New Delhi: The Telegraph‘s report that the maker of the AstraZeneca vaccine, which was sold in India as Covishield, has “admitted” to an adverse event called ‘Thrombosis with Thrombocytopenia Syndrome’ or TTS in “very rare cases” has led to deluge of social media posts and a growing sense of paranoia among people.
TTS is a spectrum that involves blot clots along with a low platelet count in the body, which at times can cause serious injury or even death.
While there had been reported cases of deaths and serious adverse effects following the administration of the vaccine, all drug regulators and scientific bodies have categorised them as extremely rare occurrences. All of them have said there are risks, but the benefits of the vaccine, including saving lives, have outweighed the risks.
The Wire breaks down the risk v/s benefits scenario for those who took Covishield in India.
How rare is rare?
One of the keywords that was reported to have been used by AstraZeneca, in terms of adverse events occurring, was ‘rare’ – something that most of the commentary is now missing.
But how rare is it? By looking at the data from the UK and the European Union, the Global Advisory Committee on Vaccine Safety assessed that the risk was low. The committee consists of independent vaccine and other domain experts. It advises the World Health Organisation on vaccine safety.
“[The] data from the UK suggest the risk is approximately 4 cases per million adults who receive the vaccine, while the rate is estimated to be approximately 1 per 100, 000 in the European Union (EU),” it said back in 2021. It was in late 2020 and early 2021 that the Covid-19 vaccination drive picked up globally.
There are several other studies that looked into the rate of TTS caused by the AstraZeneca vaccine. One such study looked at the AstraZeneca Global Safety Database in 2022. They found the rate of this adverse event to be 7.5 per million vaccinated persons, while yet another meta-analysis, which studied two mRNA vaccines and the AstraZeneca vaccine, found the rate of severe adverse reactions with the latter as two per million vaccinated in 2020.
For how long does one run the risk of developing clots?
An Australian assessment says the serious adverse events may develop within four to 42 days of administration of the vaccine. The TTS can develop within a short stretch of duration, and not years after the vaccination. Hence any TTS event, or clotting, can’t occur with Covishield/Astrazeneca vaccine unless one has taken it in the immediate past.
“This time period may also stretch to 3-6 months,” Jacob John, an infectious diseases expert with Christian Medical College (CMC) Vellore, told The Wire.
“The vaccine can’t cause an epigenetic effect. It is not something that it has altered your genes,” he explained, and so can’t lead to the development of clots years down the line.
Is this new information?
Another claim that is doing the rounds is that this is the ‘first time’ we have come to know that TTS could take place in rare instances due to the vaccine. While it may be the first time the information has reached such a wide audience, scientific papers had spoken of the issue back in 2021.
Moreover, the company too had put in the public domain something called a ‘package insert’ while rolling out the vaccine for use. That package insert, shared on the AstraZeneca website, mentions the occurrence of clotting as a rare event.
However, what did not happen was adequate publicising of this information. Neither governments around the world, including India’s, nor the company itself, made meaningful efforts to let the risks be known on a large scale. Therefore, people are now raising questions regarding the transparency of governments and vaccine companies – even if such adverse events were rare.
How does the rare clotting happen?
The British Heart Foundation says the exact pathway is still being studied.
Satyajit Rath, a noted immunologist who has also been associated with Institute of Immunology in India, says it may be due to an inadvertent event. Apart from making the antibodies against the Covid-19 virus, the autoantibodies against a protein found in blood called platelet-4 also got developed in some rare cases, he explained.
“This, in turn, seems to be contributing to triggering a cascade of platelet clumping, and, therefore, the clots,” Rath said.
He added that why it happens in the case of some people – even though rare – and not in others, is yet to be understood clearly.
Heart attack because of Covid-19
There are ample studies, like this long-term research, now, on Long Covid – a spectrum of diseases that many have developed even after patients have recovered from the initial infection. Heart attacks are the most common among them. The British Heart Foundation says the clots were far more common after a Covid-19 infection than after the vaccine.
This large-scale study looked into the records of 10.17 million vaccinated and 10.39 million unvaccinated people in the UK, Spain and Estonia. The researched concluded:
“[The] COVID-19 vaccination reduced the risk of post-COVID-19 cardiac and thromboembolic outcomes. These effects were more pronounced for acute COVID-19 outcomes, consistent with known reductions in disease severity; following breakthrough [or reinfection] versus unvaccinated SARS-CoV-2 [virus causing Covid-19] infection.”
