Funding Support and Author Disclosures In this collaboration between the Center for Translational Cardiology and Pragmatic Randomized Trials at the Department of Cardiology, Copenhagen University Hospital–Herlev and Gentofte, University of Copenhagen, Denmark, and the private vaccination provider Danske Lægers Vaccinations Service/European LifeCare Group (ELCG), Center for Translational Cardiology and Pragmatic Randomized Trials acts as trial sponsor and the central trial coordination site and is responsible for the overall study design, conduct, registry-based recruitment and data collection, and safety monitoring. DAN-RSV is funded by Pfizer Inc who participated in the study design and protocol and statistical analysis plan development, but had no responsibilities in trial conduct, data collection, or data analysis. All Pfizer authors are employees of the company and may own Pfizer stock. Dr Skaarup was financed by a research grant from the Danish Cardiovascular Academy, which is funded by the Novo Nordisk Foundation and the Danish Heart Foundation (NNF20SA0067242); has served on advisory boards for Sanofi; and has received travel support from AstraZeneca. Dr Claggett has received consulting fees from Amgen, Cardurion, Corvia, Myokardia, and Novartis. Dr Larsen has received speaker fees and served on advisory boards for GlaxoSmithKline, Moderna, Merck Sharp & Dohme, Pfizer, Takeda, and Valneva. Dr Køber has received speaker fees from Novo Nordisk, Novartis, AstraZeneca, Boehringer Ingelheim, and Bayer. Dr Solomon has received research grants from Actelion, Alnylam, Amgen, AstraZeneca, Bellerophon, Bayer, Bristol Myers Squibb, Celladon, Cytokinetics, Eidos, Gilead, GlaxoSmithKline, Ionis, Lilly, Mesoblast, MyoKardia, National Institutes of Health/National Heart, Lung, and Blood Institute, Neurotronik, Novartis, Novo Nordisk, Respicardia, Sanofi, Theracos, and US2.AI; and has consulted for Abbott, Action, Akros, Alnylam, Amgen, Arena, AstraZeneca, Bayer, Boehringer Ingelheim, Bristol Myers Squibb, Cardior, Cardurion, Corvia, Cytokinetics, Daiichi Sankyo, GlaxoSmithKline, Lilly, Merck, Myokardia, Novartis, Roche, Theracos, Quantum Genomics, Cardurion, Janssen, Cardiac Dimensions, Tenaya, Sanofi, Dinaqor, Tremeau, CellProThera, Moderna, American Regent, Sarepta, Lexicon, Anacardio, Akros, and Puretech Health. Dr Mebazaa has received research contracts from 4TEEN4, Roche, Sphingotec, Abbott Diagnostics, and Windtree; has received consultation fees from Roche, Corteria, Adrenomed, Fire, and Johnson & Johnson; has received honorarium for lecture from Merck, Novartis, Roche, and Bayer; is co-inventor of a patent on combined therapies to treat dyspnea, owned by S-Form Pharma; and is a member of the Committee of trials for Secret-HF, sponsored by the French Government, for S-Form Pharma, for 4TEEN4, Echosens and Implicity. Dr Biering-Sørensen has received research grants from Bayer, Novartis, Pfizer, Sanofi Pasteur, GlaxoSmithKline, Novo Nordisk, AstraZeneca, Boston Scientific, and GE Healthcare; has received consulting fees from Novo Nordisk, IQVIA, Parexel, Amgen, CSL Seqirus, GlaxoSmithKline, and Sanofi Pasteur; and has received lecture fees from AstraZeneca, Bayer, Novartis, Sanofi Pasteur, GE Healthcare, and GlaxoSmithKline. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.