Cardiologists weigh in on whether COVID-19 or vaccines pose a greater risk of heart problems

Nearly three years since the start of the COVID-19 pandemic, a growing body of research is showing links between COVID-19 and heart-related problems, particularly in young people.

One study published in the scientific journal Nature Medicine on Feb. 7 found that rates of conditions such as heart failure and stroke were substantially higher in people who had recovered from COVID-19 than those who had never contracted the virus. Even people who had experienced a mild case of COVID-19 were at risk, the study found.

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“Overall, when you sort of zoom out and look at all the evidence, it does look as if COVID, as a rule, as an illness, regardless of its severity, does increase the risk of developing cardiac complications,” cardiologist Christopher Labos told CTV News Channel on Feb. 11. “And it seems to affect all people of all age brackets.”

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In September last year, a study led by Cedars-Sinai hospital in Los Angeles found that while the virus was associated with an increase in heart attacks in all age groups, those between the ages of 25 and 44 saw the highest increase. Heart attack rates in this age group increased 29.9 per cent, compared to 19.6 per cent for those aged 45 to 64 and 13.7 per cent for those aged 65 and over.

Labos explained the risk of developing any of a “broad constellation of (cardiac) symptoms” following a COVID-19 infection varies from one age bracket to another.

“With the older individuals, you’re seeing more heart attack and more traditional coronary artery disease,” he said. “But with younger individuals, you’re also seeing more arrhythmias, more difficulty with exercise capacity.”

Scientists are still learning about how COVID-19 affects the heart, but Labos explained many of the cardiac complications related to COVID-19 infections tend to fall into the categories of heart attacks and issues with the heart’s electrical impulses.

“So there’s more clots and more heart attacks. But there also appears to be a derangement of the electrical system. And a lot of people complain of arrhythmias, palpitations, and just an inability to sort of regulate their heart rate,” he told CTV News Channel on Feb. 22.

Despite mounting evidence that even mild COVID-19 cases can damage the cardiovascular system, some people continue to argue that COVID-19 vaccines pose a greater health risk.


Earlier this month, European news outlet AFP debunked a rumour that a photo circulating online showed a massive bronchial blood clot caused by COVID-19 vaccine. While the photo did show a blood clot in the shape of a patient’s right bronchial tree, a reverse image search conducted by AFP found it pre-dated the pandemic and was completely unrelated to vaccines.

Then, there’s the Feb. 15 letter addressed by Florida’s surgeon general to the commissioner of the U.S. Food and Drug Administration and the director of the Centers for Disease Control and Prevention.

In an official Florida Department of Health document, the state’s surgeon general Joseph Ladapo wrote to federal officials stating Florida had recorded a significant surge in adverse health effects related to COVID-19 vaccinations.

“We saw a 1,700 per cent increase in reports after the release of the COVID-I9 vaccine, compared to an increase of 400 per cent in vaccine administration for the same period,” Ladapo wrote, though he did not say during which period the reporting took place. “The reporting of life-threatening conditions increased (by) 4,400 per cent.”

Lapado also cited a “recent study” that found mRNA COVID-19 vaccines were associated with an “excess risk of serious adverse events,” including blood clotting disorders, acute cardiac injuries, Bell’s palsy and encephalitis. He said the “risk was 1 in 550” but did not say which specific risk the number referred to.

Dr. Peter Liu, chief scientific officer and vice president of research at the University of Ottawa Heart Institute, reviewed the letter and, in a telephone interview with on Thursday, said he couldn’t track down any credible evidence to support many of the claims it made.

He pointed out that the letter outlines the increase in reports of vaccine-related adverse effects in percentages only, leaving out the absolute numbers and any explanation of how those percentages were calculated.

“The interpretation of all this information gets coloured, unfortunately, and this generates a lot of misinformation,” he said. “A letter like this, which actually is not backed up by published data – making all these kind of percentage depictions of the data, and making a conclusion that is very difficult to verify – can lead to a lot of concerned people.”


While it’s true that some COVID-19 mRNA vaccines have been linked to myocarditis in rare cases — a potentially deadly inflammation of the heart muscle — studies have shown that the benefits of the vaccine still outweigh the risk of inflammation, and getting the virus has a far higher risk of inflammation compared to the vaccine.

That is also Liu’s professional opinion. Liu has studied data from Canada’s Vaccine Injury Support Program as well as data from vaccine adverse effects studies conducted in Canada, the U.S. and the U.K.. He is also part of a team following the long-term outcomes of 200 patients who reported cardiac symptoms following vaccination. Among the patients in that group who suffered from myocarditis following vaccination, he said almost all have recovered and none have died from the condition.

“From what we have published and from what we have studied, certainly, we have seen these cases, you know, relate to cardiac complications, but they’re extremely rare,” he said.

In Canada, out of 97 million COVID-19 vaccine doses administered since Dec. 14, 2020, there have been 10,582 serious adverse events reported. That is a rate of approximately 0.01 per cent. This data is made publicly available by the Government of Canada, including a breakdown of serious adverse events.

“So the general risk is extremely low,” Liu said.

Liu said there is evidence that rates of myocarditis following mRNA COVID-19 vaccination are about two to three times higher among men between the ages of 12 and 39 compared to the general population.

“This is a very interesting kind of subgroup that seem to have a higher incidence, which is about two to three times higher risk compared to the general population, and this probably has to do with how the young men’s immune system handles the vaccine,” he said.

However, he said, even among men between 12 and 29, the risk of developing myocarditis following a COVID-19 infection is higher – up to five times higher.

Given everything scientists and cardiologists have learned during the pandemic, Dr. Chris Overgaard, a fellow in the division of cardiology at the University of Toronto, agrees with Liu that the balance of benefit versus risk still resides with the vaccine.

“I think it’s disingenuous to say that vaccines are perfect, right? They’re not,” Overgaard told in a phone interview on Feb. 23. “But they have done what we hoped they would do, and they have done it very well…so the risks of severe cardiac illness with COVID-19 are far greater than the risks of the vaccine.”

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