Experts explain post-vaccination risks and do the risk-benefit analysis
Global pharmaceutical manufacturer AstraZeneca has admitted that its Covid-19 vaccine, developed by researchers from the Oxford University, can cause a rare side effect of blood clotting and low platelet count after immunisation. In India, the same vaccine, called Covishield and manufactured by the Pune-based Serum Institute, has been administered through 175 crore doses. Understandably, this raises questions as to the safety of the jab all of us took.
The company made this admission of a side effect, Thrombosis with Thrombocytopenia Syndrome (TTS), in court as it faces a lawsuit alleging severe harm and deaths caused by the vaccine, according to The Daily Telegraph. While this may be the company’s first admission in court, TTS has been well-documented and accepted in scientific literature. The first cases came to light within months of the vaccination drives beginning in Europe, with some countries halting the use of the AstraZeneca vaccine for a while.
WHAT DOES THE CASE MEAN FOR COVISHIELD USERS IN INDIA?
The Government committee on Adverse Events Following Immunisation (AEFI), vetted at least 36 cases of TTS and confirmed 18 deaths from it in 2021, the first year of Covid-19 vaccination in the country. However, it is unlikely that affected Indian patients can join the British petition due to legal hurdles such as approvals coming from different regulators and the product being manufactured by an Indian company, which is subject to Indian jurisdiction and laws.
WHY IS THERE NO NEED TO PANIC?
Experts say that TTS was reported early on in the pandemic by European countries but it was very rare in India. A senior health ministry official, who was part of the discussions on the vaccination drive says, “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.”
Besides, the risk is not only rare but is high only in the first few weeks after the first vaccination. Most Indians have already had three shots and it has been a long time since. Says Dr Gagandeep Kang, Director of Global Health at the Bill and Melinda Gates Foundation, who was on the WHO safety advisory committee for COVID-19 vaccines, “It is most important to reassure people that the risk of TTS is shortly after vaccination. We are all long past vaccination now,” she adds.
“It is surprising that people are reacting now. 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,” says Dr Anurag Agarwal, Dean of Biosciences and Health Research at the Trivedi School of Biosciences of Ashoka University.
Besides, the package insert for Covishield always came with a warning about the rare condition. “A very rare and serious (side effect) … has been observed following vaccination with ChAdOx1 nCoV-19 Corona Virus Vaccine (Recombinant) during post-authorisation use… Cases have occurred in patients with a previous history of thrombosis, as well as in patients with autoimmune disorders. The benefits and risks of vaccination should be considered in these patients.”
A 2022 study in Lancet Global Health found that AstraZeneca had reported rates of 8.1 TTS cases per million receiving the first dose and 2.3 TTS cases per million receiving the second dose. The study also showed that there was a geographic variation in the reporting of TTS, with the highest cases coming from Nordic countries (17.6 per million doses) and the lowest from Asian countries (0.2 per million doses).
Besides, the package insert for Covishield always came with a warning about the rare condition. “A very rare and serious (side effect) … has been observed following vaccination with ChAdOx1 nCoV-19 Corona Virus Vaccine (Recombinant) during post-authorisation use… Cases have occurred in patients with a previous history of thrombosis, as well as in patients with autoimmune disorders. The benefits and risks of vaccination should be considered in these patients.”
A 2022 study in Lancet Global Health found that AstraZeneca had reported rates of 8.1 TTS cases per million receiving the first dose and 2.3 TTS cases per million receiving the second dose. The study also showed that there was a geographic variation in the reporting of TTS, with the highest cases coming from Nordic countries (17.6 per million doses) and the lowest from Asian countries (0.2 per million doses).