What is VITT, the other blood clotting condition linked to AstraZeneca’s COVID-19 vaccine? – Firstpost

AstraZeneca's COVID-19 vaccine has been linked to Vaccine-induced Immune Thrombotic Thrombocytopenia, a rare but potentially fatal condition. Reuters File Photo

British-Swedish pharma giant AstraZeneca has remained in the headlines after reports surfaced that it admitted its COVID-19 vaccine can cause a rare side effect of blood clotting. Now, Australian researchers have found a link between vaccine-induced immune thrombocytopenia and thrombosis (VITT), a rare complication associated with AstraZenecas COVID-19 jabs, and an uncommon but potentially fatal blood disease contracted by some who had a cold.

According to Adelaides Flinders University, the antibodies from VITT and an adenovirus VITT-like disorder share nearly identical molecular signatures or fingerprints.

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These findings, using a completely new approach for targeting blood antibodies developed at Flinders University, indicate a common triggering factor on virus and vaccine structures that initiates the pathological PF4 antibodies, the universitys Professor Tom Gordon was quoted as saying by 9news.com.au.

Researchers said these findings will have implications for vaccine development and safety.

What is VITT? Is it different from TTS? How is it linked to AstraZeneca s COVID-19 vaccine? Lets take a closer look.

What is VITT?

VITT is a rare condition found in some people who got adenoviral vector COVID-19 vaccines such as AstraZenecas Vaxzevria and the Johnson & Johnsons Janssen shots.

The adverse effect led to blood clots and low platelet count in healthy young adults.

VITT is marked by venous or arterial thrombosis, particularly at unusual sites including cerebral sinus venous thrombosis (CSVT)/splanchnic thrombosis; mild to severe thrombocytopenia (low platelet count); and positive PF4-heparin ELISA (HIT ELISA), according to American Society of Hematology.

HIT stands for Heparin-induced thrombocytopenia which is an immune complication that can occur in patients exposed to heparin products.

Thrombosis refers to a blood clot within blood vessels that restricts the flow of the red-hued body fluid.

The symptoms of VITT include persistent headaches, shortness of breath, abdominal pain, easy bruising or bleeding, nausea and vomiting.

People who have VITT, their immune response gets compromised and they make antibodies that can stick to one of the bodys own proteins called platelet factor 4 (PF4), as per The Conversation.

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TTS and VITT

AstraZeneca has accepted in court documents in the United Kingdom that its COVID-19 vaccine, in rare cases, can cause Thrombosis with Thrombocytopenia Syndrome (TTS).

TTS is a broader category that can be triggered by vaccine or it can be non-immune mediated. As per ScienceDirect, VITT can be considered as one of several entities that fall under the umbrella of immune-mediated TTS.

A 2022 study in Lancet Global Health revealed that AstraZeneca had reported rates of 8.1 TTS cases per million who got the first dose of its COVID-19 vaccine and 2.3 cases per million after people got the second jab. The highest number of these cases were found in Nordic countries 17.6 per million doses and the lowest in Asian nations 0.2 per million doses.

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In India, at least one young woman is believed to have died from VITT after taking Covishield .

Rithaika Sri Omtri, 18, got the first dose of Covishield in May 2021 in Hyderabad. As per a Scroll report, within five days of being vaccinated, she experienced a prickling sensation in her fingers and, later, a high fever.

As her fever did not subside for a few days, a doctor suggested her a blood test which revealed her platelets had dropped to a dangerous low of 40,000 per cubic millimetre, compared to a normal range between 1.5 lakh and 4 lakh.

Over 10 days later, Rithaika started vomiting and could not walk. An MRI scan of her brain showed that she had multiple blood clots and a haemorrhage in the right frontal region, Scroll reported.

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Despite efforts to save her, she was declared brain dead, two weeks after her vaccination.

Rithaika had suffered a vaccine-induced (immune) thrombotic thrombocytopenia, Scroll reported.

AstraZeneca under scanner

The pharma giant has been under scrutiny since its admission came to light. People who took its COVID-19 vaccine started questioning its safety. However, experts said the side effects appeared within the first few weeks of taking the vaccine and there was no need to worry now.

Recently, AstraZeneca said its COVID-19 vaccine, which was manufactured by the Serum Institute of India (SII) and sold as Covishield in India, has been removed from the markets for commercial reasons.

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With inputs from agencies

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What is VITT, the other blood clotting condition linked to AstraZeneca's COVID-19 vaccine? - Firstpost