AstraZeneca vaccine linked to another rare disorder, finds study

Over a week after AstraZeneca announced a global withdrawal of its coronavirus vaccine due to a slowdown in sales and the availability of alternative vaccines, new research has linked the vaccine to a rare disorder.

Researchers have found that the AstraZeneca vaccine, known as Covishield in India, is associated with a rare blood clotting disorder called Vaccine-Induced Immune Thrombocytopenia and Thrombosis (VITT).

What is the rare disease

Scientists from Flinders University, Australia, published their findings in the New England Journal of Medicine, revealing that VITT emerged in 2021 during the Covid-19 pandemic, particularly following the use of the Oxford-AstraZeneca vaccine, which employs adenovirus vectors.

The disorder is caused by a harmful blood autoantibody targeting a protein called platelet factor 4 (PF4). Further research in 2023 identified a similar, sometimes fatal disorder linked to natural adenovirus infections, such as the common cold, involving the same PF4 antibody.

Autoantibodies are antibodies produced by the immune system that mistakenly target and attack the body’s own tissues, leading to autoimmune diseases. In VITT, patients often develop blood clots in unusual locations like the brain or abdomen and exhibit high levels of a substance called D-dimer in their blood.

Also Read: Parents consider lawsuit against Serum Institute of India after daughter’s death following Covishield dose

A genetic risk factor

Dr Jing Jing Wang and Professor Tom Gordon from Flinders University had previously identified a genetic risk factor related to the PF4 antibody in 2022. Their recent collaboration with international researchers discovered that PF4 antibodies in both vaccine-related VITT and natural adenovirus infections share identical molecular signatures.

The study, using a novel method developed at Flinders University, indicates that a common factor in viruses and vaccines triggers these harmful antibodies. The mechanisms of antibody production in these disorders are nearly identical and share similar genetic risk factors.

Professor Gordon emphasized that these findings have significant clinical implications. The insights gained from VITT can apply to rare blood clotting cases after natural adenovirus infections and can aid in improving vaccine safety.

Also Read: AstraZeneca pulls out Covishield vaccine from across the globe amid controversy

Symptoms of the rare blood clot disease

According to the American Society of Hematology, Vaccine-Induced Immune Thrombotic Thrombocytopenia (VITT) occurs within 4 to 42 days of receiving the Covid vaccine.

Therefore, if you are outside this window, there is no need for concern. Symptoms of VITT include severe headache, visual changes, abdominal pain, nausea and vomiting, back pain, shortness of breath, leg pain or swelling, and easy bruising or bleeding. If you experience any of these symptoms after vaccination, seek medical attention promptly.

Court admission by AstraZeneca

Recently, AstraZeneca made a significant admission in court documents, acknowledging for the first time that its Covid-19 vaccine can cause rare side effects, including Thrombosis with Thrombocytopenia Syndrome (TTS), which is characterized by blood clots and low blood platelet counts.

In India and other low- and middle-income countries, the Covid-19 vaccine developed by AstraZeneca in collaboration with the University of Oxford was manufactured and distributed under the brand name “Covishield” by the Serum Institute of India (SII).

This arrangement was made possible through a licensing agreement between SII, the University of Oxford, and AstraZeneca, enabling the production and distribution of the vaccine to a broader population, particularly in countries where access to vaccines and healthcare resources may be limited.