VWF and COVID-19: Examples for indirect mechanisms of platelet activation during SARS-CoV-2 infection include specific immunoglobulins found in sera of COVID-19 patients that induce procoagulant platelets via FcγRIIa signaling (11, 12), endothelial dysfunction with increased expression of von Willebrand factor (vWF) (56, 57) and stimulation of platelets by proinflammatory markers during the cytokine storm complicating severe cases of COVID-19 (58, 59).