New Delhi: The ongoing controversy over a possible link between COVID-19 vaccines and a risk of heart attacks has further escalated with a war of words between Karnataka Chief Minister Siddaramaiah and Biocon founder Kiran Mazumdar-Shaw. Charges have flown thick and fast over whether Indian regulators cut corners in fast-tracking vaccine approvals.
In response to a post on ‘X’ by Mazumdar-Shaw, Siddaramaiah stressed in his post on the microblogging site Thursday evening that “scientific caution is not anti-science” and while COVID-19 vaccines may have saved many lives, globally, multiple studies and even admissions by manufacturers acknowledged rare but serious adverse events, including cardiac-related issues among those administered the jab.
Shaw later in a statement on X said she agreed with the chief minister that asking questions and seeking answers is integral to science.
“However, my comments related to whether Covid vaccines were approved in haste n my response was that due process was followed as prescribed by WHO for safety n efficacy for EUA. Losing lives in a sudden manner is always tragic n I am glad an investigation is being conducted in Hassan District,” she added.
I agree with Hon CM @siddaramaiah re asking questions n seeking answers in science. However, my comments related to whether Covid vaccines were approved in haste n my response was that due process was followed as prescribed by WHO for safety n efficacy for EUA. Losing lives in a… https://t.co/SPYhZRYAjM
— Kiran Mazumdar-Shaw (@kiranshaw) July 4, 2025
Siddaramaiah on 1 July suggested a link between COVID-19 vaccines and several cardiac-related deaths reported in Karnataka’s Hassan district over the last month. Later he also announced that an expert committee headed by a senior cardiologist has been tasked with bringing out a report on the cause of the deaths.
On Thursday, Shaw wrote that COVID-19 vaccines developed in India were approved under the Emergency Use Authorisation framework, following rigorous protocols aligned with global standards for safety and efficacy.
To suggest that these vaccines were ‘hastily’ approved is factually incorrect and contributes to public misinformation, she wrote, adding that these vaccines have saved millions of lives and, like all vaccines, may cause side effects in a very small number of individuals. “It is important to acknowledge the science and data-driven processes behind their development, rather than engage in retrospective blame.”
In response, Siddaramaiah retorted that as a chief minister, he had a duty to respond to genuine concerns of people who have lost loved ones unexpectedly. “When parents lose their young children or families lose breadwinners without warning, seeking clarity is not misinformation; it is an act of governance rooted in empathy,” he wrote on ‘X’.
Many peer-reviewed studies published in journals including Nature, Circulation, Journal of the American College of Cardiology have discussed myocarditis and cardiac arrest risk, particularly among young adults post-vaccination, he said, while also citing a news report carrying a response from AstraZeneca whose Covishield, manufactured by Pune-based Serum Institute of India (SII), was widely used in India.
Publicly funded stakeholders must acknowledge both the benefits and the potential risks without fear or favour, Siddaramaiah stressed. He went on to clarify that when he earlier suggested a likely association between COVID-19 vaccines and instances of cardiac-related deaths, it reflected the unprecedented speed of emergency rollouts globally without complete long-term data, acknowledged even by the World Health Organisation (WHO) and global regulatory agencies, which termed it a ‘calculated risk’ during a pandemic.
“Haste is not a sin when saving lives, but acknowledging potential unintended consequences is wisdom,” he wrote. Seeking answers is not retrospective blame, the CM further wrote, insisting that it is the duty of a government that values every life.
“The governments and other responsible stakeholders should find the truth, act on it, and protect our people with transparency and care,” Siddaramaiah wrote.
Seeking to refute allegations made by the Karnataka chief minister, the Ministry of Health and Family Welfare had issued a detailed statement highlighting that extensive studies by the Indian Council of Medical Research (ICMR) and AIIMS, New Delhi, on sudden deaths among adults post pandemic have conclusively established that there is no link between COVID-19 vaccines and sudden deaths. Instead, lifestyle and pre-existing conditions in those affected were identified as key factors, the government stressed.
Also Read: BJP calls Siddaramaiah ‘anti-science’ for linking cardiac-related deaths in Hassan to COVID vaccines
Evidence so far
The Union government has insisted that ICMR and National Centre for Disease Control (NCDC) under the health ministry have been working together to understand the causes behind sudden unexplained deaths, especially in young adults between the ages of 18 and 45. To explore this, two complementary studies were undertaken using different research approaches—one based on past data and another involving real-time investigation.
The first study, conducted by ICMR’s National Institute of Epidemiology (NIE), was titled “Factors associated with unexplained sudden deaths among adults aged 18-45 years in India–A multicentric matched case–control study”.
This study was carried out from May to August 2023 across 47 tertiary care hospitals in 19 states and Union Territories. It looked at individuals who appeared to be healthy but died suddenly between October 2021 and March 2023. “The findings have conclusively shown that COVID-19 vaccination does not increase the risk of unexplained sudden death in young adults,” Dr Manoj Murhekar, director ICMR-NIE, told ThePrint.
Instead, history of hospitalisation with COVID-19, binge drinking, recreational use of drugs, family history of heart attacks and rigorous physical activities including exercise up to 48 hours before the death were identified as major risk factors behind these deaths, he said.
The senior epidemiologist also said findings from the committee, formed by Karnataka government, will shed more light on this. “Let’s see what this committee finds,” he said.
The second study, titled “Establishing the cause in sudden unexplained deaths in young,” is currently being conducted by AIIMS with funding and in collaboration with ICMR. This is a prospective study aimed at determining the common causes of sudden death in young adults.
Early analysis of data from the study indicates that heart attacks, or myocardial infarction (MI), continue to be the leading cause of sudden death in this age group, AIIMS doctors said in a press interaction Thursday. Importantly, no major changes in the pattern of causes have been observed when compared to previous years. In the majority of the unexplained deaths, genetic mutations have been identified as a possible cause, doctors said, adding that final results will be shared once the study is complete.
Dr Mohit Gupta, a senior cardiologist with G.B. Pant Hospital in New Delhi, who had also examined risk factors for heart attacks in over 1,500 people who had died at the centre and compared them with a control group, also maintained that vaccines, in fact, were found to be protective and brought down mortality in people.
“The fact that severe COVID-19 has a thrombosis effect (cause of sudden blood clots in arteries which can lead to heart attacks) at least for several months following infection is now well established world over,” Gupta told ThePrint.
However, said the interventional cardiologist, in absence of evidence to suggest that COVID-19 vaccines could be causing heart attacks in healthy individuals, such suggestions look guided by “emotion rather than science”.
According to Dr N.K. Arora, who heads the National Technical Advisory Group on Immunisation (NTAGI), India, had rolled out COVID-19 vaccines after gathering adequate evidence to ensure that these were safe. NTAGI is the top advisory body that guides the government policy in vaccination. In addition, the country, Arora said, had put in place robust district level Adverse Event Following Immunisation (AEFI) committees to catch all statistics on side effects related to Covid 19 vaccines.
“If COVID-19 vaccines would have been causing heart attacks in healthy individuals it would be a massive concern for the country but all the statistics collected through nationwide AEFI data and ICMR studies has ruled it out,” Arora told ThePrint.
The Indian Pharmaceutical Alliance and Indian Vaccine Manufacturers Association, a network of top Indian drugmakers and vaccine makers too came out in support of the COVID-19 vaccines Thursday saying that the allegations made by Karnataka CM were not backed by scientific evidence.
Disclosure: Kiran Mazumdar-Shaw is among the distinguished founder-investors of ThePrint. Please click here for details on investors.
(Edited by Viny Mishra)
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