Vaccine-Induced Immune Thrombotic Thrombocytopenia following BNT162b2 mRNA COVID-19 Booster: A Case Report

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a life-threatening complication caused by platelet activation via platelet factor 4 (PF4) antibodies. We report a healthy 28-year-old man who developed hemoptysis, bilateral leg pain, and headaches three weeks after his third dose of the COVID-19 vaccine with the first BNT162b2 (from Pfizer-BioNTech) injection. He had previously had the first and second doses with ChAdOx1 nCov-19 without any discomfort. Serial investigations demonstrated pulmonary embolisms, cerebral sinus, and deep iliac venous thrombosis. Positive PF4 antibody assay (ELISA) confirmed the diagnosis of VITT. He had a prompt response to intravenous immunoglobulins (IVIGs) at a total dose of 2 g/kg and his symptoms are now in remission with anticoagulant. Although the definite mechanism is unknown, the VITT was most likely triggered by his COVID-19 vaccine. We report this case of VITT following BNT162b2, a mRNA-based vaccine, and suggest that VITT could still happen without the adenoviral vector vaccines.

Automated summary

This is a case report of Vaccine-induced immune thrombotic thrombocytopenia (VITT) following BNT162b2 (Pfizer-BioNTech) vaccine. A healthy 28-year-old man developed hemoptysis, bilateral leg pain, and headaches three weeks after his third dose of the COVID-19 vaccine. Further investigations revealed pulmonary embolisms, cerebral sinus, and deep iliac venous thrombosis. The diagnosis of VITT was confirmed by positive PF4 antibody assay. The patient responded well to intravenous immunoglobulins (IVIGs) and his symptoms are now under control with anticoagulant therapy. This case suggests that VITT can occur with mRNA-based vaccines like BNT162b2, and not just with adenoviral vector vaccines.