New Delhi: There is no association between the Covid-19 vaccines used in India — Covishield and Covaxin — and increase in the risk of heart attacks, according to an observational study which emphasises the protective effect of the jabs.

The research, published recently in the journal PLOS One, determined the impact of COVID-19 vaccination on mortality following acute myocardial infarction (AMI) or heart attack.

Among the vaccinated group, 1,047 (96 per cent) had received two doses of the vaccine while 39 (4 per cent) had received only a single dose.

“Our study found that vaccines used in India are safe. There was no association of vaccination in India with heart attack. In fact, the study found that there were less chances of death after heart attack in vaccinated individuals,” Mohit Gupta, who led the study, from G B Pant Hospital, told PTI.

The adverse effects (AEs) of COVID-19 vaccines have mostly been mild, transient and self-limiting. However, concerns have been raised regarding the cardiovascular adverse effects of these vaccines.

Any side effect can have catastrophic effects especially in large densely populated countries such as India, the authors noted.

In all the enrolled patients, data regarding the patient’s vaccination status including details on type of vaccine, date of vaccination and adverse effects were obtained.

The researchers found that the analysis did not show a specific clustering of AMI at any particular time post vaccination, suggesting there was no significant association between COVID-19 jabs and heart attacks.

On 30-day follow-up, all-cause mortality occurred in 201 (12.7 per cent) patients with adjusted odds of mortality being significantly lower in the vaccinated group.

Similarly, at six months of follow-up, the vaccinated AMI group had lower odds of mortality as compared to the non-vaccinated group.

COVID-19 vaccines showed a decrease in all-cause mortality at 30 days and six months following AMI, according to the study.

However, increasing age, diabetics and smokers had a higher risk of 30-day mortality, the researchers said.

“Findings of our study showed that the 30-day and six months all-cause mortality risk was significantly lower in the vaccinated subjects as compared to the unvaccinated population,” the authors of the study said.

This study is the first to be conducted among a larger population of AMI patients which has shown COVID-19 vaccine to be not only safe but also have a protective effect in terms of reduction of all-cause mortality both on short term as well as at six months of follow-up, the authors of the study said.

They noted some limitations, saying that this was a single centre retrospective study, and the findings need to be validated in further larger studies from different ethnic groups.