PF4 and COVID-19: To investigate the impact of COVID-19 vaccines on inflammation and platelets, we analyzed markers of inflammation, vascular endothelial activation, platelet activation and aggregation, whole blood coagulation, thrombin generation and PF4 antibodies pre- and post-vaccination in a cohort of individuals without VITT receiving either AZ or mRNA [Pfizer/BioNTech BNT162b2 and Moderna mRNA-1273] vaccines.