Vaccine-induced Immune Thrombotic Thrombocytopenia: Frequently Asked Questions
(Version 1.1; last updated April 16, 2021)
Input from: James Bussell, 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; Ingrid Pabinger, MD
On April 13, the U.S. Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention suggested pausing administration of the AD26.COV2.S Johnson & Johnson (JJ) vaccine to allow investigation of several cases of a severe clotting and thrombocytopenia syndrome being termed “vaccine-induced immune thrombotic thrombocytopenia (VITT)” occurring post-vaccination. This announcement comes on the heels of the initial reports of VITT in individuals receiving the CHaDOx1 nCov-19 AstraZeneca (AZ) vaccine outside the United States. Clinical and laboratory characteristics of VITT have recently been reported.1,2,3 The incidence of this constellation of findings appears extremely low following either vaccine, with causality not established.(read more)
