{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,4]],"date-time":"2026-11-04T21:34:23Z","timestamp":1793828063626,"version":"4.6.1"},"reference-count":34,"publisher":"American Medical Association (AMA)","issue":"11","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JAMA Cardiol"],"published-print":{"date-parts":[[2025,11,1]]},"abstract":"\n Importance<\/jats:title>\n The high-dose inactivated influenza vaccine (HD-IIV) has demonstrated superior protection against laboratory-confirmed influenza infection vs standard-dose IIV (SD-IIV); however, data regarding its effectiveness against cardiovascular (CV) outcomes are mainly from observational studies or specific high-risk groups.<\/jats:p>\n <\/jats:sec>\n \n Objective<\/jats:title>\n To investigate the relative vaccine effectiveness (rVE) of HD-IIV vs SD-IIV against CV outcomes in the general older adult population in Denmark.<\/jats:p>\n <\/jats:sec>\n \n Design, Setting, and Participants<\/jats:title>\n This was a prespecified secondary analysis of DANFLU-2, a pragmatic, open-label, individually randomized clinical trial (RCT) using nationwide administrative health registries in Denmark during the 2022\/2023 to 2024\/2025 influenza seasons. Older adults (age \u226565 years) were eligible for inclusion regardless of comorbidity. The trial design specified that if the primary end point was neutral, no hypothesis testing would be performed for secondary or exploratory end points. Data were analyzed from June 29 to August 12, 2025.<\/jats:p>\n <\/jats:sec>\n \n Interventions<\/jats:title>\n Individual-level 1:1 randomization to HD-IIV or SD-IIV. Participants re-enrolling in additional seasons were rerandomized.<\/jats:p>\n <\/jats:sec>\n \n Main Outcomes and Measures<\/jats:title>\n Severe CV outcomes were prespecified secondary and exploratory end points in the trial, occurring from 14 days after vaccination through May 31 the following year.<\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n A total of 332\u202f438 participants (170\u202f900 [51.4%] male; mean [SD] age, 73.7 [5.8] years) were randomized (166\u202f218 to HD-IIV and 166\u202f220 to SD-IIV), of whom 91\u202f026 (27.4%) had a history of CV disease. HD-IIV did not significantly reduce the trial\u2019s primary end point of hospitalization for influenza or pneumonia. The incidence of hospitalization for any cardiorespiratory disease was lower in the HD-IIV group than the SD-IIV group (rVE, 5.7% [95% CI, 1.4% to 9.9%]; absolute difference, \u22120.13 [95% CI, \u22120.24 to \u22120.03] percentage points), and rVE did not differ by history of CV disease compared with no CV disease at baseline. Hospitalization for any CV disease occurred in fewer participants in the HD-IIV group than the SD-IIV group (rVE, 7.5% [95% CI, 1.5% to 12.5%]; absolute difference, \u22120.10 [95% CI, \u22120.18 to \u22120.02] percentage points) as did hospitalization for heart failure (rVE, 19.5% [95% CI, 3.3% to 33.1%]; absolute difference, \u22120.03 [95% CI, \u22120.06 to \u22120.01] percentage points).<\/jats:p>\n <\/jats:sec>\n \n Conclusions and Relevance<\/jats:title>\n This study found reduced incidence of cardiorespiratory hospitalization among those who received HD-IIV vs SD-IIV, driven by a lower incidence of CV hospitalizations, and particularly heart failure hospitalizations. These differences should be interpreted as exploratory findings in the setting of a large RCT with a neutral primary outcome.<\/jats:p>\n <\/jats:sec>\n \n Trial Registration<\/jats:title>\n \n ClinicalTrials.gov Identifier:\n NCT05517174<\/jats:ext-link>\n <\/jats:p>\n <\/jats:sec>","DOI":"10.1001\/jamacardio.2025.3460","type":"journal-article","created":{"date-parts":[[2025,8,30]],"date-time":"2025-08-30T12:30:20Z","timestamp":1756557020000},"page":"1186","source":"Crossref","is-referenced-by-count":22,"title":["High-Dose vs Standard-Dose Influenza Vaccine and Cardiovascular Outcomes in Older Adults"],"prefix":"10.1001","volume":"10","author":[{"given":"Niklas Dyrby","family":"Johansen","sequence":"first","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Daniel","family":"Modin","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matthew