{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,7]],"date-time":"2026-03-07T06:35:37Z","timestamp":1772865337456,"version":"3.50.1"},"reference-count":8,"publisher":"Oxford University Press (OUP)","issue":"5","license":[{"start":{"date-parts":[[2025,8,21]],"date-time":"2025-08-21T00:00:00Z","timestamp":1755734400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100021515","name":"Sanofi","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100021515","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Danish Cardiovascular Academy"},{"DOI":"10.13039\/501100009708","name":"Novo Nordisk Foundation","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100009708","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100007405","name":"Danish Heart Foundation","doi-asserted-by":"publisher","award":["NNF20SA0067242"],"award-info":[{"award-number":["NNF20SA0067242"]}],"id":[{"id":"10.13039\/100007405","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2025,8,29]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:sec>\n                  <jats:title>Aims<\/jats:title>\n                  <jats:p>Atrial fibrillation (AF) may be associated with adverse influenza-related outcomes. We assessed the relative vaccine effectiveness (rVE) of high-dose (HD-IIV) vs. standard-dose (SD-IIV) inactivated influenza vaccination against cardiovascular and all-cause hospitalizations and all-cause mortality according to history of AF.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Methods and results<\/jats:title>\n                  <jats:p>This was a prespecified analysis of DANFLU-1, a pragmatic, open-label, feasibility trial randomizing adults aged 65-79 years 1:1 to HD-IIV or SD-IIV during the 2021-2022 influenza season in Denmark. Baseline and endpoint data were obtained from the nationwide administrative health registries. Prespecified endpoints included cardiovascular hospitalizations and all-cause mortality occurring 14 days after vaccination until 31 May 2022. Among 12 477 randomized participants, 878 (7.0%) had AF at baseline. Participants with AF were older (73.0 \u00b1 3.8 vs. 71.7 \u00b1 3.9 years, P &amp;lt; 0.001), more likely to be male (70.7% vs. 51.5%, P &amp;lt; 0.001) and have concomitant comorbidities. The incidence rate of hospitalization for AF was 75.5 vs. 5.1 per 1000 person-years for individuals with vs. without AF (P &amp;lt; 0.001). HD-IIV vs. SD-IIV was associated with a lower all-cause mortality rate irrespective of AF status (AF: 9 events, rVE 54.1%, 95% CI \u2212114.7 to 92.6% vs. no AF: 53 events, rVE 48.3%, 95% CI 6.3-72.5%, pinteraction = 0.87). HD-IIV was not associated with a lower incidence of AF hospitalization regardless of AF status (overall rVE: 29.7%, 95% CI \u221213.9 to 57.1, pinteraction = 0.51).<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Conclusion<\/jats:title>\n                  <jats:p>Although DANFLU-1 was not powered for clinical endpoints, HD-IIV vs. SD-IIV was associated with lower all-cause mortality irrespective of AF status. HD-IIV compared with SD-IIV was not associated with a significantly lower incidence of AF hospitalizations regardless of AF status.<\/jats:p>\n               <\/jats:sec>","DOI":"10.1093\/ehjopen\/oeaf102","type":"journal-article","created":{"date-parts":[[2025,8,21]],"date-time":"2025-08-21T16:43:21Z","timestamp":1755794601000},"source":"Crossref","is-referenced-by-count":1,"title":["Relative vaccine effectiveness of high-dose vs. standard-dose influenza vaccine against clinical outcomes according to history of atrial fibrillation: a pre-specified analysis of the DANFLU-1 randomized trial"],"prefix":"10.1093","volume":"5","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2879-8862","authenticated-orcid":false,"given":"Caroline","family":"Espersen","sequence":"first","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital\u2014Herlev and Gentofte , Copenhagen, Gentofte Hospitalsvej 8, 2900 Hellerup ,","place":["Denmark"]},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen , Gentofte Hospitalsvej 8, 2900 Hellerup ,","place":["Denmark"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6959-3236","authenticated-orcid":false,"given":"Niklas Dyrby","family":"Johansen","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital\u2014Herlev and Gentofte , Copenhagen, Gentofte Hospitalsvej 8, 2900 Hellerup ,","place":["Denmark"]},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen , Gentofte Hospitalsvej 8, 2900 Hellerup ,","place":["Denmark"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7566-0519","authenticated-orcid":false,"given":"Daniel","family":"Modin","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital\u2014Herlev and Gentofte , Copenhagen, Gentofte Hospitalsvej 8, 2900 Hellerup ,","place":["Denmark"]},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen , Gentofte Hospitalsvej 8, 2900 Hellerup ,","place":["Denmark"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0391-5981","authenticated-orcid":false,"given":"Kira Hyldek\u00e6r","family":"Janstrup","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital\u2014Herlev and Gentofte , Copenhagen, Gentofte Hospitalsvej 8, 2900 Hellerup ,","place":["Denmark"]},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen , Gentofte Hospitalsvej 8, 2900 Hellerup ,","place":["Denmark"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Matthew M","family":"Loiacono","sequence":"additional","affiliation":[{"name":"Sanofi Vaccines, Medical Evidence Generation, Sanofi, 100 Morris St, Morristown , NJ 07960 ,","place":["USA"]},{"name":"Department of Epidemiology, University of Delaware, 100 Discovery Blvd, Newark, DE 19713 ,","place":["USA"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rebecca C","family":"Harris","sequence":"additional","affiliation":[{"name":"Sanofi Vaccines , Medical Evidence Generation, 38 Beach Road , 189767","place":["Singapore"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4209-2778","authenticated-orcid":false,"given":"Tor","family":"Biering-S\u00f8rensen","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital\u2014Herlev and Gentofte , Copenhagen, Gentofte Hospitalsvej 8, 2900 Hellerup ,","place":["Denmark"]},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen , Gentofte Hospitalsvej 8, 2900 Hellerup ,","place":["Denmark"]},{"name":"Department of Cardiology, Copenhagen University Hospital\u2014Rigshospitalet , Blegdamsvej 9, 2100 Copenhagen 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cohort study","volume":"8","author":"Kao","year":"2017","journal-title":"Oncotarget"},{"key":"2025090802114662100_oeaf102-B4","doi-asserted-by":"crossref","first-page":"368","DOI":"10.1016\/j.cardfail.2008.11.009","article-title":"Decreased immune responses to influenza vaccination in patients with heart failure","volume":"15","author":"Vardeny","year":"2009","journal-title":"J Card Fail"},{"key":"2025090802114662100_oeaf102-B5","doi-asserted-by":"crossref","first-page":"635","DOI":"10.1056\/NEJMoa1315727","article-title":"Efficacy of high-dose versus standard-dose influenza vaccine in older adults","volume":"371","author":"DiazGranados","year":"2014","journal-title":"N Engl J Med"},{"key":"2025090802114662100_oeaf102-B6","doi-asserted-by":"crossref","first-page":"101330","DOI":"10.1016\/j.jacadv.2024.101330","article-title":"Prevalence, management, and comorbidities of adults with atrial fibrillation in the United States, 2019 to 2023","volume":"3","author":"Oltman","year":"2024","journal-title":"JACC Adv"},{"key":"2025090802114662100_oeaf102-B7","doi-asserted-by":"crossref","first-page":"EVIDoa2200206","DOI":"10.1056\/EVIDoa2200206","article-title":"A pragmatic randomized feasibility trial of influenza vaccines","volume":"2","author":"Johansen","year":"2023","journal-title":"NEJM Evid"},{"key":"2025090802114662100_oeaf102-B8","doi-asserted-by":"crossref","first-page":"100786","DOI":"10.1016\/j.lanepe.2023.100786","article-title":"Atrial fibrillation: epidemiology, screening and digital health","volume":"37","author":"Linz","year":"2024","journal-title":"Lancet Reg Health Eur"}],"container-title":["European Heart Journal 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