 5 to < 15-year-old age group, accounting for 21.54% (2 138/9 928). The positive rate of influenza virus nucleic acid was positively correlated with ILI% (r=0.748, P=0.005). Conclusions The overall trend of influenza-like illness in Hainan Province from 2019 to 2023 showed a decline followed by an increase, with high incidence from April to June and November to December, and high susceptibility among the general population, predominantly affecting children and adolescents. The central region had the highest distribution of ILI%, and the western region had the lowest. This suggests that influenza prevention and control should focus on children and adolescents, strengthen influenza surveillance and prevention in schools and other key places, and carry out popular science and education on influenza prevention in key populations and key places before the arrival of the high-incidence season.
- Full text:20251113152106256511.Epidemiological characteristics of influenza-like illness cases in Hainan Province from 2019-2023.pdf