M.","family":"Loiacono","sequence":"additional","affiliation":[{"name":"Sanofi, Morristown, New Jersey"},{"name":"Department of Epidemiology, University of Delaware, Newark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rebecca C.","family":"Harris","sequence":"additional","affiliation":[{"name":"Sanofi, Singapore, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marine","family":"Dufournet","sequence":"additional","affiliation":[{"name":"Sanofi, Lyon, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Carsten Schade","family":"Larsen","sequence":"additional","affiliation":[{"name":"Department of Clinical Medicine \u2013 Department of Infectious Diseases, Aarhus University Hospital, Aarhus, Denmark"},{"name":"Danske L\u00e6gers Vaccinations Service\/European LifeCare Group, S\u00f8borg, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lykke","family":"Larsen","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases, Odense University Hospital, Odense, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lothar","family":"Wiese","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases, Zealand University Hospital, Roskilde, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michael","family":"Dalager-Pedersen","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases, Aalborg University Hospital, Aalborg, Denmark"},{"name":"Department of Clinical Medicine, Aalborg University Hospital, Aalborg, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Brian L.","family":"Claggett","sequence":"additional","affiliation":[{"name":"Cardiovascular Division, Brigham and Women\u2019s Hospital, Harvard Medical School, Boston, Massachusetts"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kira Hyldek\u00e6r","family":"Janstrup","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Katja Vu","family":"Bartholdy","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Katrine Feldballe","family":"Bernholm","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Julie Inge-Marie Helene","family":"Borchsenius","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Filip Soeskov","family":"Davidovski","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lise Witten","family":"Davodian","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maria","family":"Dons","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lisa Steen","family":"Duus","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Caroline","family":"Espersen","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Frederik Holme","family":"Fussing","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anne Marie Reimer","family":"Jensen","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nino Emanuel","family":"Landler","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Adam Cadovius Femerling","family":"Langhoff","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mats Christian H\u00f8jbjerg","family":"Lassen","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anne Bjerg","family":"Nielsen","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Camilla Ikast","family":"Ottosen","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Morten","family":"Sengel\u00f8v","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kristoffer Grundtvig","family":"Skaarup","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Manan","family":"Pareek","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Scott D.","family":"Solomon","sequence":"additional","affiliation":[{"name":"Cardiovascular Division, Brigham and Women\u2019s Hospital, Harvard Medical School, Boston, Massachusetts"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Martin J.","family":"Landray","sequence":"additional","affiliation":[{"name":"Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gunnar H.","family":"Gislason","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"},{"name":"The Danish Heart Foundation, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lars","family":"K\u00f8ber","sequence":"additional","affiliation":[{"name":"Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"},{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Rigshospitalet, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pradeesh","family":"Sivapalan","sequence":"additional","affiliation":[{"name":"Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"},{"name":"Respiratory