evidence: While we regularly review and update the information provided here, this FAQ reflects only the best information available at a given point in time. The COVID-19 pandemic is a rapidly evolving global health crisis and new information may have become available since the revision date for each published FAQ. (Version 1.9; last updated May 9, 2022) Input from James B. Bussel, MD; Jean M. Connors, MD; Douglas B. Cines, MD; Cynthia E. Dunbar, MD; Laura C. Michaelis, MD; Lisa Baumann Kreuziger, MD; Agnes Y. Y. Lee, MD, MSc; and Ingrid Pabinger-Fasching, MD.