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Int J Infect Dis
. 2024 Dec 20:107372.
doi: 10.1016/j.ijid.2024.107372. Online ahead of print. Global analysis of influenza epidemic characteristics in the first two seasons after lifting the non-pharmaceutical interventions for COVID-19
Xiaowei Chen 1 , Honghong Chen 2 , Fangfang Tao 3 , Yinzi Chen 3 , Ying Zhou 4 , Jian Cheng 5 , Xiling Wang 6
Affiliations
Objectives: The COVID-19 pandemic significantly disrupted the global influenza seasonal patterns due to non-pharmaceutical interventions. This study aims to describe the influenza seasonal characteristics in the first two seasons after lifting COVID-19 NPIs and assess shifts before, during, and after the pandemic.
Methods: We analyzed country-specific weekly influenza data (2011-2024) from WHO FluNet and collected COVID-19 NPI timing from official announcements. The study was divided into pre-pandemic, pandemic, and post-pandemic phases, estimating epidemic onset, peak week, intensity, and duration by climate zones.
Results: In temperate countries, post-pandemic peak intensity decreased by 8.4%, while duration increased by 1.8 weeks, and onset and peak were delayed by 18.5 and 22.8 weeks. Subtropical countries experienced a 17.2% decrease in peak intensity, a 2.4-week decrease in duration, and delays in onset and peak by 13.5 and 2.3 weeks. Tropical countries had a 10% decrease in peak intensity, a 3-week reduction in duration, and a 6.6-week delay in onset with no significant change in peak time.
Conclusion: Influenza seasonality shifted significantly after the pandemic, with epidemic durations returning to typical patterns but peak intensities remained low. Robust surveillance after an infectious disease pandemic is crucial to inform prevention and control strategies.
Keywords: COVID-19; Influenza; Non-pharmaceutical interventions; Seasonality.
. 2024 Dec 20:107372.
doi: 10.1016/j.ijid.2024.107372. Online ahead of print. Global analysis of influenza epidemic characteristics in the first two seasons after lifting the non-pharmaceutical interventions for COVID-19
Xiaowei Chen 1 , Honghong Chen 2 , Fangfang Tao 3 , Yinzi Chen 3 , Ying Zhou 4 , Jian Cheng 5 , Xiling Wang 6
Affiliations
- PMID: 39710136
- DOI: 10.1016/j.ijid.2024.107372
Objectives: The COVID-19 pandemic significantly disrupted the global influenza seasonal patterns due to non-pharmaceutical interventions. This study aims to describe the influenza seasonal characteristics in the first two seasons after lifting COVID-19 NPIs and assess shifts before, during, and after the pandemic.
Methods: We analyzed country-specific weekly influenza data (2011-2024) from WHO FluNet and collected COVID-19 NPI timing from official announcements. The study was divided into pre-pandemic, pandemic, and post-pandemic phases, estimating epidemic onset, peak week, intensity, and duration by climate zones.
Results: In temperate countries, post-pandemic peak intensity decreased by 8.4%, while duration increased by 1.8 weeks, and onset and peak were delayed by 18.5 and 22.8 weeks. Subtropical countries experienced a 17.2% decrease in peak intensity, a 2.4-week decrease in duration, and delays in onset and peak by 13.5 and 2.3 weeks. Tropical countries had a 10% decrease in peak intensity, a 3-week reduction in duration, and a 6.6-week delay in onset with no significant change in peak time.
Conclusion: Influenza seasonality shifted significantly after the pandemic, with epidemic durations returning to typical patterns but peak intensities remained low. Robust surveillance after an infectious disease pandemic is crucial to inform prevention and control strategies.
Keywords: COVID-19; Influenza; Non-pharmaceutical interventions; Seasonality.