Immunity debt for seasonal influenza after the COVID-19 pandemic and as a result of non-pharmaceutical interventions: an ecological analysis and cohort study

<p>Non-pharmaceutical interventions (NPIs) during the COVID-19 pandemic significantly reduced influenza transmission. This study explores the hypothesis of "immunity debt" which suggests increased vulnerability to influenza following reduced exposure during the pandemic. We analyzed...

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Main Authors: Chen, L, Guo, Y, López-Güell, K, Ma, J, Dong, Y, Xie, J, Prieto Alhambra, D
Format: Journal article
Language:English
Published: Wiley 2025
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author Chen, L
Guo, Y
López-Güell, K
Ma, J
Dong, Y
Xie, J
Prieto Alhambra, D
author_facet Chen, L
Guo, Y
López-Güell, K
Ma, J
Dong, Y
Xie, J
Prieto Alhambra, D
author_sort Chen, L
collection OXFORD
description <p>Non-pharmaceutical interventions (NPIs) during the COVID-19 pandemic significantly reduced influenza transmission. This study explores the hypothesis of "immunity debt" which suggests increased vulnerability to influenza following reduced exposure during the pandemic. We analyzed World Health Organization aggregated data in influenza from 116 countries and its association with NPI intensity as measured by the COVID-19 Stringency Index. Where individual-level data available (France, the United Kingdom, Spain, Italy, Belgium, and Romania), we replicated our analyses of influenza monthly rate in six Europe countries (France, the United Kingdom, Spain, Italy, Belgium, and Romania). Our results indicate globally a 46.3% (95%CI: 15.79 to 70.78%) reduction in influenza cases during COVID-19 restrictions in winter season, followed by a 131.7% (95%CI: 34.95 to 255.78%) increase in the first post-relaxation winter and a 161.2% (95%CI: 31.88 to 382.16%) increase in the summer as compared to the predicted level based on historical influenza epidemic trends. In addition, a positive association between the Stringency Index and post-relaxation influenza surge was observed globally (R² = 0.14-0.17) and replicated regionally. Our findings support the population immunity debt hypothesis for influenza and call for proactive preparations against its consequences in future pandemics.</p>
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spelling oxford-uuid:7e8e37ad-3beb-4200-9dc2-92adecea17ca2025-01-24T10:36:00ZImmunity debt for seasonal influenza after the COVID-19 pandemic and as a result of non-pharmaceutical interventions: an ecological analysis and cohort studyJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:7e8e37ad-3beb-4200-9dc2-92adecea17caEnglishSymplectic ElementsWiley2025Chen, LGuo, YLópez-Güell, KMa, JDong, YXie, JPrieto Alhambra, D<p>Non-pharmaceutical interventions (NPIs) during the COVID-19 pandemic significantly reduced influenza transmission. This study explores the hypothesis of "immunity debt" which suggests increased vulnerability to influenza following reduced exposure during the pandemic. We analyzed World Health Organization aggregated data in influenza from 116 countries and its association with NPI intensity as measured by the COVID-19 Stringency Index. Where individual-level data available (France, the United Kingdom, Spain, Italy, Belgium, and Romania), we replicated our analyses of influenza monthly rate in six Europe countries (France, the United Kingdom, Spain, Italy, Belgium, and Romania). Our results indicate globally a 46.3% (95%CI: 15.79 to 70.78%) reduction in influenza cases during COVID-19 restrictions in winter season, followed by a 131.7% (95%CI: 34.95 to 255.78%) increase in the first post-relaxation winter and a 161.2% (95%CI: 31.88 to 382.16%) increase in the summer as compared to the predicted level based on historical influenza epidemic trends. In addition, a positive association between the Stringency Index and post-relaxation influenza surge was observed globally (R² = 0.14-0.17) and replicated regionally. Our findings support the population immunity debt hypothesis for influenza and call for proactive preparations against its consequences in future pandemics.</p>
spellingShingle Chen, L
Guo, Y
López-Güell, K
Ma, J
Dong, Y
Xie, J
Prieto Alhambra, D
Immunity debt for seasonal influenza after the COVID-19 pandemic and as a result of non-pharmaceutical interventions: an ecological analysis and cohort study
title Immunity debt for seasonal influenza after the COVID-19 pandemic and as a result of non-pharmaceutical interventions: an ecological analysis and cohort study
title_full Immunity debt for seasonal influenza after the COVID-19 pandemic and as a result of non-pharmaceutical interventions: an ecological analysis and cohort study
title_fullStr Immunity debt for seasonal influenza after the COVID-19 pandemic and as a result of non-pharmaceutical interventions: an ecological analysis and cohort study
title_full_unstemmed Immunity debt for seasonal influenza after the COVID-19 pandemic and as a result of non-pharmaceutical interventions: an ecological analysis and cohort study
title_short Immunity debt for seasonal influenza after the COVID-19 pandemic and as a result of non-pharmaceutical interventions: an ecological analysis and cohort study
title_sort immunity debt for seasonal influenza after the covid 19 pandemic and as a result of non pharmaceutical interventions an ecological analysis and cohort study
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