Why Adenovirus COVID Vaccines Caused Blood Clots (And What It Means) Adenovirus vaccine blood clots were caused by a rare misdirected immune response called vaccine-induced immune thrombotic thrombocytopenia, or VITT. New research in the New England Journal of Medicine shows that in people with specific immunoglobulin light-chain gene variants, IGLV3-21*02 or *03, antibodies first raised against an adenoviral core protein, pVII, can acquire a somatic mutation that shifts binding to the human protein PF4, activating platelets and triggering clots.

Curious why some adenovirus COVID vaccines led to rare clots? It traces to a misdirected immune response (VITT). See what scientists found—and what it could mean for future shots. What questions do you have? #adenovirus #COVID19 #PF4Antibodies #vaccines #VITT