PTC Web Desk: A major nationwide study has put to rest one of the most persistent health worries of the post-pandemic years — whether Covid-19 vaccines raise the risk of heart attacks in young people. The Indian Council of Medical Research (ICMR) has confirmed that neither Covishield nor Covaxin increases the chances of thrombotic events, including heart attacks, in adults aged 18 to 45.

The research was carried out at 25 tertiary care hospitals across the country and involved collaboration with institutions such as Christian Medical College, Ludhiana, and PGIMER, Chandigarh. The findings, released by the National Institute of Epidemiology (ICMR), are expected to offer much-needed clarity to a public that has remained anxious about cardiovascular risks tied to vaccination.

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Our nationwide, multi-centric study, conducted across 25 tertiary hospitals, found no link between COVID-19 vaccination (Covishield and Covaxin) and an increased risk of thrombotic events, including heart attacks, among young adults (18-45) in India.… pic.twitter.com/BlVLlq0bOP

— ICMR National Institute of Epidemiology (@icmr_nie) July 13, 2026

Why the study was needed

Over the past couple of years, several cases of sudden heart attacks and clotting disorders among seemingly healthy young adults sparked debate about a possible connection to Covid-19 vaccines. With conflicting data emerging from different countries and vaccine types, ICMR researchers set out to specifically examine what was driving these cases within the Indian population.

To get clear answers, scientists ran a case-control study between October 2021 and January 2023. They compared hospitalised patients who had suffered a new clot-related event with matched patients who hadn't, looking closely at medical records and conducting phone interviews to map out each person's health background and lifestyle.

What the numbers show

The scale of the study was substantial. Researchers examined 432 heart attack cases against 1,293 matched controls, and separately studied 767 cases of any type of thrombotic event against 2,144 controls. The results pointed clearly toward familiar risk factors rather than vaccination:

• A past history of a clotting event sharply raised the odds of a future heart attack
• Existing health conditions significantly increased risk
• Smokers faced considerably higher odds compared to non-smokers
• A family history of clotting disorders also played a notable role

When it came to vaccination, the data told a different story. People who had received two or more doses of any Covid-19 vaccine showed no increased odds of either a heart attack or any other thrombotic event. The trend held true whether researchers looked at Covishield or Covaxin individually.

Lifestyle and health conditions are the real culprits

According to the research team, the surge in clot-related cases among young adults cannot be pinned on vaccination. Instead, it traces back to well-known and largely preventable factors , smoking habits, underlying illnesses, family medical history and a history of severe COVID-19 infection requiring hospitalisation.

Experts associated with the study stressed that public health efforts now need to pivot toward tackling these modifiable risks rather than continuing to question vaccine safety. The message from ICMR is straightforward: cutting down smoking, keeping chronic conditions under control, and keeping a close watch on people who battled severe COVID-19 could do far more to prevent future heart attacks than any concern over vaccination ever could.

The takeaway

For millions of Indians who took Covishield or Covaxin and have since worried about long-term heart risks, this study offers solid, data-backed reassurance. The evidence points away from the vaccine and squarely toward lifestyle choices and pre-existing health issues as the real factors behind clotting events in young adults.
Here are 5 FAQs based on the study:

1. Do Covishield or Covaxin increase the risk of heart attacks in young adults?

No. The ICMR study found no association between receiving two or more doses of either vaccine and increased risk of heart attacks or other thrombotic events in adults aged 18–45.

2. Who conducted this study and how large was it?

The study was led by ICMR's National Institute of Epidemiology, in collaboration with Christian Medical College, Ludhiana, and PGIMER, Chandigarh. It covered 25 tertiary care hospitals across India and analysed 432 heart attack cases and 767 cases of any thrombotic event, compared against matched controls.

3. If not vaccines, what actually causes heart attacks and clotting in young people?

The study identified smoking, existing health conditions, a family history of clotting disorders, and a past history of clotting events as the main risk factors and not vaccination.

4. Does severe past Covid-19 infection increase the risk of clotting events?

Yes. The study found that prior hospitalisation due to severe Covid-19 infection was linked to a higher risk of thrombotic events, unlike vaccination itself.

5. Was the finding the same for both Covishield and Covaxin?

Yes. When analysed separately, both vaccines showed similar results: no increased risk of heart attacks or thrombotic events tied to vaccination.