One in 35

Myocardial Injury after COVID-19 mRNA-1273 Booster Vaccination Department of Cardiology and Cardiovascular Research Institute Basel (ESC Heart Failure, open-access journal of the Heart Failure Association of the European Society of Cardiology) Prospective active surveillance study (Not a retrospective passive surveillance study) Industry independent, instigated by the investigators Aims Incidence and potential mechanisms of oligosymptomatic myocardial injury, following COVID-19 mRNA booster vaccination. Safety net for those already boosted, screening and prevention of complications Methods and Results December 2021 to February 2022 Hospital employees scheduled to undergo mRNA-1273 booster vaccination, assessed for mRNA-1273 vaccination-associated myocardial injury, defined as acute dynamic increase in high-sensitivity cardiac troponin T (