CLAIMS THAT HEART problems such as myocarditis only affect vaccinated people or that they affect vaccinated people more than unvaccinated people are contradicted by scientific data.
Misinformation about a link between Covid vaccines and myocarditis - which is the inflammation of the heart muscle, usually triggered by a virus – have been spreading since the rollout of the vaccines.
This was boosted when it emerged in 2021 that the Pfizer and Moderna vaccines carried an associated risk of the condition, particularly among adolescent boys and young men.
Anti-vaccine campaigners have frequently played up the link since, in order to undermine the rollout of Covid vaccines by claiming they are dangerous, and that authorities can therefore not be trusted on other measures such as mask-wearing and social distancing.
One example of the myocarditis claim, recently spread by Irish social media users, shows a picture of a man gripping his chest alongside the words: “Coinciditis. Myocarditis that coincidentally only affects the vaccinated.”
But while some vaccines may cause rare cases of myocarditis, it has also been shown that catching Covid-19 carries a much higher risk of developing the condition.
As a result, early research estimated that vaccination against Covid-19 is much less risky than the risks to cardiovascular health as a result of catching Covid-19.
More recent research also corroborates this: unvaccinated people suffer from serious heart problems, including death, at a higher rate than vaccinated people, even among young men, the group most likely to get myocarditis from vaccines.
Claims about vaccines and cardiovascular side-effects were prompted by the World Health Organisation announcing in Summer of 2021 that there is a likely link between Covid mRNA vaccines and the rare heart condition.
In June 2021, US medical authorities warned there was a likely link between mRNA vaccines – such as Pfizer and Moderna – and myocarditis cases among younger recipients, (though they also said the benefits of vaccines continued to outweigh the risks of not being vaccinated).
The European Medicines Agency’s pharmacovigilance committee, which tracks medicines’ side effects, also said there was a “plausible causal relationship” in a review of the data the following month.
However, the World Health Organisation later stated that most cases of myocarditis as a result of Covid vaccines were mild – and that the body continued to recommend the vaccines.
Early research on the issue estimated that vaccines might cause 2.7 cases of myocarditis in every 100,000 vaccinated people, while Covid-19 infection caused about 11 cases per 100,000 people infected.
Researchers who carried out that study also noted that the risk of “many other serious adverse events was substantially increased after SARS-CoV-2 infection”.
Other research since has corroborated the fact that there is a much higher rate of myocarditis among people after they have been infected with Covid-19 than after receiving vaccines (though also noted that vaccines had a much more severe effect on younger men).
Other later studies also found that cases of vaccine-associated myocarditis (VAM) were real, but rare. None of these studies said that rates of VAM made the vaccines dangerous, and none recommended stopping the vaccine rollouts due to the risk to people.
One of these studies noted: “Clinical outcomes among vaccinated people with myocarditis or myopericarditis were predominantly mild. We observed no readmissions, diagnoses of heart failure, or deaths among people with myocarditis or myopericarditis occurring within 28 days of mRNA-1273 vaccination.”
Those researchers also said specifically that infection with Covid-19 was an “undesirable alternative to vaccination”.
In contrast to those who say that vaccines carry a risk, there is a range of evidence that points to greater risks to health among those who are unvaccinated.
A 2022 study by the American College of Cardiology directly compared the potential negative effects of vaccination against the risks of not being vaccinated.
When it looked at young men, the group deemed most at risk of VAM, the evidence clearly signaled that vaccinating was safer.
The study found that for every 39-47 cases of VAM in vaccinated men between the ages of 12 and 29 years, 6 deaths from Covid-19, 560 hospitalisations, 138 ICU admissions and 11,000 cases could be prevented by vaccination.
It also noted that these figures may not take into account rates of Multisystem Inflammatory Syndrome in Children (MIS-C), which often appears weeks after infections and regularly requires intensive care and advanced life support, as opposed to “the generally mild course of most VAM”.
Although vaccines, including flu shots, may be associated with rare, usually mild cases of myocarditis, Covid-19 vaccines in particular provide strong protection against a disease which causes myocarditis in much greater rates, as well as other serious complications.
The Irish Heart Foundation continues to recommend that people with heart conditions receive Covid-19 vaccines, saying: “Covid infection itself can affect the heart and cause damage.
“The vaccines have been shown to be safe and there are no recorded cardiac issues other than the rare case of severe allergy/anaphylaxis.”
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