Analysis of the influenza surveillance in Beijing during 2015-2020 influenza seasons
10.3760/cma.j.cn112866-20200803-00220
- VernacularTitle:北京市2015—2020年流感流行季流感样病例和流感病原学分析
- Author:
Chunna MA
1
;
Shuangsheng WU
;
Li ZHANG
;
Yi ZHANG
;
Ying SUN
;
Wei DUAN
;
Peng YANG
;
Quanyi WANG
Author Information
1. 北京市疾病预防控制中心 北京市预防医学研究中心传染病地方病控制所 100013
- Keywords:
Influenza;
Influenza-like illness;
Subtypes;
Surveillance
- From:
Chinese Journal of Experimental and Clinical Virology
2021;35(1):44-48
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To analyze epidemiological characteristics of influenza in Beijing during 2015—2020 influenza seasons.Methods:Weekly numbers of cases with influenza-like illness and weekly data of virologic surveillance was used to analyze epidemic trend and characteristics of influenza.Results:From June 26, 2015 to June 28, 2020, influenza-like illness (ILI) was 1.58%. A total of 49868 pharyngeal swab samples were collected from ILI cases, and positive rate of influenza virus nucleic acid was 16.32% by real-time PCR. Of these positive samples, 40.89% (6 474) were A(H3N2), 27.86% (4 410) were A (H3N2), 20.78% (3 290) were B/Victoria lineage, and 10.09%(1597) were B/Yamagata lineage. There were correlation between ILI and positive rate of influenza virus ( r=0.796, P<0.001), and ILI percentage and positive rate were also correlated ( r=0.808, P<0.001). The active duration in 2018—2018, 2018—2019 influenza seasons were longer. Weekly numbers of influenza-like illness cases of 2017—2018, 2018—2019 influenza seasons were higher (49 628 and 71 555), peak value of positive rate in the above seasons was higher (58.51% and 57.08%). Conclusions:The epidemic characteristics of influenza during 2015—2020 years was in accordance with the temperate regions of the northern hemisphere. There were longer active period and higher epidemic level in 2017—2018, 2018—2019 influenza seasons. The dominant influenza virus subtypes varied in the different seasons.
