Analysis on epidemiological characteristics of influenza and genetic characteristics of influenza virus in 2023-2024 surveillance year in Shandong Province
10.3760/cma.j.cn112338-20240906-00560
- VernacularTitle:2023-2024监测年度山东省流感流行特征及流感病毒基因特征分析
- Author:
Yujie HE
1
;
Lin SUN
;
Shaoxia SONG
;
Shu ZHANG
;
Julong WU
;
Yang DONG
;
Zhong LI
;
Xianjun WANG
;
Zengqiang KOU
;
Ti LIU
Author Information
1. 山东省疾病预防控制中心/山东省预防医学研究院/山东省传染病智慧化监测预警和防控重点实验室，济南 250014
- Publication Type:Journal Article
- Keywords:
Influenza;
Epidemiological characteristic;
Genetic characteristic;
Surveillance
- From:
Chinese Journal of Epidemiology
2025;46(3):430-439
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To analyze the epidemiological, etiological and genetic characteristics of influenza virus in Shandong Province during 2023-2024.Methods:The surveillance data of influenza-like illness (ILI) in sentinel hospitals in Shandong from 2023 to 2024 were collected and analyzed. The isolated influenza strains with hemagglutination titers ≥8 were selected for antigenicity analysis, drug susceptibility test, gene sequencing and evolutionary analysis.Results:From 2023 to 2024, the positive rate of influenza virus in Shandong was 8.51% (23 663/277 995), the highest positive rate was in the age group of 5-14 years (15.78%, 6 073/38 478), and the highest positive rate was in the 49 th week (35.86%, 2 264/6 313). Both antigenicity analysis and evolutionary analysis showed that the A(H1N1)pdm09 subtype and B(Victoria) strain had good matching effect and close evolutionary distance with the 2023-2024 surveillance year vaccine strain. The A(H3N2) subtype strain did not have a high matching effect with the 2023-2024 vaccine strain and had a long evolutionary distance, but had a close evolutionary distance with the 2024-2025 vaccine strain. Drug susceptibility test showed that oseltamivir sensitivity of influenza A(H1N1)pdm09 strain decreased greatly, and the amino acid site mutation of neuraminidase was H275Y. Conclusions:In the 2023-2024 surveillance year, the peak of influenza virus epidemic in Shandong was mainly occurred in winter and spring, and the age group of 5-14 years was the focus of prevention and control. The dominant strain was subtype A(H3N2), which had poor matching effect with the vaccine strain in the 2023-2024 surveillance year. One A(H1N1)pdm09 resistant strain was found in the drug resistance monitoring work. Follow-up prevention and control work should be strengthen the surveillance for the epidemiological characteristics, genetic variation and drug resistance of influenza viruses, timely understand the epidemic trend and mutation of influenza viruses, timely discover drug-resistant strains of influenza viruses, promote influenza vaccination, and improve of influenza prevention and control.
