What is myocarditis and how is it connected to covid-19 vaccines?

The CDC is currently investigating a link between the Pfizer/BioNTech and Moderna vaccinations and increased cases of heart inflammation in certain groups.

What is myocarditis and how is it connected to covid-19 vaccines?
Dado Ruvic REUTERS

The US’ vaccine rollout continues with over 140 million Americans having now received both doses of covid-19 vaccinations. However there are reports that link the mRNA shots to greater instances of myocarditis in certain demographic groups.

The Centers for Disease Control and Prevention (CDC) have confirmed that young men who have received both doses of an mRNA vaccine are experiencing higher-than-expected cases of the heart inflammation.

The US Vaccine Adverse Event Reporting System (VAERS) keep a track on all potential side effects related to vaccinations and have found that half of those reporting myocarditis are aged between 12 and 24. That group accounts for just 9% of doses administered so far.

What is myocarditis?

Myocarditis is an inflammation of the heart muscle which can affect your heart muscle and the organ’s electrical system. This can, in more extreme cases, reduce the heart’s ability to pump blood and can cause abnormal heart rhythms, also known as arrhythmias.

The cause of myocarditis is often a viral infection, but it can also stem from a reaction to a pharmaceutical or just a general inflammatory condition. In the most severe cases, the heart is prevented from pumping blood around the body and can lead to blot clots.

The CDC advise that everyone aged 12 and over should still get the covid-19 vaccine if possible and point out that covid-19 represents a far greater risk with more common severe complications. However they do suggest that vaccine recipients be on the lookout for the following symptoms which could suggest a negative reaction:

  • Chest pain
  • Shortness of breath
  • Feelings of having a fast-beating, fluttering, or pounding heart

CDC to host emergency meeting to discuss myocarditis link

VAERS has so far recorded 226 cases of myocarditis and pericarditis (a related heart inflammation) in 141 million fully vaccinated Americans. Instances of either condition are still extremely rare, but the apparent increase in cases amongst certain age groups have spurred the CDC into further action.

An advisory panel for the CDC is set to meet next week to discuss the potential link between myocarditis and mRNA vaccines. Dr Tom Shimabukuro, deputy director of the CDC's Immunization Safety Office, said that the evidence suggests that there is clearly “an imbalance there,” but stopped short of suggested that there was a causal link.

The Israeli health ministry is also investigating cases of heart inflammation and has confirmed that they will continue to research the link.