In early January 2020, Sean Whelan, PhD, the new head of molecular microbiology, met with Michael S. Diamond, MD, PhD, the Herbert S. Gasser Professor of Medicine. The two virologists, both active in the world of emerging infectious diseases, discussed reports of a mysterious new coronavirus that had sickened a few dozen people in the central Chinese city of Wuhan, and considered whether it was significant enough to study. No deaths had been reported. Over the coming months, the new coronavirus would spread around the world, infecting tens of millions of people, killing more than 2 million and transforming the day-to-day lives of just about everyone. At the School of Medicine, scientists and physicians would launch themselves into the frantic worldwide effort to end the pandemic.