Bourguignon A, Arnold DM, Warkentin TE, et al. - Per recommendations, high-dose intravenous immune globulin (IVIG) plus anticoagulation is required for the treatment of vaccine-induced immune thrombotic thrombocytopenia (VITT), a rare side effect of adenoviral vector vaccines against coronavirus disease 2019 (Covid-19). Researchers aimed at reporting the response to IVIG therapy in three of the first patients experiencing VITT after the receipt of the ChAdOx1 nCoV-19 vaccine in Canada. The patients were aged between 63 and 72 years; one of them was female. In two of the patients, limb-artery thrombosis was observed at presentation and the third patient presented with cerebral venous and arterial thrombosis. In response to heparin and platelet factor 4 (PF4), serum-induced platelet activation appeared at variable patterns, indicating the heterogeneity of the manifestations of VITT in serum. All three patients showed reduction in antibody-induced platelet activation in serum after the initiation of IVIG.