Covishield Facts: What Is TTS? Can Indians Develop This Condition Due To AstraZeneca Vaccine?

AstraZeneca has admitted that its Covid vaccine can in rare cases cause a blood clotting condition, TTS. India has widely administered Covishield. Do Indians need to worry? Here is what experts say.

Covishield side-effects: Covishield Fact Check: Experts have said there is no need to panic.

Source : Canva (modified)

Covishield Facts: Pharmaceutical giant AstraZeneca has in a legal submission in the United Kingdom admitted that its Covid-19 vaccine can in "very rare cases" cause a side-effect identified as thrombosis with thrombocytopenia syndrome (TTS), which may lead to blood clotting and low platelet count. In its document submitted to the High Court in London, the UK-headquartered British-Swedish multinational company said the causal link between the vaccine and the specific condition is unknown, according to reports in the UK media.

The admission by AstraZeneca has caused panic across the world, including in India where 1.75 billion (175 crore) doses of the Covid vaccine’s Indian version, Covishield, have been administered. In India, Covishield is manufactured by the Serum Institute of India in Pune.

Ever since the publication of the news, several social media users have been posting messages claiming that Indians are at risk of TTS now. They are blaming the Indian government for allowing Covishield in the country. 

So, what is the truth? 

Let’s first know what is ‘thrombosis with thrombocytopenia syndrome’, or TTS, and how serious the health condition is.

What Is TTS? How Serious Is The Condition And What Are The Symptoms?

TTS is seen as a serious health condition that causes blood clots (thrombosis) and low platelet count (thrombocytopenia) in the body. “The condition is linked to adenovirus vector vaccines launched during Covid-19,” Dr Saumya Saluja writes for The Healthy Indian Project, a fact-checking website that debunks health-related misinformation.

According to Dr Saluja, the symptoms of TTS range from chest pain, shortness of breath, swelling in the legs, stomach ache, and severe and continuous headaches. Affected persons may also suffer from easy bruising.

Lawyers representing the petitioners who challenged the British-Swedish pharma firm in the UK court noted in their submission that the consequences of TTS were potentially life-threatening as they included strokes, heart attacks, brain damage, pulmonary embolism, and amputation, the UK media reports said. 

AstraZeneca-Covishield Link 

AstraZeneca developed its Covid vaccine in collaboration with Oxford University. In Europe, the vaccine is known as Vaxzevria. The same vaccine is available in India under the brand name Covishield and is manufactured by the Pune-based Serum Institute. Both vaccines are said to be identical in their formulation.

The World Health Organization (WHO) has described the AZ vaccine as “safe and effective for all individuals aged 18 and above”.

Categorised under adenovirus vector vaccine, it has been reported, that the AstraZeneca vaccine — both Vaxzevria and Covishield — showed 60-80% protection against Covid infection two weeks after the second dosage during the clinical trials. 

What Does The AstraZeneca Legal Submission Say?

“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 Guardian reported, quoting the legal document submitted in the London court.

AstraZeneca UK Ltd was taken to court by a group of 51 claimants, who have sought damages under Section 2 of the UK’s Consumer Protection Act 1987 to compensate for the loss sustained as a result of the vaccine. According to the report, lawyers argued that the claimants and their loved ones suffered TTS after receiving the AZ vaccine. Of the 51 claimants, 12 are fighting the case on behalf of a loved one who died.

“All of those within the group have death certificates or medical evidence confirming that the vaccine caused the deaths and injuries suffered,” Sarah Moore, partner at Leigh Day, the law firm representing the claimants, was quoted as saying.

In a statement, AstraZeneca has 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.” 

It added: “From the body of evidence in clinical trials and real-world data, the AstraZeneca-Oxford vaccine has continuously been shown to have an acceptable safety profile and regulators around the world consistently state that the benefits of vaccination outweigh the risks of extremely rare potential side effects.” 

Can Covishield-Vaccinated Indians Develop TTS?

While the admission by AstraZeneca through a legal submission that its COVID-19 vaccine can cause TTS is a recent development, the pharma multinational, as well as the Serum Institute in India, have for long listed the condition among its side effects.   

In its statement, AstraZeneca pointed out that product information about the vaccine was updated in April 2021, with the UK regulator’s approval, to add “the possibility that the AstraZeneca-Oxford vaccine is capable, in very rare cases, of being a trigger for” TTS.

The WHO had also certified the vaccine as “safe and effective”, acknowledging that the adverse effect was “very rare”. “A very rare adverse event called Thrombosis with Thrombocytopenia Syndrome (TTS), involving unusual and severe blood clotting events associated with low platelet counts, has been reported after vaccination with this vaccine. In countries with ongoing SARS-CoV-2 transmission, the benefit of vaccination in protecting against COVID-19 far outweighs the risks.”

