Abstract
BACKGROUND: Since administration of COVID-19 vaccines, there has been growing evidence of thrombotic and thrombocytopenic events following vaccination. However, there remains limited data on long-term management of these adverse hematologic events. KEY CLINICAL QUESTION: We report on 9 patients presenting with thrombocytopenia following COVID-19 vaccination, with 4 subsequently diagnosed with vaccine-induced thrombocytopenia and thrombosis (VITT) and 5 with immune thrombocytopenia. CLINICAL APPROACH: A retrospective chart review was completed for adults >18 years of age presenting to a tertiary care center with new-onset thrombocytopenia occurring 4 to 42 days following COVID-19 vaccination. Presenting symptoms, laboratory investigations, and response to treatment are described. CONCLUSION: Two of 4 patients with VITT developed refractory thrombocytopenia successfully treated with intravenous immunoglobulin, corticosteroids, and plasma exchange therapy. Patients with VITT remained on anticoagulation for at least 9 months due to persistently positive diagnostic tests. Four of 5 patients with immune thrombocytopenia received intravenous immunoglobulin and corticosteroids with good recovery. Patients who received a subsequent COVID-19 mRNA vaccine had no adverse hematologic effects.