Medicine Section, Department of Medicine, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cyril Jean-Marie","family":"Martel","sequence":"additional","affiliation":[{"name":"Statens Serum Institut, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jens Ulrik St\u00e6hr","family":"Jensen","sequence":"additional","affiliation":[{"name":"Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"},{"name":"Respiratory Medicine Section, Department of Medicine, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tor","family":"Biering-S\u00f8rensen","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Herlev and Gentofte, Copenhagen, Denmark"},{"name":"Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"},{"name":"Department of Cardiology, Copenhagen University Hospital \u2013 Rigshospitalet, Copenhagen, Denmark"},{"name":"Steno Diabetes Center Copenhagen, Herlev, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"10","reference":[{"issue":"4","key":"hoi250055r1","doi-asserted-by":"publisher","first-page":"345","DOI":"10.1056\/NEJMoa1702090","article-title":"Acute myocardial infarction after laboratory-confirmed influenza infection.","volume":"378","author":"Kwong","year":"2018","journal-title":"N Engl J Med"},{"issue":"4","key":"hoi250055r2","doi-asserted-by":"publisher","first-page":"363","DOI":"10.1001\/jamacardio.2019.0549","article-title":"Association of influenza-like illness activity with hospitalizations for heart failure: the Atherosclerosis Risk in Communities Study.","volume":"4","author":"Kyt\u00f6maa","year":"2019","journal-title":"JAMA Cardiol"},{"issue":"6","key":"hoi250055r3","doi-asserted-by":"publisher","first-page":"1189","DOI":"10.1016\/j.hrthm.2016.01.026","article-title":"The association between influenza infection, vaccination, and atrial fibrillation: A nationwide case-control study.","volume":"13","author":"Chang","year":"2016","journal-title":"Heart Rhythm"},{"issue":"3","key":"hoi250055r4","doi-asserted-by":"publisher","first-page":"278","DOI":"10.1161\/CIRCULATIONAHA.111.071100","article-title":"Influenza vaccination and major adverse vascular events in high-risk patients.","volume":"126","author":"Johnstone","year":"2012","journal-title":"Circulation"},{"issue":"5","key":"hoi250055r5","doi-asserted-by":"publisher","first-page":"575","DOI":"10.1161\/CIRCULATIONAHA.118.036788","article-title":"Influenza vaccine in heart failure.","volume":"139","author":"Modin","year":"2019","journal-title":"Circulation"},{"issue":"9","key":"hoi250055r6","doi-asserted-by":"publisher","first-page":"2226","DOI":"10.2337\/dc20-0229","article-title":"Influenza vaccination is associated with reduced cardiovascular mortality in adults with diabetes: a nationwide cohort study.","volume":"43","author":"Modin","year":"2020","journal-title":"Diabetes Care"},{"key":"hoi250055r7","doi-asserted-by":"publisher","DOI":"10.1093\/eurheartj\/ehaf384","article-title":"Vaccination as a new form of cardiovascular prevention: a European Society of Cardiology clinical consensus statement: with the contribution of the European Association of Preventive Cardiology (EAPC), the Association for Acute CardioVascular Care (ACVC), and the Heart Failure Association (HFA) of the ESC.","author":"Heidecker","year":"2025","journal-title":"Eur Heart J"},{"issue":"18","key":"hoi250055r8","doi-asserted-by":"publisher","first-page":"1476","DOI":"10.1161\/CIRCULATIONAHA.121.057042","article-title":"Influenza vaccination after myocardial infarction: a randomized, double-blind, placebo-controlled, multicenter trial.","volume":"144","author":"Fr\u00f6bert","year":"2021","journal-title":"Circulation"},{"issue":"38","key":"hoi250055r9","doi-asserted-by":"publisher","first-page":"3720","DOI":"10.1093\/eurheartj\/ehad191","article-title":"2023 ESC Guidelines for the management of acute coronary syndromes.","volume":"44","author":"Byrne","year":"2023","journal-title":"Eur Heart