Acquired thrombotic thrombocytopenic purpura: A rare disease associated with BNT162b2 vaccine.

A disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) activity should be evaluated in patients with history of aTTP before and after any vaccination, especially the SARS-CoV-2 vaccination, and immunosuppression treatment should be considered before vaccination in cases of low ADAMTS13 activity. Patients should be closely monitored after the vaccine for clinical situation and laboratory data. Post vaccination thrombocytopenia assessment should include immune thrombocytopenic purpura, vaccine-induced immune thrombotic thrombocytopenia and acquired thrombotic thrombocytopenic purpura.