Study reveals cause of deadly blood clots in some COVID-19 vaccine patients

Editor's Note

A new study looked at the causes behind how some patients developed deadly blood clots following the administration of certain COVID-19 vaccines. The findings were published in the journal Blood on October 26. 

Previous studies had shown that patients with Vaccine-Induced Immune Thrombocytopenia and Thrombosis (VITT) produce antibodies that stick to a protein called Platelet factor 4 (PF4), creating a cluster of molecules called an immune complex. This complex led to clotting, but the precise mechanism was not known. For this study, researchers took blood taken from healthy donors, as well as serum and plasma from patients with VITT, and discovered how PF4 triggered the production of the small cells known to cause clotting.

The researchers say that the findings will allow them to develop new drugs to inhibit this mechanism and prevent deadly clotting. In addition to guiding future vaccine programs, the findings may help researchers identify ways to prevent clotting seen in other diseases.