J"},{"issue":"21","key":"hoi250055r10","doi-asserted-by":"publisher","first-page":"1661","DOI":"10.1001\/jama.1994.03520210045030","article-title":"The efficacy of influenza vaccination in elderly individuals: a randomized double-blind placebo-controlled trial.","volume":"272","author":"Govaert","year":"1994","journal-title":"JAMA"},{"issue":"2","key":"hoi250055r11","doi-asserted-by":"publisher","first-page":"172","DOI":"10.1086\/599790","article-title":"Randomized, double-blind controlled phase 3 trial comparing the immunogenicity of high-dose and standard-dose influenza vaccine in adults 65 years of age and older.","volume":"200","author":"Falsey","year":"2009","journal-title":"J Infect Dis"},{"issue":"4","key":"hoi250055r12","doi-asserted-by":"publisher","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"},{"issue":"7","key":"hoi250055r13","doi-asserted-by":"publisher","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"},{"issue":"1","key":"hoi250055r14","doi-asserted-by":"publisher","first-page":"39","DOI":"10.1001\/jama.2020.23649","article-title":"Effect of high-dose trivalent vs standard-dose quadrivalent influenza vaccine on mortality or cardiopulmonary hospitalization in patients with high-risk cardiovascular disease: a randomized clinical trial.","volume":"325","author":"Vardeny","year":"2021","journal-title":"JAMA"},{"key":"hoi250055r15","doi-asserted-by":"publisher","DOI":"10.1016\/j.ahj.2025.07.069","article-title":"A Pragmatic individually randomized trial to evaluate the effectiveness of high-dose vs. standard-dose influenza vaccine in older adults: rationale and design of the DANFLU-2 Trial.","author":"Johansen","year":"2025","journal-title":"Am Heart J"},{"key":"hoi250055r16","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMoa2509907","article-title":"High-dose influenza vaccine effectiveness against hospitalization in older adults.","author":"Johansen","year":"2025","journal-title":"N Engl J Med"},{"issue":"6","key":"hoi250055r18","doi-asserted-by":"publisher","first-page":"397","DOI":"10.1002\/pst.1649","article-title":"Control of type 1 error in a hybrid complete two-period vaccine efficacy trial.","volume":"13","author":"Dunning","year":"2014","journal-title":"Pharm Stat"},{"issue":"39","key":"hoi250055r19","doi-asserted-by":"publisher","first-page":"5825","DOI":"10.1016\/j.vaccine.2019.08.016","article-title":"Safety and immunogenicity of high-dose quadrivalent influenza vaccine in adults =65 years of age: a phase 3 randomized clinical trial.","volume":"37","author":"Chang","year":"2019","journal-title":"Vaccine"},{"issue":"14","key":"hoi250055r20","doi-asserted-by":"publisher","first-page":"1256","DOI":"10.1056\/NEJMp2314801","article-title":"The end of B\/Yamagata influenza transmission\u2014transitioning from quadrivalent vaccines.","volume":"390","author":"Monto","year":"2024","journal-title":"N Engl J Med"},{"key":"hoi250055r21","doi-asserted-by":"publisher","first-page":"449","DOI":"10.2147\/CLEP.S91125","article-title":"The Danish National Patient Registry: a review of content, data quality, and research potential.","volume":"7","author":"Schmidt","year":"2015","journal-title":"Clin Epidemiol"},{"issue":"7","key":"hoi250055r22","doi-asserted-by":"crossref","first-page":"625","DOI":"10.1056\/NEJMoa1105594","article-title":"Stroke and bleeding in atrial fibrillation with chronic kidney disease.","volume":"367","author":"Olesen","year":"2012","journal-title":"N Engl J Med"},{"issue":"2","key":"hoi250055r23","doi-asserted-by":"crossref","DOI":"10.1056\/EVIDoa2200206","article-title":"A Pragmatic randomized feasibility trial of influenza vaccines.","volume":"2","author":"Johansen","year":"2023","journal-title":"NEJM Evid"},{"issue":"10382","key":"hoi250055r24","doi-asserted-by":"crossref","first-page":"1103","DOI":"10.1016\/S0140-6736(23)00349-5","article-title":"Electronic nudges to increase influenza vaccination uptake in Denmark: a nationwide, pragmatic, registry-based, randomised implementation trial.","volume":"401","author":"Johansen","year":"2023","journal-title":"Lancet"},{"issue":"1","key":"hoi250055r25","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1038\/s41541-022-00444-6","article-title":"The feasibility of pragmatic influenza