Revisiting the link between COVID-19 incidence and infection fatality rate during the first pandemic wave

Several studies found an association between COVID-19 incidence, cumulated over the first pandemic wave, and the risk of death for infected individuals. They attributed this association to hospital overload. We studied this association across the French departments using 82,467 serological samples and a hierarchical Bayesian model with spatial smoothing. In high-incidence areas, we hypothesized that hospital overload would increase infection fatality rate (IFR) without increasing infection hospitalization rate (IHR). The analyses were adjusted for intensive care beds per capita, age of the population, and diabetes prevalence (as a surrogate for obesity). We found that increasing departmental incidence from 3 to 9% rose IFR from 0.42 to 1.14% (difference 0.72%, 95% CI 0.49-1.01%), and IHR from 1.66 to 3.61% (difference 1.94%, 95% CI 1.18-2.80%). An increase in incidence from 6 to 12% in people under 60 was associated with an increased proportion of people over 60 among those infected, from 11.6 to 17.4% (difference 5.8%, 95% CI 2.9-8.8%). Higher incidence increased the risk of death for infected individuals and their risk of hospitalization by the same magnitude. These findings could be explained by a higher age among infected individuals in high-incidence areas, rather by than hospital overload.

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Journal
Scientific Reports
Published
2025-05-05
DOI
https://doi.org/10.1038/s41598-025-99078-6
Citations
3
Primary Topic
COVID-19 epidemiological studies
Type
article
Field-Weighted Citation Impact
4.10
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article

Revisiting the link between COVID-19 incidence and infection fatality rate during the first pandemic wave

Emmanuelle Correia, Fanny Artaud, Adriana Candea, Grégory Pannetier et al.
3 citations
Scientific Reports
COVID-19 epidemiological studies
4.10
article

Revisiting the link between COVID-19 incidence and infection fatality rate during the first pandemic wave

Emmanuelle Correia, Fanny Artaud, Adriana Candea, Grégory Pannetier, Sofiane Kab, Hélène Blanché, Cécile Zaros, Karim ASSAAD, Anass Ritmi, Pierre‐Yves Ancel, Marie‐Noëlle Dufourg, Alpha Amadou Barry, Fabien Szabo de Edelenyi, Mélody Enguix, Emmanuel Wiernik, Läétitia Ninove, Marcel Goldberg, Hélène Espérou, Céline Dorival, Souand Mohamed Ali, Mélanie Deschasaux, Jean-Christophe Beaudoin, Cindy J. Lai, Laetitia Marchand‐Martin, Stéphane Le-Got, Valérie Deldrève, Sandrine Couffin-Cadièrgues, Toscane Fourié, Nathalie Druesne‐Pecollo, Serge Herçberg, Paola Mariela Saba Villarroel, Jean‐François Deleuze, Mireille Pellicer, Thierry Siméon, Céline Ribet, Boris Pastorino, Jean-Marc Sébaoun, Walid Ghosn, Elodie Lordmi, Jean‐Marie Gagliolo, Abdenour Amroun, Morgan Seston, Delphine Rahib, Younes Esseddik, Roselyn Gomes-Rima, Xavier Thierry, Nadège Senina, Clovis Lusivika‐Nzinga, Sophie de Visme, Nazlı Ayhan, Valérie Benhammou, Marie Zins, Ouissam Ouili, Pascale Gerbouin-Rérolle, C Laplanche, Karen Milcent, Lyan Hoang, Stéphane Priet, Paul Moulaire, Adeline Renuy, Liza Belhadji, Nathanaël Lapidus, Isabelle Goderel, Laëtitia Gressin, Olivier Robineau, Benjamin Glémain, Xavier de Lamballerie, Fabrice Carrat, Marie-Aline Charles, Bertrand Geay, Julien Allègre, Jérôme Nicol, Gianluca Severi, Nathalie Lydié, Mathilde Touvier
article en
3 citations

Abstract

Several studies found an association between COVID-19 incidence, cumulated over the first pandemic wave, and the risk of death for infected individuals. They attributed this association to hospital overload. We studied this association across the French departments using 82,467 serological samples and a hierarchical Bayesian model with spatial smoothing. In high-incidence areas, we hypothesized that hospital overload would increase infection fatality rate (IFR) without increasing infection hospitalization rate (IHR). The analyses were adjusted for intensive care beds per capita, age of the population, and diabetes prevalence (as a surrogate for obesity). We found that increasing departmental incidence from 3 to 9% rose IFR from 0.42 to 1.14% (difference 0.72%, 95% CI 0.49-1.01%), and IHR from 1.66 to 3.61% (difference 1.94%, 95% CI 1.18-2.80%). An increase in incidence from 6 to 12% in people under 60 was associated with an increased proportion of people over 60 among those infected, from 11.6 to 17.4% (difference 5.8%, 95% CI 2.9-8.8%). Higher incidence increased the risk of death for infected individuals and their risk of hospitalization by the same magnitude. These findings could be explained by a higher age among infected individuals in high-incidence areas, rather by than hospital overload.

Scientific ReportsVol. 15(1)
Inserm (FR), Université de Versailles Saint-Quentin-en-Yvelines (FR), Université Paris Cité (FR), Université Paris-Saclay (FR), Fondation Jean Dausset-CEPH (FR), Sorbonne Université (FR), Méditerranée Infection Foundation (FR), Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (FR), Université Sorbonne Paris Nord (FR), Sorbonne Paris Cité (FR), Santé Publique France (FR), Assistance Publique – Hôpitaux de Paris (FR), Centre de recherche en Epidémiologie et Santé des Populations (FR), Centre d'Épidémiologie sur les Causes Médicales de Décès (FR), Institut Pierre Louis d‘Épidémiologie et de Santé Publique (FR), Equipe de Recherche en Epidémiologie Nutritionnelle (FR), Institut de Recherche pour le Développement (FR), Centre de Recherche Épidémiologie et Statistique (FR), Cohortes épidémiologiques en population (FR), University of Florence (IT)
Good health and well-being
Openalex Percentile: Top 7%
COVID-19 epidemiological studies
4.10
DOIOpen Access PDFOpenAlex
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