On its website, SII says most of the Covishield side-effects occur 6-8 hours after the shot has been administered and “resolve within 2 to 3 days”. It also says side-effects are “uncommon by Day 5 to 7 after vaccination, indicating that these effects are self-limiting and of short duration”. According to SII, “adverse reactions are relatively less after the second dose as compared to the first dose”.

The FAQ section related to the Covishield vaccine lists the side effects divided into 5 categories — ‘very common’, ‘common’, ‘uncommon’, ‘not known’, and ‘rarest’.  

“Major blood clotting (venous and/or arterial thrombosis) in combination with low platelet count (thrombocytopenia) have been observed very rarely (with a frequency less than 1 in 100,000 vaccinated individuals),” reads the ‘rarest’ description.

While chills, fever, headache, nausea, joint pain or muscle ache are listed as “very common” side effects, that could affect “more than 1 in 10 people”, the ‘common’ reactions include “swelling or redness where the injection is given, fever, being sick (vomiting) or diarrhoea, pain in legs or arms, flu-like symptoms, such as high-temperature sore throat, runny nose, cough and chills”.

Sleepiness or feeling dizzy, stomach pain, enlarged lymph nodes, excessive sweating, itchy skin, rash or hives are listed as “uncommon” side effects that “may affect up to 1 in 100 people”. 

“The fact that the side effects from the AstraZeneca vaccine have been acknowledged in a court in the U.K. has been used by those with other agendas and misrepresented as something that AstraZeneca were hiding and forced to admit. This fits into the narrative that people were forced to take a vaccine that harms them, which is completely untrue (sic),” Prof. Hassan Vally, associate professor in epidemiology at Deakin University, tells Logically Facts, another fact-checking organisation. 

So, is the Covishield-vaccinated Indian population at risk of acquiring TTS?

“A little. But there is still no reason to panic,” Dr Saumya Saluja writes in the The Healthy Indian Project (THIP) report. THIP is a member of the WHO’s Vaccine Safety Net (VSN) that seeks to provide accurate information about vaccines. 

Covishield is the most widely administered Indian vaccine, and there had been “a limited number of TTS so far reported across the country in the last few years”, Dr Saluja writes, adding that had TTS resulting from vaccination caused large-scale deaths it would have been noticed and widely reported.

“It also needs to be understood that Thrombosis with thrombocytopenia syndrome (TTS), including vaccine-induced immune thrombotic thrombocytopenia (VITT), is an extremely rare side-effect mostly seen post-initial vaccination. Earlier research has also shown that other vaccine-induced complications like CVST have not yet been documented in India despite the widespread use of Covishield,” she adds.

Dr Saluja says vaccinations have proved to be highly effective and safe in halting the COVID-19 pandemic, but there is a remote chance of rare adverse effects such as TTS and VITT. “Early diagnosis and prompt intervention are key for patient management. It should be emphasized that the safety profiles of the vaccines are meticulously monitored by the regulatory authorities.”

With social media posts creating a panic situation, Dr Saluja says it would be “misleading” and an “exaggeration” to say that all Indians are at risk of dying due to TTS and that it has been a government failure.

Commenting on the rarity of the side effects, Vally tells LF: “It has been known and acknowledged widely that the AstraZeneca vaccine can, on very rare occasions, cause TTS. This has never been in contention since it was identified when the vaccine was rolled out globally. The issue is that the benefits of the vaccine far outweigh the likelihood of side effects.”

Dr Jayadevan, co-chairman of the National Indian Medical Association (IMA) Covid Task Force in Kerala, has also said there is no reason to panic as of now.

“It’s a rare occurrence following specific types of vaccines and other causes,” ANI quotes him as saying. Also, it has been documented that when TTS is reported in rare cases, it is mostly within a few weeks of the vaccination. Hence, the medical advice for those taking the vaccine now is to stay vigilant and consult a doctor in case they face any of the TTS symptoms.

“The risk of TTS has shown to be the highest in the first few weeks after getting the vaccine,” he adds.

Virologist Dr Jacob John, too, says that the risk is short-lived. “COVID pathology can be long-term, but vaccine adverse effects are mostly short-term. The offending substance is given once, and its concentration steadily declines with time. Viruses multiply over time. Vaccine ingredients dissipate with time.” 

AstraZeneca Not The Only Vaccine Linked To TTS

In 2023, WHO noted that TTS is an adverse effect on adenovirus vector-based vaccines.

Janssen, the Covid vaccine from Johnson & Johnson, has also been linked to TTS. “Those clots typically occur in individuals who are bedridden, hospitalized, or have other medical issues related to inflammation, infection, or cancer,” Yale Medicine haematologist Robert Bona, MD, was quoted as saying in a 2023 report.

With inputs from The Health India Project and Logically Facts part of the Shakti Collective.