vaccine randomized controlled real-world trials in Denmark and England.","volume":"7","author":"Nealon","year":"2022","journal-title":"NPJ Vaccines"},{"issue":"8","key":"hoi250055r26","doi-asserted-by":"crossref","first-page":"857","DOI":"10.1002\/(SICI)1097-0258(19980430)17:8<857::AID-SIM777>3.0.CO;2-E","article-title":"Two-sided confidence intervals for the single proportion: comparison of seven methods.","volume":"17","author":"Newcombe","year":"1998","journal-title":"Stat Med"},{"key":"hoi250055r28","doi-asserted-by":"crossref","DOI":"10.1016\/j.jvacx.2023.100327","article-title":"High-dose influenza vaccine in older adults by age and seasonal characteristics: systematic review and meta-analysis update.","volume":"14","author":"Lee","year":"2023","journal-title":"Vaccine X"},{"issue":"38","key":"hoi250055r29","doi-asserted-by":"crossref","first-page":"4988","DOI":"10.1016\/j.vaccine.2015.07.006","article-title":"Prevention of serious events in adults 65 years of age or older: a comparison between high-dose and standard-dose inactivated influenza vaccines.","volume":"33","author":"DiazGranados","year":"2015","journal-title":"Vaccine"},{"issue":"47","key":"hoi250055r30","doi-asserted-by":"crossref","first-page":"6700","DOI":"10.1016\/j.vaccine.2022.09.085","article-title":"High-dose influenza vaccines for the prevention of hospitalization due to cardiovascular events in older adults in the nursing home: post-hoc analysis of a cluster-randomized trial.","volume":"40","author":"Saade","year":"2022","journal-title":"Vaccine"},{"issue":"4","key":"hoi250055r31","doi-asserted-by":"crossref","DOI":"10.1001\/jamanetworkopen.2022.8873","article-title":"Association of influenza vaccination with cardiovascular risk: a meta-analysis.","volume":"5","author":"Behrouzi","year":"2022","journal-title":"JAMA Netw Open"},{"issue":"9","key":"hoi250055r32","doi-asserted-by":"crossref","first-page":"1685","DOI":"10.1002\/ejhf.2945","article-title":"Influenza vaccination and cardiovascular events in patients with ischaemic heart disease and heart failure: a meta-analysis.","volume":"25","author":"Modin","year":"2023","journal-title":"Eur J Heart Fail"},{"issue":"12","key":"hoi250055r33","doi-asserted-by":"crossref","first-page":"e1835","DOI":"10.1016\/S2214-109X(22)00432-6","article-title":"Influenza vaccine to reduce adverse vascular events in patients with heart failure: a multinational randomised, double-blind, placebo-controlled trial.","volume":"10","author":"Loeb","year":"2022","journal-title":"Lancet Glob Health"},{"issue":"11","key":"hoi250055r34","doi-asserted-by":"crossref","DOI":"10.1136\/bmjopen-2016-012832","article-title":"Positive predictive value of cardiovascular diagnoses in the Danish National Patient Registry: a validation study.","volume":"6","author":"Sundb\u00f8ll","year":"2016","journal-title":"BMJ Open"},{"key":"hoi250055r17","unstructured":"Agency for Digital Government. Digital Post. Accessed January 18, 2023. https:\/\/en.digst.dk\/systems\/digital-post\/"},{"key":"hoi250055r27","unstructured":"World Health Organization. WHO seasonal influenza vaccine global market study. Updated January 31, 2024. Accessed August 8, 2025. https:\/\/www.who.int\/publications\/m\/item\/who-seasonal-influenza-vaccine-global-market-study-january-2024"}],"container-title":["JAMA Cardiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/jamanetwork.com\/journals\/jamacardiology\/articlepdf\/2838476\/jamacardiology_johansen_2025_oi_250055_1762209204.35134.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,11,12]],"date-time":"2025-11-12T16:01:33Z","timestamp":1762963293000},"score":1,"resource":{"primary":{"URL":"https:\/\/jamanetwork.com\/journals\/jamacardiology\/fullarticle\/2838476"}},"subtitle":["A Prespecified Secondary Analysis of the DANFLU-2 Randomized Clinical Trial"],"short-title":[],"issued":{"date-parts":[[2025,11,1]]},"references-count":34,"journal-issue":{"issue":"11","published-print":{"date-parts":[[2025,11,1]]}},"URL":"https:\/\/doi.org\/10.1001\/jamacardio.2025.3460","relation":{},"ISSN":["2380-6583"],"issn-type":[{"value":"2380-6583","type":"print"}],"subject":[],"published":{"date-parts":[[2025,11,1]]}}}