'No link between Covid vaccine and sudden deaths': Serum Institute responds to heart attack death concerns

The Serum Institute of India, manufacturer of Covishield, on Thursday reaffirmed the safety of Covid-19 vaccines amid rising concerns over sudden deaths in Karnataka, citing recent government-backed studies that found no link between vaccination and cardiac fatalities. "The vaccines are safe and scientifically validated," the Covishield maker said, echoing the Indian Health Ministry's findings based on research by ICMR and AIIMS.

Responding to public concern following a series of heart attack deaths in Karnataka's Hassan, the SII issued a statement saying: "Two large-scale studies by ICMR and AIIMS, as cited by the Ministry of Health have found no link between COVID-19 vaccines and sudden deaths. The vaccines are safe and scientifically validated."

The clarification came a day after the Ministry of Health and Family Welfare issued a detailed rebuttal to claims that Covid-19 vaccines might be associated with sudden deaths. "The matter of sudden unexplained deaths has been investigated through several agencies in the country. These studies have conclusively established that there is no direct link between COVID-19 vaccination and the reports of sudden deaths in the country,” the ministry said.

The ministry cited two major investigations. The first, conducted by ICMR’s National Institute of Epidemiology, involved 47 tertiary care hospitals across 19 states and Union Territories. Titled “Factors associated with unexplained sudden deaths among adults aged 18–45 years in India – A multicentric matched case–control study”, it found that Covid vaccination did not increase the risk of sudden death in young adults.

The second study, led by AIIMS Delhi in collaboration with ICMR, is ongoing and focuses on real-time causes of sudden deaths in young individuals. Early findings show that heart attacks—specifically myocardial infarction—remain the primary cause of such deaths, with no new pattern emerging post-vaccination. The report also notes that in many cases, genetic mutations were found to be a likely contributor.

The Health Ministry said both studies “offer a more comprehensive understanding of sudden unexplained deaths in young adults in India” and reiterated that speculative links to vaccines are “false and misleading,” warning that such claims could undermine public trust and fuel vaccine hesitancy.

Biocon founder and Executive Chairperson Kiran Mazumdar-Shaw also issued a public response after Karnataka Chief Minister Siddaramaiah questioned the vaccine approval process. "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,” she said. "To suggest that these vaccines were ‘hastily’ approved is factually incorrect and contributes to public misinformation."

Siddaramaiah had earlier said in a social media post that the "hasty approval and distribution" of Covid vaccines could be a reason for heart attack deaths in Hassan district. The Karnataka health department reported over 20 deaths in the district in the past month. The deceased included four individuals aged 20 or below, one aged 21–29, five between 30–40, seven aged 41–59, and one above 60.

The Centre maintains that the risk of sudden cardiac deaths depends on various factors, including genetics, pre-existing conditions, lifestyle, and post-Covid complications—not vaccination. "Scientific experts have reiterated that statements linking COVID vaccination to sudden deaths are false and misleading, and are not supported by scientific consensus," the Health Ministry said.