Epidemiological Characteristics of Seasonal Influenza Virus Subtypes in Luoyang Area,Henan Province from 2019 to 2024

ZHAO Le; LI Rui; YANG Guodong; JIANG Tao; HU Hongxia

doi:10.3969/j.issn.1004-437X.2026.10.003

Abstract：Objective To explore the evolutionary trends in the epidemic distribution timeline of different subtypes of seasonal influenza viruses and the age distribution of infected populations,thereby providing more diagnostic bases and epidemiological data for the prevention and control of seasonal influenza.Methods Basic information of influenza patients diagnosed based on influenza virus testing,cases collected from 2019 to 2024 were divided into six different years and while patients were classified into influenza A,influenza B and mixed influenza according to the subtype of infected virus.The chi-square test was used to analyze the relationship between general demographic characteristics and influenza virus.The changes between influenza virus subtypes and the age distribution of the infected population were analyzed.Results A total of 13 123 confirmed influenza patients,8 631 influenza A patients,4 490 influenza B cases and 591 mixed influenza cases were included.The dominant epidemic strains of influenza viruses exhibited alternating prevalence,the epidemic period evolved from winter and spring to winter epidemic,and the peak period was postponed from December to January.Influenza A was good in minors under 20 years of age,the peak was 3 years old,while influenza B was good in people under 40 years old,the main infection peak was 7 years old,another infection peak was oberved in young people around 32 years old.Mixed infections occurred in each year.Conclusion From 2019 to 2024,seasonal influenza viruses in Luoyang area,Henan Province exhibited distinct epidemiological characteristics,including obvious seasonal peaks in winter and spring,significant annual fluctuations,alternating dominant prevalence of influenza A and influenza B,and a certain proportion of mixed infections.These characteristics provide an important basis for formulating scientific and effective influenza prevention and control strategies.