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

Background: In December 2020 the Israeli Health Ministry began a mass vaccination campaign with the BNT162b2 vaccine. This was an important step in overcoming the severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) pandemic. Autoimmune phenomenon have been described after receiving vaccinations. Patients/Methods: Here we describe a case series of patients who developed acquired Thrombotic Thrombocytopenic Purpura, a rare autoimmune disease, within several days of receiving the BNT162b2 vaccine. Conclusions: 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.