AstraZeneca vaccine’s side effects. Why Covishield takers shouldn’t worry

Since the British-Swedish pharmaceutical giant AstraZeneca’s admission that its COVID-19 vaccine can cause a rare side effect of blood clotting has come to light, concerns have arisen about its safety among those who took the jab in India. The vaccine was marketed as Covishield in the South Asian country and was manufactured by the Pune-based Serum Institute of India (SII).

This comes as AstraZeneca reportedly accepted in a court in the United Kingdom that its COVID-19 vaccine, developed by Oxford University, could cause Thrombosis with  Thrombocytopenia Syndrome (TTS) in “very rare cases”.

What is TTS? Should those who took the Covishield vaccine worry? Let’s take a closer look.

What is TTS?

Thrombosis with Thrombocytopenia Syndrome is a rare condition that leads to blood clotting and low platelet count.

“TTS is a very rare condition resulting from an abnormal immune response. Although it has several causes, it has also been linked with adenovirus vector vaccines,” Dr Rajeev Jayadevan, co-chairman of the Indian Medical Association’s National Covid-19 Task Force, told the news agency IANS.

The symptoms of TTS include consistent headaches, blurred vision, shortness of breath, pain in the chest, leg swelling, or persistent abdominal pain.

Also known as vaccine-induced prothrombotic immune thrombocytopenia (VIPIT) or vaccine-induced immune thrombotic thrombocytopenia (VITT), the rare condition was reported in some people who got adenoviral vector COVID-19 vaccines such as AstraZeneca’s Vaxzevria (sold as Covishield in India) and the Johnson & Johnson’s Janssen shots.

The case against AstraZeneca

According to the British newspaper The Daily Telegraph, AstraZeneca has confessed for the first time that its COVID-19 vaccine may cause TTS.

The pharmaceutical giant is facing 51 litigations in the UK High Court. The victims and grieving relatives are seeking 100 million pounds in damages, alleging that the COVID-19 vaccine caused severe harm and deaths, according to reports.

While AstraZeneca is contesting the claims, it has “accepted, in a legal document submitted to the High Court in February that its Covid vaccine ‘can, in very rare cases, cause TTS’”, The Daily Telegraph reported.

Releasing a statement on Tuesday (30 April), AstraZeneca said, “Our sympathy goes out to anyone who has lost loved ones or reported health problems. Patient safety is our highest priority, and regulatory authorities have clear and stringent standards to ensure the safe use of all medicines, including vaccines”.

Should people worry?

No, there is no need to panic.

Doctors say the benefits of the COVID-19 vaccine are far greater than its rare side effects. Moreover, it was already known that AstraZeneca’s jab could cause TTS.

A senior health ministry official told Indian Express, “TTS is a very rare side effect, rarer still in Indians and South Asians as compared to Europeans. But there is enough evidence to show that vaccination saved lives — the benefits outweighed the risks.”

According to the World Health Organisation (WHO), the vaccine is “safe and effective for all individuals aged 18 and above”, and TTS was a “rare adverse event”.

The first cases were reported in Europe within months of the launch of immunisation drives, with some countries even stopping the use of AstraZeneca’s vaccine for a while, noted Indian Express.

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 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, as per the Indian Express report.

In India, 175 crore shots of Covishield were administered. At least 36 cases of TTS and 18 deaths from the condition were confirmed in 2021 – the year India launched the COVID-19 vaccination drive – by the government panel on Adverse Events Following Immunisation (AEFI), the newspaper report mentioned.

It must be noted that the adverse effects of the vaccine would have occurred within days or weeks of taking the jab, experts say.

“The adverse effects related to vaccine usually occur within a few weeks (1-6 weeks) after the administration. Hence, people in India who took the vaccine two years ago need not worry,” Dr Sudhir Kumar, a neurologist at Apollo Hospital, Hyderabad, told India Today.

Notably, the product information that came with Covishield warned about TTS, while adding that the “majority of the events occurred within the first 21 days following vaccination and some events had a fatal outcome”.

Dr Jayadevan, who is quoted earlier in the story, said that clotting was an issue when the first vaccine dose was administered and in the month after vaccination. “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 said, as per The Hindu.

After the reports about AstraZeneca’s admission surfaced, Delhi health minister Saurabh Bharadwaj asked the Centre to “urgently address” the issue. “The Central government should urgently address the alleged side-effects of the vaccine because millions of people in India have been vaccinated with Covishield,” he said to PTI on Tuesday.

Social media users in India also expressed concerns about the vaccine.

Speaking to Indian Express, Dr Anurag Agarwal, Dean of Biosciences and Health Research at the Trivedi School of Biosciences of Ashoka University, called people’s reaction “surprising”. “The rare side effect was well documented and scientifically accepted even when the vaccination drives were going on. The benefit of vaccination at the height of the pandemic outweighed the risk.”

Moreover, doctors say those who received the vaccine are less likely to die from COVID-19. “People who are vaccinated have an overall lower risk of death from COVID as well as complications such as post-COVID heart attacks and strokes afterward”, Dr Jayadevan told IANS.

With inputs from agencies