However, the anti–SARS-CoV-2 adenovirus-vectored vaccines, initially the ChAdOx1-S vaccine (Vaxzevria, AstraZeneca) and later the Janssen Ad26.COV2.S vaccine (Johnson & Johnson) have been linked to the development of a severe, life-threatening thromboembolic complication with thrombocytopenia—a condition termed vaccine-induced immune thrombotic thrombocytopenia (VITT) because of the formation of antibodies against platelet factor 4 (PF4) that activates platelets via the Fcγ receptors [[1], [2], [3]]. Here, PF4 is linked to Thrombocytopenia.