20172022年浙江省义乌市流感病毒流行特征分析

Characteristics of influenza virus epidemic in Yiwu City, Zhejiang Province from 2017 to 2022

  • 摘要:
    目的 了解浙江省义乌市2017—2022年流感样病例(ILI)活动水平和流行动态,为当地调整流感防控策略提供参考。
    方法 采用实时荧光定量聚合酶链反应(PCR)法对ILI鼻咽拭子标本进行流感病毒分型检测,对结果进行统计和分析。
    结果 2017—2022年义乌市共报告ILI106 661例,年报告病例数分别为31 273、33 522、20 090、9 965、3 202和8 609例,以≤14岁人群为主,占89.16%。共采集检测ILI标本6 893份,流感病毒核酸阳性945份,总阳性率为13.71%,以H3N2、B⁃Victoria为主,占比分别为40.63%(384/945)、35.03%(331/945)。阳性率以2019年最高,为25.19%(265/1 052);2020、2021年阳性率显著下降,分别为5.74%(66/1 149)、5.77%(75/1 300);2022年有所回升,为13.85%(180/1 300)。H3N2阳性占比以2017年最高,占69.14%(168/243);H1N1阳性占比以2018年最高,50.86%(59/116);B⁃Victoria阳性占比以2021年最高,占100.00%(75/75);B⁃Yamagata阳性占比以2018年最高,占5.17%(6/116)。
    结论 义乌市ILI季节性流行特征较为明显,呈现冬春、夏两峰型,H3N2、B⁃Victoria、H1N1等优势毒株呈交替或混合流行。新型冠状病毒感染大流行期间季节性ILI显著减少,采取的一系列防控措施对ILI的防控有积极的作用。

     

    Abstract:
    Objective To 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.
    Methods Real-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.
    Results From 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).
    Conclusion Influenza 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.

     

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