Characteristics of influenza virus epidemic in Yiwu City, Zhejiang Province from 2017 to 2022
10.19428/j.cnki.sjpm.2024.23759
- VernacularTitle:2017—2022年浙江省义乌市流感病毒流行特征分析
- Author:
Buqing CHEN
1
;
Bo CHEN
1
;
Junfang LOU
1
;
Jinhua CHEN
1
Author Information
1. Yiwu Center for Disease Control and Prevention, Yiwu, Zhejiang 322000, China
- Publication Type:Journal Article
- Keywords:
influenza;
influenza-like illness;
virology;
H3N2
- From:
Shanghai Journal of Preventive Medicine
2024;36(7):712-715
- CountryChina
- Language:Chinese
-
Abstract:
ObjectiveTo investigate the epidemiological trends of influenza in Yiwu City, Zhejiang Province from 2017 to 2022, and to provide references for local adjustments to influenza prevention and control strategies. MethodsReal-time fluorescence quantitative PCR was used to detect and type influenza viruses in nasal and pharyngeal swab specimens of the patients with influenza-like illness (ILI). The results were statistically analyzed. ResultsFrom 2017 to 2022, a total of 106 661 ILI cases were reported in Yiwu City, with annual reported cases of 31 273, 33 522, 20 090, 9 965, 3 202, and 8 609, respectively. The majority of ILI cases were in the age group of ≤14 years, accounting for 89.16%. A total of 6 893 specimens were collected and tested, of which 945 were tested positive for influenza virus nucleic acid, with an overall positivity rate of 13.71%. The dominant subtypes were H3N2 and B⁃Victoria, accounting for 40.63% (384/945) and 35.03% (331/945) respectively. The highest positivity rate was in 2019, at 25.19% (265/1 052). The positivity rates significantly decreased in 2020 and 2021, to 5.74% (66/1 149) and 5.77% (75/1 300), respectively. The rate increased in 2022 to 13.85% (180/1 300). The highest proportion of A/H3N2 positivity was in 2017, at 69.14% (168/243). The highest proportion of A/H1N1 positivity was in 2018,at 50.86%(59/116). The highest proportion of B/Victoria positivity was in 2021, at 100.00% (75/75). The highest proportion of B/Yamagata positivity was in 2018, at 5.17% (6/116). ConclusionInfluenza in Yiwu City exhibits obvious seasonal patterns, with two peaks in winter-spring and summer. Dominant strains such as A/H3N2, B/Victoria, and A/H1N1 alternate or co-circulate. During the COVID-19 pandemic, seasonal influenza significantly decreased, and a series of prevention and control measures had a positive effect on influenza prevention and control.