The purpose of this study is to see if a vaccine that is being developed to prevent people from getting sick with COVID-19 is safe and effective and also to see how well it is tolerated. Participants will receive a shot of either the vaccine or a placebo twice: once on Day 1 and a booster shot on Day 29. Participants will have blood drawn several times for the next 24 months to assess your immune system's (how your body fights off the virus) response. Participation will last about 24 months. Participants will receive payment in return for their time and effort.
INVESTED is a multi-site trial comparing high-dose (60 μg per vaccine viral strain) trivalent influenza vaccine to standard-dose (15 μg per viral strain) quadrivalent influenza vaccination for up to three influenza seasons in high-risk cardiovascular disease patients with a history of myocardial infarction in the previous 12 months OR history of heart failure hospitalization in the previous 24 months. Subjects will be randomly assigned to receive either the high-dose or standard-dose vaccine.