AstraZeneca’s submission in U.K. court nothing new, say doctors over Covishield’s potential to cause blood clots

Any adverse event associated with the vaccine would have occurred within 21 days to a month of the first dose, according to doctors

Updated - May 01, 2024 06:22 am IST

Published - April 30, 2024 09:16 pm IST - NEW DELHI

A health worker inoculates a dose of Covishield vaccine to a woman at a special vaccination drive in a government health centre in Hyderabad. FIle

A health worker inoculates a dose of Covishield vaccine to a woman at a special vaccination drive in a government health centre in Hyderabad. FIle | Photo Credit: The Hindu

Following pharmaceutical company AstraZeneca’s admission in U.K. court documents that its vaccine against COVID-19 has the potential to cause Thrombosis with Thrombocytopenia Syndrome (TTS), a rare side effect associated with blood clotting, doctors in India said this is not new information and that they are “well aware of the warning which has been available in India as an insert with the vaccine since the time it was introduced for general public here”.

They added that any adverse event associated with the vaccine would have occurred within 21 days to a month of the first dose.

A report in British newspaper The Daily Telegraph stated that in a legal document submitted to the High Court in London in February for a group action being brought by 51 claimants, AstraZeneca admitted that the vaccine developed with the University of Oxford to protect against Covid-19 may cause TTS in “very rare cases”.

“It is admitted that the AZ vaccine can, in very rare cases, cause TTS. The causal mechanism is not known. Further, TTS can also occur in the absence of the AZ vaccine (or any vaccine). Causation in any individual case will be a matter for expert evidence,” the newspaper quoted the legal document.

Lawyers acting on behalf of the claimants said that those who received the vaccine suffered TTS — a rare syndrome characterised by the concurrence of thrombosis or blood clotting and thrombocytopenia or insufficiency of platelets.

The consequences of TTS are potentially life-threatening including strokes, brain damage, heart attacks, pulmonary embolism and amputation.

Both the Union Health Ministry and COVID-19 vaccine Covishield’s manufacturer Serum Institute of India on Tuesday issued no statement regarding the development. The Oxford–AstraZeneca Covid‑19 vaccine, is sold under the brand name Covishield in India.

In India, the product information that comes with the vaccine clearly mentions TTS in its special warnings and special precautions for use section while adding that “majority of the events occurred within the first 21 days following vaccination and some events had a fatal outcome”.

‘No secret’

Doctors here said that the court admission now is “no secret” and emphasised that Covid-19 itself is known to increase the danger of clotting, heart attacks and stroke both during and after recovery.

Dr. Rajeev Jayadevan, co-chairman of National Indian Medical Association (IMA) Covid Task Force in Kerala, said: “The court admission is nothing new. In fact, these are well documented facts validated since early 2021 (soon after vaccine rollout). The World Health Organisation (WHO) wrote about it in May 2021 and updated in 2023.”

He added that clotting was an issue for persons who were administered the first dose at the time of vaccination and in the first month afterwards. “Therefore, in 2024, people are not at risk of TTS. Also, heart attacks and strokes we see in practice are not caused by TTS, which is an exceptionally rare immunological reaction that leads to clots in certain locations such as the brain and elsewhere,” he added.

Doctors noted that heart attacks and strokes are commonly caused by lifestyle disease, including smoking, drinking, diabetes, hypertension, high cholesterol, and family history of heart disease and more recently Covid-19 being an additional factor. The more the number of risk factors, the greater the risk. People who have been vaccinated are at lower risk for each one of these events during, and after COVID.

“The clotting side effect of this vaccine is already known and is extremely rare. This is not the first time AstraZeneca admits risk of clotting events (again rarest side effect) associated with Covid,” wrote Dr. Cyriac Abby Philips, hepatologist from Kerala, in a social media post.

According to earlier information released by Serum Institute of India: “A very rare and serious combination of TTS in some cases accompanied by bleeding, has been observed with a frequency less than 1/70,000,000.” The manufacturer had added that as with other vaccines, administration of Covishield should be postponed in individuals suffering from an acute severe febrile illness.

Dr. Akshay Budhraja, senior consultant, Respiratory and Sleep Medicine, Aakash Healthcare, Delhi, said: “The vaccine can potentially cause TTS, a very rare side effect, and the side effects occur within weeks to months, not after years.”

“The vaccine has protected millions of people from contracting severe Covid. After the news [of AstraZeneca’s admission], we are definitely getting a lot of queries through calls and physical visits in OPD, from the individuals who were vaccinated with Covishield and regarding medication to avoid side effects of the vaccine. It has been more than two years of getting vaccinated and it has no long term effects. So, there is nothing to worry at present and no medicine is required,” he said.

(With PTI inputs)

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