tetano
Editor, Senior Moderator
Clin Infect Dis
. 2026 Nov 11:ciag648.
doi: 10.1093/cid/ciag648. Online ahead of print.
Nicolas de Prost 1 2 3 , Pierre Bay 1 2 3 , Marie Le Goff 1 2 3 , Sébastien Préau 4 5 , Aurélie Guigon 6 , François M Beloncle 7 , Caroline Lefeuvre 8 , Anaïs Dartevel 9 , Sylvie Larrat 10 , Rémi Coudroy 11 12 , Luc Deroche 13 14 , Cédric Darreau 15 , Jean Thomin 16 , Cécile Aubron 17 , Adissa Tran 18 , Fabrice Uhel 19 20 , Quentin Le Hingrat 21 , Fabienne Tamion 22 , Alice Moisan 23 , Antoine Guillon 24 , Lynda Handala 25 , Bertrand Souweine 26 , Cecile Henquell 27 , Kada Klouche 28 29 , Edouard Tuaillon 30 31 , Charles Damoisel 32 , Anne-Marie Roque-Afonso 33 , Elyanne Gault 34 , Pierre Cappy 3 35 , Alexandre Soulier 3 35 , Jean-Michel Pawlotsky 3 35 , Frédéric Lemoine 36 37 , Marie-Anne Rameix-Welti 38 39 , Etienne Audureau 40 41 , Slim Fourati 3 35 ; SEVARVIR investigators
Collaborators, Affiliations Expand
Background: Intense influenza activity has been reported alongside the emergence of influenza A(H3N2) subclade K. While epidemiological studies have reported heterogeneous findings regarding public health impact, data remain lacking on its impact on clinical phenotype of people requiring intensive care unit (ICU) admission.
Methods: Prospective, multicenter, observational SEVARVIR cohort study including people admitted in 42 French ICUs with laboratory-confirmed influenza infection during the 2024-2025 and 2025-2026 seasons. Primary end point was day-28 mortality.
Results: Seven hundred twenty-six people were admitted for influenza in 2024-2025 (n = 360) and 2025-2026 (n = 366). In 2025-2026, influenza subtype was available for 265 people; 49% (n = 129) had A(H1N1)pdm09 and 51% (n = 136) had A(H3N2) subtype infection. Among the 40 people with A(H3N2) infection for whom whole-genome sequencing was available, 33 (82.5%) belonged to subclade K. In multivariable Cox analysis of the 2025-2026 season, age (adjusted hazard ratio, aHR = 1.04 [1.01;1.09]; P = .015), Clinical Frailty Scale (aHR = 1.59 [1.28;1.98]; P < .001), and sequential organ failure assessment score (aHR = 1.15 [1.05;1.26]; P = .003) were associated with an increased risk of death. In the 2024-2025/2025-2026 seasons or 2025-2026 season alone, influenza subtype was not associated with a significant risk of day-28 mortality. Phylogenetic analyses from our ICU cohort together with 600 contextual sequences from community-acquired influenza cases collected during the period showed no clustering according to severity.
Conclusions: There was no evidence of an increased risk of death among critically ill people with influenza during the 2025-2026 season, despite the emergence of influenza A(H3N2) subclade K.
Trial registration: NCT05162508.
Keywords: A(H1N1)pdm09; A(H3N2); acute respiratory failure; influenza; intensive care unit.
. 2026 Nov 11:ciag648.
doi: 10.1093/cid/ciag648. Online ahead of print.
People With Influenza Requiring ICU Admission During the 2025-2026 Season, Marked by the Emergence of Influenza A(H3N2) Subclade K: A French Prospective Nationwide Cohort Study
Nicolas de Prost 1 2 3 , Pierre Bay 1 2 3 , Marie Le Goff 1 2 3 , Sébastien Préau 4 5 , Aurélie Guigon 6 , François M Beloncle 7 , Caroline Lefeuvre 8 , Anaïs Dartevel 9 , Sylvie Larrat 10 , Rémi Coudroy 11 12 , Luc Deroche 13 14 , Cédric Darreau 15 , Jean Thomin 16 , Cécile Aubron 17 , Adissa Tran 18 , Fabrice Uhel 19 20 , Quentin Le Hingrat 21 , Fabienne Tamion 22 , Alice Moisan 23 , Antoine Guillon 24 , Lynda Handala 25 , Bertrand Souweine 26 , Cecile Henquell 27 , Kada Klouche 28 29 , Edouard Tuaillon 30 31 , Charles Damoisel 32 , Anne-Marie Roque-Afonso 33 , Elyanne Gault 34 , Pierre Cappy 3 35 , Alexandre Soulier 3 35 , Jean-Michel Pawlotsky 3 35 , Frédéric Lemoine 36 37 , Marie-Anne Rameix-Welti 38 39 , Etienne Audureau 40 41 , Slim Fourati 3 35 ; SEVARVIR investigators
Collaborators, Affiliations Expand
- PMID: 43012657
- DOI: 10.1093/cid/ciag648
Abstract
Background: Intense influenza activity has been reported alongside the emergence of influenza A(H3N2) subclade K. While epidemiological studies have reported heterogeneous findings regarding public health impact, data remain lacking on its impact on clinical phenotype of people requiring intensive care unit (ICU) admission.
Methods: Prospective, multicenter, observational SEVARVIR cohort study including people admitted in 42 French ICUs with laboratory-confirmed influenza infection during the 2024-2025 and 2025-2026 seasons. Primary end point was day-28 mortality.
Results: Seven hundred twenty-six people were admitted for influenza in 2024-2025 (n = 360) and 2025-2026 (n = 366). In 2025-2026, influenza subtype was available for 265 people; 49% (n = 129) had A(H1N1)pdm09 and 51% (n = 136) had A(H3N2) subtype infection. Among the 40 people with A(H3N2) infection for whom whole-genome sequencing was available, 33 (82.5%) belonged to subclade K. In multivariable Cox analysis of the 2025-2026 season, age (adjusted hazard ratio, aHR = 1.04 [1.01;1.09]; P = .015), Clinical Frailty Scale (aHR = 1.59 [1.28;1.98]; P < .001), and sequential organ failure assessment score (aHR = 1.15 [1.05;1.26]; P = .003) were associated with an increased risk of death. In the 2024-2025/2025-2026 seasons or 2025-2026 season alone, influenza subtype was not associated with a significant risk of day-28 mortality. Phylogenetic analyses from our ICU cohort together with 600 contextual sequences from community-acquired influenza cases collected during the period showed no clustering according to severity.
Conclusions: There was no evidence of an increased risk of death among critically ill people with influenza during the 2025-2026 season, despite the emergence of influenza A(H3N2) subclade K.
Trial registration: NCT05162508.
Keywords: A(H1N1)pdm09; A(H3N2); acute respiratory failure; influenza; intensive care unit.