Another study by a group of scientists from Oxford University published in 2021 compared the possibility of thrombocytopenia after Covid-19 infection, and after the administration of the AstraZeneca vaccine.
They concluded that there was an ‘increased’ risk of thrombocytopenia (low platelet count) and venous thromboembolism (clotting in veins) in short time intervals after the administration of the first dose of the vaccine.
But they also wrote that these risks were much higher if one got the Covid-19 disease, as compared to the vaccine.
“Importantly, the risks of these outcomes after vaccination were much lower than those associated with SARS-CoV-2 infection in the same population,” they wrote.
Countries suspended/stopped use of AstraZeneca vaccine for young populations
More than a dozen countries, especially in Europe, suspended the use of the AstraZeneca vaccine for an interim period after reports of clotting surfaced in 2021. However, many of them resumed using it a month or so later.
The governments in the UK and Australia have maintained that younger people, especially those below 50, should not take the AstraZeneca vaccine. They recommended alternative vaccines for this age group; Australia recommended Pfizer’s mRNA vaccine for the younger cohort.
Should India have altered its strategy too? The answer heavily rested on the fact that the Indian government did not allow the import of Pfizer or Moderna vaccines. Therefore, it had limited the options for itself, should a change in strategy have been required.
Moreover, the Indian government had hardly initiated any study, like the other governments, to understand the adverse effects of the vaccine on the younger population after its rollout.
“In order to make a good determination of Covid risk versus vaccine risk to an individual, it would be necessary to have really robust evidence for local transmission situations and clinical risk profiles,” Rath said.
Even though the Astrazeneca vaccine-associated adverse effects were rare, Rath questioned whether India had collected reliable background information as the basis for any potential decision to halt vaccine use in a specific set of the population.
Lack of adverse events monitoring system in India
One of the reasons that a paranoia of sorts has taken over people after the reports of AstraZeneca’s admission is the lack of a proper monitoring mechanism for the side effects of Covid-19 vaccines, or Adverse Effects Following Immunisation (AEFI), in India.
Till date, there is no public platform that the Indian government has built where one can easily look into the data regarding this. As against this, many governments around the world have been transparent.
A case in point is this website of the UK’s drug regulator, Medicines and Healthcare products Regulatory Agency (MHRA).
On this website one can look for the number of adverse reactions caused by each of the three available vaccines in the country – two mRNA vaccines of Pfizer and Moderna, and Novovax. Not only have they put in the public domain how many adverse events occurred, they have also put a summary of how many events were reported and studied to be finally characterised as adverse events.
The US’s Vaccine Adverse Events Reporting System (VAERS) gives anyone the opportunity to download data for the vaccine’s side effects.
The public availability of this information is one point. Another worrisome point in India, as far as Covid-19 vaccines are concerned, is how one should report if an adverse event has occurred.
The Ministry of Health and Family Welfare in India created a toll free number for this. But there were no efforts made to widely circulate that number – definitely much less than the efforts taken to convince people to take vaccines.
There have been reports how registering an AEFI event caused due to Covid-19 vaccination has been an uphill task in India. On the other hand, the MHRA has an easy-to-use ‘yellow card reporting’ website for this.
There have been 180 reported deaths in India following Covid-19 vaccination, but experts don’t rule out some sort of an undercounting here
“Our regulator really needs to learn regarding creating an efficient AEFI reporting system,” CMC’s John said. There have been no post-approval real-life long-term studies in India done by the government to understand how the vaccines performed.
“If such a system [of monitoring] isn’t created, then it is bound to hit the trust of the people in Science. Worse, should an epidemic occur again, how are people going to trust [the vaccines],” John asked.
Other vaccines causing side effects
A panic has now set in among common people. They are questioning why this ‘unsafe vaccine’ was rolled out in India. However, there has been no vaccine against any virus in history which was shown to have 100% safety. Rare side effects have been associated even with those jabs which have been in use for decades now.
“The oral polio vaccine can, in rare instances, lead to vaccine-induced poliomyelitis disease,” Rath explained. He cited another example of the BCG vaccine which, in rare instances, can cause severe inflammation and abscess formation.
It is then not entirely unsurprising – and perhaps not a cause for widespread panic – that the Covid-19 vaccine too can lead to rare adverse events.
