Over a week after AstraZeneca announced a global withdrawal of its coronavirus vaccine due to a slowdown in sales and the availability of sufficient market options, new research has linked it to a rare disorder.
Researchers have found that the AstraZeneca vaccine is associated with a rare blood clotting disorder called Vaccine-Induced Immune Thrombocytopenia and Thrombosis (VITT).
Scientists from Flinders University in Australia recently published their study in the New England Journal of Medicine, indicating that VITT emerged in 2021 during the COVID-19 pandemic, particularly after the use of the Oxford-AstraZeneca vaccine, which is based on adenovirus vectors.
They discovered that VITT is triggered by a harmful blood autoantibody that targets a protein called platelet factor 4 (PF4). Separate research in 2023 revealed a similar, occasionally fatal disorder linked to natural adenovirus infections, such as the common cold, involving the same PF4 antibody.
What is Vaccine-induced immune thrombotic thrombocytopenia (VITT)
An autoantibody is an antibody produced by the immune system that mistakenly attacks the body’s own tissues, perceiving them as foreign invaders. This can lead to autoimmune diseases, where the immune system damages healthy cells and tissues. Patients affected by this disorder often develop blood clots in unusual locations, such as the brain or abdomen, and have high levels of a substance called D-dimer in their blood. Researchers from Flinders University, Dr Jing Jing Wang and Professor Tom Gordon, had previously identified a genetic risk factor related to the PF4 antibody in 2022.
Their recent collaboration with international researchers found that PF4 antibodies in both vaccine-related VITT and natural adenovirus infections share identical molecular signatures. This new study, utilizing a novel method developed at Flinders University, demonstrates that a common factor in viruses and vaccines triggers these harmful antibodies. The research suggests that the mechanisms of antibody production in these disorders are almost identical and share similar genetic risk factors.
Professor Gordon explained that these findings have significant clinical implications. The insights gained from VITT can be applied to rare blood clotting cases following natural adenovirus infections and can help improve vaccine safety. According to the American Society of Hematology, vaccine-induced immune thrombotic thrombocytopenia (VITT) occurs within 4 to 42 days of receiving the COVID-19 vaccine. Therefore, there’s no need for undue concern. Symptoms could include severe headache, visual changes, abdominal pain, nausea and vomiting, back pain, shortness of breath, leg pain or swelling, and easy bruising or bleeding.