New Delhi: AstraZeneca has announced a global withdrawal of its vaccine on Thursday. This happened as new research linked it to a rare disorder which slowed down its sales and availability of enough options in the market.
Researchers have found that the AstraZeneca vaccine sold in India under the brand name Covishield is linked to a rare blood clotting disorder known as Vaccine-Induced Immune Thrombocytopenia and Thrombosis (VITT). The scientists from Flinders University, Australia, recently shared their study in the New England Journal of Medicine. During the COVID-19 pandemic in 2021, VITT first appeared, especially following the administration of the adenovirus-based Oxford-AstraZeneca vaccine.
Scientists have found that platelet factor 4 (PF4), a protein, is the target of a blood autoantibody that causes VITT. The same PF4 antibody was implicated in a similar, occasionally fatal illness that was connected to common colds and other natural adenovirus infections in 2020 as per research.
An autoantibody is a type of antibody produced by the immune system which mistakenly targets and attacks the body’s tissues thinking that they are foreign invaders. This can lead to autoimmune diseases where the immune system harms the body’s healthy cells and tissues. Patients affected by it often develop blood clots in unusual places like the brain or the abdomen. They also have high levels of a substance called D-dimer in their blood.
The researchers at Flinder University Dr Jing Jing Wang and Professor Tom Gordon, previously identified a genetic risk factor to the PF4 antibody in 2022. The recent collaboration with international researchers has found that PF4 antibodies in both vaccine-related VITT and natural adenovirus infections share identical molecular signatures.
This new study shows that a common factor in viruses and vaccines generates these damaging antibodies. The technology used in this study is a novel approach created at Flinders University. According to the research, these illnesses have similar genetic risk factors and very identical processes of antibody generation. The lessons learnt from VITT can assist increase vaccination safety and be applied to rare cases of blood clotting following spontaneous viral infections.
As per the American Society of Hematology, vaccine-induced immune thrombotic thrombocytopenia (VITT) occurs within 4 to 42 days of taking the COVID-19 vaccine. 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.
