Clinical Features of Vaccine-Induced Immune Thrombocytopenia and Thrombosis

This prospective cohort study described 220 patients in the United Kingdom diagnosed with vaccine-induced immune thrombocytopenia and thrombosis (VITT) following ChAdOx1 nCoV-19 vaccination. Most patients were younger than 60 years, with no predominant sex or comorbid risk factor. Common presentations included cerebral venous sinus thrombosis, deep-vein thrombosis, and pulmonary embolism. Laboratory features showed thrombocytopenia, markedly elevated D-dimer, and reduced fibrinogen. Anti–PF4 antibodies were found in 90%. Mortality was 22%, highest among those with platelet counts <30,000/mm³ and intracranial hemorrhage. Prognostic markers were identified, including platelet count and hemorrhage, guiding treatment choices such as IVIG, plasma exchange, and non-heparin anticoagulation.

This prospective cohort study described 220 patients in the United Kingdom diagnosed with vaccine-induced immune thrombocytopenia and thrombosis (VITT) following ChAdOx1 nCoV-19 vaccination. Most patients were younger than 60 years, with no predominant sex or comorbid risk factor. Common presentations included cerebral venous sinus thrombosis, deep-vein thrombosis, and pulmonary embolism. Laboratory features showed thrombocytopenia, markedly elevated D-dimer, and reduced fibrinogen. Anti–PF4 antibodies were found in 90%. Mortality was 22%, highest among those with platelet counts <30,000/mm³ and intracranial hemorrhage. Prognostic markers were identified, including platelet count and hemorrhage, guiding treatment choices such as IVIG, plasma exchange, and non-heparin anticoagulation.