Global patterns and drivers of influenza decline during the COVID-19 pandemic

Autor: Vittoria Colizza, Pierre-Yves Boelle, Chiara Poletto, Olivier Lopez, Francesco Bonacina, Maud Thomas
Přispěvatelé: Surveillance et modélisation des maladies transmissibles [iPLesp] (SUMO), Institut Pierre Louis d'Epidémiologie et de Santé Publique (iPLESP), Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU), Laboratoire de Probabilités, Statistique et Modélisation (LPSM (UMR_8001)), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU), Tokyo Institute of Technology [Tokyo] (TITECH), Department of Molecular Medicine, University of Padova, Padova, Italy, BONACINA, Francesco
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: International Journal of Infectious Diseases
International Journal of Infectious Diseases, 2023, 128, pp.132-139. ⟨10.1101/2022.07.15.22277497⟩
ISSN: 1201-9712
1878-3511
DOI: 10.1101/2022.07.15.22277497⟩
Popis: Influenza circulation declined during the COVID-19 pandemic. The timing and extent of decline and its association with interventions against COVID-19 were described for some regions. Here, we provide a global analysis of the influenza decline between March 2020 and September 2021 and investigate its potential drivers. We computed influenza change by country and trimester relative to the 2014-2019 period using the number of samples in the FluNet database. We used random forests to determine important predictors in a list of 20 covariates including demography, weather, pandemic preparedness, COVID-19 incidence, and COVID-19 pandemic response. With a regression tree we then classified observations according to these predictors. We found that influenza circulation decreased globally, with COVID-19 incidence and pandemic preparedness being the two most important predictors of this decrease. The regression tree showed interpretable groups of observations by country and trimester: Europe and North America clustered together in spring 2020, with limited influenza decline despite strong COVID-19 restrictions; in the period afterwards countries of temperate regions, with high pandemic preparedness, high COVID-19 incidence and stringent social restrictions grouped together having strong influenza decline. Conversely, countries in the tropics, with altogether low pandemic preparedness, low reported COVID-19 incidence and low strength of COVID-19 response showed low influenza decline overall. A final group singled out four “zero-Covid” countries, with the lowest residual influenza levels. The spatiotemporal decline of influenza during the COVID-19 pandemic was global, yet heterogeneous. The sociodemographic context and stage of the COVID-19 pandemic showed non-linear associations with this decline. Zero-Covid countries maintained the lowest levels of reduction with strict border controls and despite close-to-normal social activity. These results suggest that the resurgence of influenza could take equally diverse paths. It also emphasises the importance of influenza reseeding in driving countries’ seasonal influenza epidemics.
Databáze: OpenAIRE
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