Thrombus formation in iTTP is related to a severe deficiency of the specific von Willebrand-factor-cleaving protease ADAMTS13 due to ADAMTS13 autoantibodies.<h4>Methods</h4>We present a case of iTTP following exposure to the mRNA-based COVID-19 vaccine BNT162b2 (Comirnaty<sup>®</sup>, Pfizer-BioNTech). This evidence concerns the gene ADAMTS13 and COVID-19.