Abstract
The COVID-19 pandemic created an urgent need to develop preventive vaccines to blunt the impact of the greatest global health crisis in a century. Two vaccines, both employing mRNA technology, were developed from bench to bedside in under one year - a milestone considered nearly impossible. This paper examines the evolving safety profile of mRNA-1273, from development under Operation Warp Speed through Emergency Use Authorization, and subsequent deployment at nearly unprecedented scale. Vaccine safety was characterized during clinical development and refined through well-established safety monitoring systems (e.g. Vaccine Adverse Event Reporting System [VAERS]), as well as newly introduced systems such as V-Safe. Key safety findings, such as myocarditis, are reviewed as well as safety findings in special populations. The complementary contributions of public, private, and academic sectors highlight how collaboration and rigorous monitoring supported timely and comprehensive safety assessment of a new vaccine in the extraordinary setting of a global pandemic.