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Myocarditis is often mild, contrary to online claims

November 18, 2021 GMT

CLAIM: Myocarditis can’t be mild and it’s an irreversible condition. Once the heart muscle is damaged, it cannot be repaired by the body. Within five years of diagnosis, the death rate from myocarditis is 50%.

AP’S ASSESSMENT: False. Myocarditis, inflammation of the heart muscle, is a mild, temporary condition in the vast majority of cases, according to experts. Irreversible scarring may occur rarely in a severe case, but even then, it may be possible for the heart muscle to heal with treatment. Experts say claims that patients with myocarditis have a high mortality rate are incorrect and misinterpret the scientific literature on the condition.

THE FACTS: Misinformation about myocarditis has been spreading online in recent weeks by social media users sharing false claims about COVID-19 vaccines.

“Myocarditis is irreversible. Once the heart muscle is damaged, it cannot be repaired by the body,” states one widely shared Facebook post. “Myocarditis has a 20% fatality rate after 2 years and a 50% fatality rate after 5 years,” it continues.

The Facebook post shows a screenshot of an article written by Edward Hendrie for his blog Great Mountain Publishing, which describes itself as a Christian publishing ministry and “watchman to warn the world of the rising spiritual peril.”

Hendrie told The Associated Press his statistics around myocarditis came from an academic article co-authored by Dr. Michael Kang, health sciences assistant clinical professor at University of California Riverside School of Medicine.

Kang, contacted by the AP, said Hendrie was misrepresenting the figures used in his article, which was published in October 2017, well before the COVID-19 pandemic. It was written “as a general review of viral myocarditis and does not pertain to vaccine induced myocarditis,” Kang said.

With regards to the myocarditis death rate, Kang said his article was referencing the most severe forms of myocarditis.

Those numbers pertain to smaller, older studies, in which patients had extreme forms of the disease, “not what we are seeing with the covid19 vaccine,” Kang said in an email.

A Twitter post by Aaron Kheriaty, a professor of psychiatry at the University of California, Irvine, which circulated on Monday, stated, “There is no such thing as ‘mild’ myocarditis.” Kheriaty is currently on leave for non-compliance with the university’s vaccination requirements, according to his Twitter page and Substack.

Kheriaty, asked for evidence to support his claim, responded, “Saying ‘mild myocarditis’ is like saying ’mild heart attack.” He added that myocarditis is “always medically serious, even on the mild end of the spectrum.”

But cardiologists and medical professionals refuted that assertion, and said in many cases myocarditis is in fact both mild and reversible.

“The majority of myocarditis is mild and indeed reversible,” said Dr. Eric Adler, professor at the University of California San Diego School of Medicine who specializes in advanced heart failure. He said a majority of individuals with myocarditis — about 70% — have no symptoms or mild symptoms that resolve completely.

“Myocarditis by definition is inflammation, which is usually reversible,” said Dr. Leslie Cooper, chair of the Mayo Clinic Department of Cardiovascular Medicine in Florida.

Kang noted that some patients with myocarditis don’t experience symptoms and don’t seek out treatment. “You will never be able to count them because they never actually came in,” he said.

Severe damage and scarring can occur in a smaller amount of cases, experts said.

“Myocarditis can lead to ‘irreversible’ scarring but only in a minority of overall cases,” said Cooper.

But Adler said there are treatment options which can help recover heart tissue even in severe cases.

“Though dead heart tissue is indeed felt to be non-recoverable there are lots of examples of damaged hearts that recover to normal function over time or with medical therapy,” said Adler.

Very rarely, teens and young adults given the Pfizer or Moderna vaccines have experienced myocarditis. The condition has mostly affected young men and teen boys, and they tend to recover quickly. After intense scrutiny, U.S. health authorities concluded the vaccine’s benefits outweigh that small risk, the AP reported.

“The facts are clear: this is an extremely rare side effect, and only an exceedingly small number of people will experience it after vaccination. Importantly, for the young people who do, most cases are mild, and individuals recover often on their own or with minimal treatment,” read a statement issued last June by top U.S. government health officials, medical organizations, laboratory and hospital associations.


This is part of AP’s effort to address widely shared misinformation, including work with outside companies and organizations to add factual context to misleading content that is circulating online. Learn more about fact-checking at AP.