Association between influenza vaccination and severe outcomes in adults aged ≥ 65 years hospitalized with laboratory-confirmed influenza: a retrospective cohort study, I-MOVE hospital network, Europe, 2015/16–2024/25

INTRODUCTION: Older adults face an increased risk of influenza-related intensive care unit (ICU) admission and in-hospital death (IHD). Although vaccination reduces hospitalization, its effect on these outcomes remains uncertain. We estimated the association between influenza vaccination and both outcomes among adults aged ≥65 years hospitalized with laboratory-confirmed influenza. RESEARCH DESIGN AND METHODS: We conducted a retrospective cohort study using European I-MOVE hospital network data (2015/16-2024/25); vaccination was defined as vaccine receipt ≥14 days before symptom onset. We estimated pooled-season adjusted risk ratios (aRR) using Poisson regression adjusting for potential confounders. We calculated relative risk reduction (RRR) as (1-aRR)×100, overall and by age group (65-79, ≥80 years). RESULTS: After exclusions, 4,257 patients (five study sites, six seasons) were included. ICU admission occurred in 3% of vaccinated and 5% of unvaccinated patients; IHD occurred in 5% of both groups. RRR was 11% (95% CI: -21-34) against ICU admission (65-79 years: -4%; ≥80 years: 44%). RRR against IHD was 26% (95% CI: 3-43); 17% and 29% in each respective age group. CONCLUSIONS: Vaccination showed little or no association with ICU admission, but was associated with a one-quarter reduction in IHD among hospitalized older adults, reinforcing its benefits against fatal in-hospital outcomes.

Authors

Institutions

Publication Details

Journal
Expert Review of Vaccines
Published
2026-08-27
DOI
https://doi.org/10.1080/14760584.2026.2722420
Primary Topic
Influenza Virus Research Studies
Type
article
Field-Weighted Citation Impact
0.00

Funders

Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

Association between influenza vaccination and severe outcomes in adults aged ≥ 65 years hospitalized with laboratory-confirmed influenza: a retrospective cohort study, I-MOVE hospital network, Europe, 2015/16–2024/25

Silvia Bino, A. Azevedo, Rianne van Gageldonk-Lafeber, Kristin Tolksdorf et al.
Expert Review of Vaccines
Influenza Virus Research Studies
article

Association between influenza vaccination and severe outcomes in adults aged ≥ 65 years hospitalized with laboratory-confirmed influenza: a retrospective cohort study, I-MOVE hospital network, Europe, 2015/16–2024/25

Silvia Bino, A. Azevedo, Rianne van Gageldonk-Lafeber, Kristin Tolksdorf, Mihaela Lazăr, Lisa Domegan, Diogo FP Marques, Petr Husa, Verónica Gomez, Gergő Túri, Goranka Petrović, Flavia Riccardo, Liêm Binh Luong Nguyen, Susana Monge, Marijke Reynders, Anna Parys, Iwona Paradowska‐Stankiewicz, John Paul Cauchi, Lenka Součková, Antonino Bella, Beatrix Oroszi, Francisco Pozo, Ralf Dürrwald, Monika Kuliešė, Odette Popovici, Sierk Marbus, Ausenda Machado, Angela MC Rose, Vesna Višekruna Vučina, Ligita Jančorienė, Camino Trobajo‐Sanmartín, Iván Martínez‐Baz, Baltazar Nunes, Stephen Abela, Róisín Duffy, Chris Robertson, Odile Launay, Jim McMenamin
article en

Abstract

INTRODUCTION: Older adults face an increased risk of influenza-related intensive care unit (ICU) admission and in-hospital death (IHD). Although vaccination reduces hospitalization, its effect on these outcomes remains uncertain. We estimated the association between influenza vaccination and both outcomes among adults aged ≥65 years hospitalized with laboratory-confirmed influenza. RESEARCH DESIGN AND METHODS: We conducted a retrospective cohort study using European I-MOVE hospital network data (2015/16-2024/25); vaccination was defined as vaccine receipt ≥14 days before symptom onset. We estimated pooled-season adjusted risk ratios (aRR) using Poisson regression adjusting for potential confounders. We calculated relative risk reduction (RRR) as (1-aRR)×100, overall and by age group (65-79, ≥80 years). RESULTS: After exclusions, 4,257 patients (five study sites, six seasons) were included. ICU admission occurred in 3% of vaccinated and 5% of unvaccinated patients; IHD occurred in 5% of both groups. RRR was 11% (95% CI: -21-34) against ICU admission (65-79 years: -4%; ≥80 years: 44%). RRR against IHD was 26% (95% CI: 3-43); 17% and 29% in each respective age group. CONCLUSIONS: Vaccination showed little or no association with ICU admission, but was associated with a one-quarter reduction in IHD among hospitalized older adults, reinforcing its benefits against fatal in-hospital outcomes.

Expert Review of VaccinesVol. 25(1)
Semmelweis University (HU), Lithuanian University of Health Sciences (LT), Inserm (FR), Queen Mary University of London (GB), Vilnius University (LT), University of Strathclyde (GB), Université Paris Cité (FR), Masaryk University (CZ), Robert Koch Institute (DE), Istituto Superiore di Sanità (IT), Instituto de Salud Carlos III (ES), Directorate of Health (IS), Instituto de Salud Pública de Navarra (ES), Hôpital Cochin (FR), Assistance Publique – Hôpitaux de Paris (FR), Hrvatski zavod za javno zdravstvo (HR), University Hospital Brno (CZ), National Institute for Public Health and the Environment (NL), Institutul Cantacuzino (RO), National Influenza Center (MN), Public Health Scotland (GB), National Institute of Public Health (LA), AZ Sint-Jan (BE), Health Protection Surveillance Centre (IE), National Institute of Health Dr. Ricardo Jorge (PT), Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (ES), Vesticon (United States) (US), University of Glasgow (GB), Universidade Nova de Lisboa (PT)
Indian National Science Academy, European Centre for Disease Prevention and Control, University College Dublin, Lunds Universitet, Universitair Ziekenhuis Gent, Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, Lietuvos Sveikatos Mokslų Universitetas, Medicinska Fakulteten, Lunds Universitet, National Research, Development and Innovation Office, Norwegian Institute of Public Health
Good health and well-being
Openalex Percentile: Top 10%
Influenza Virus Research Studies
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.