tetano
Editor, Senior Moderator
Hum Vaccin Immunother
. 2026 Dec 31;22(1):2675787.
doi: 10.1080/21645515.2026.2675787. Epub 2026 May 20.
Epidemiological and virological characteristics of influenza in Zhejiang Province, China: A 15-year surveillance study
Jialie Jin[SUP] 1 [/SUP], Zhao Yu[SUP] 1 [/SUP], Ying Zhu[SUP] 2 [/SUP], Yanli Cao[SUP] 1 [/SUP], Hangjie Zhang[SUP] 1 [/SUP], Xiaoxiao Wang[SUP] 1 [/SUP], Jimin Sun[SUP] 1 [/SUP]
Affiliations
Understanding the complex epidemiological and virological characteristics of influenza is critical for optimizing seasonal influenza control and prevention programs; to this end, we analyzed the influenza and influenza-like illness (ILI) cases reported in Zhejiang Province from 2010 to 2025. Annual average percentage (AAP) approach was used to estimate the influenza seasonal epidemic onset and duration. Generalized additive model (GAM) was used to explore the nonlinear relationship between age and the positive rate of influenza. Spearman correlation analysis was performed to assess the association between weekly ILI% and influenza positivity rate. A total of 5,853,160 influenza cases and 8,732,124 ILI cases were reported. The ILI% ranged from 2.49 to 6.84% (mean: 4.37%), with the lowest level in 2010-2011 and the highest in 2023-2024. The median duration of seasonal influenza epidemics was 4.59 months (IQR: 2.84-5.88). Children aged 5~14 y had the highest influenza positivity rate (41.73%). Influenza virus subtypes/lineages varied significantly by seasons and age groups. A/H3N2 was the predominant pathogen during the summer seasons and the positivity rate of A/H3N2 was much higher than that of other subtypes/lineages among individuals aged ≤60 y. ILI% was positively correlated with influenza positivity during 2010-2025 except in the 2020-2021 surveillance year. This study revealed significant variations in seasonal epidemic period and age-specific distributions across influenza subtypes/lineages, as well as a marked disruption of influenza activity due to the COVID-19 pandemic.
Keywords: Influenza; epidemiological; influenza-like illness; surveillance; virological.
. 2026 Dec 31;22(1):2675787.
doi: 10.1080/21645515.2026.2675787. Epub 2026 May 20.
Epidemiological and virological characteristics of influenza in Zhejiang Province, China: A 15-year surveillance study
Jialie Jin[SUP] 1 [/SUP], Zhao Yu[SUP] 1 [/SUP], Ying Zhu[SUP] 2 [/SUP], Yanli Cao[SUP] 1 [/SUP], Hangjie Zhang[SUP] 1 [/SUP], Xiaoxiao Wang[SUP] 1 [/SUP], Jimin Sun[SUP] 1 [/SUP]
Affiliations
- PMID: 42157696
- DOI: 10.1080/21645515.2026.2675787
Understanding the complex epidemiological and virological characteristics of influenza is critical for optimizing seasonal influenza control and prevention programs; to this end, we analyzed the influenza and influenza-like illness (ILI) cases reported in Zhejiang Province from 2010 to 2025. Annual average percentage (AAP) approach was used to estimate the influenza seasonal epidemic onset and duration. Generalized additive model (GAM) was used to explore the nonlinear relationship between age and the positive rate of influenza. Spearman correlation analysis was performed to assess the association between weekly ILI% and influenza positivity rate. A total of 5,853,160 influenza cases and 8,732,124 ILI cases were reported. The ILI% ranged from 2.49 to 6.84% (mean: 4.37%), with the lowest level in 2010-2011 and the highest in 2023-2024. The median duration of seasonal influenza epidemics was 4.59 months (IQR: 2.84-5.88). Children aged 5~14 y had the highest influenza positivity rate (41.73%). Influenza virus subtypes/lineages varied significantly by seasons and age groups. A/H3N2 was the predominant pathogen during the summer seasons and the positivity rate of A/H3N2 was much higher than that of other subtypes/lineages among individuals aged ≤60 y. ILI% was positively correlated with influenza positivity during 2010-2025 except in the 2020-2021 surveillance year. This study revealed significant variations in seasonal epidemic period and age-specific distributions across influenza subtypes/lineages, as well as a marked disruption of influenza activity due to the COVID-19 pandemic.
Keywords: Influenza; epidemiological; influenza-like illness; surveillance; virological.