Thrombosis with Thrombocytopenia Syndrome after SARS-CoV-2 vaccination

Thrombosis in combination with a low platelet count occurs in rare cases after vaccination with the COVID-19 vaccines from AstraZeneca and Janssen. Most of these patients developed a thrombosis in the head (sinus thrombosis). The disease is called vaccine-induced immune thrombotic thrombocytopenia (VITT). There are many unanswered questions about VITT, including: 1. How common is VITT? 2. What are the clinical manifestations and prognosis of VITT? 3. Has the prognosis improved after the introduction of international treatment guidelines? 4. How common are PF4 antibodies (the suspected cause of VITT) in healthy people who are vaccinated? 5. What role do the clotting and immune systems play in VITT? The purpose of this research is to answer these questions. We provide doctors and policy makers with scientific evidence that can be used to optimize vaccination strategies and the treatment of patients with VITT.