CDC acknowledges a likely link between COVID-19 vaccines and heart inflammation for young men, but says it's 'extremely rare' and the Delta variant is a bigger threat

• Myocarditis, a heart inflammation, has affected 0.004% of men aged 12-29 after their second shot of a COVID-19 vaccine.
• CDC advisors met Wednesday and acknowledged a likely link between COVID-19 vaccination and myocarditis in young men.
• But myocarditis risk from COVID-19 is much higher, especially with the Delta variant in play.

The nation's top doctors and nurses are near unanimous in their agreement that the COVID-19 vaccines authorized for use in the US are both effective and safe - even for young teenage boys who may, in rare cases, experience a type of heart inflammation called myocarditis, prompting chest pain after vaccination.

On Wednesday, an advisory group of experts independent to the CDC spent hours discussing and dissecting data on reports of myocarditis and pericarditis (heart swelling) in people under 29 years old who've been vaccinated against COVID-19 in the US.

The rate of such reports, while tiny, has been highest among young men, after their second dose of Pfizer or Moderna's mRNA vaccines. 434 cases of myocarditis have been documented in males from 12-29 years of age, in the 21 days after their second shot. That's a rate of about 0.004%, among more than 10 million vaccinated in that same age group nationwide.

But there's also a link between COVID-19 infections and myocarditis, and it's younger men who face the higher risk of death from COVID-19, according to data the advisory group reviewed.

At the end of the discussion, the CDC, the Department of Health and Human Services (HHS), and 15 more public health organizations released a joint statement, that said: "The facts are clear: this is an extremely rare side effect, and only an exceedingly small number of people will experience it after vaccination."

A rare event that resolves quickly

Even for these young men "this is still a rare event," the CDC's Dr. Tom Shimabukuro from the COVID-19 vaccine safety team said at the meeting, stressing that their cases typically resolve quickly.

"Most cases are mild, and individuals recover often on their own or with minimal treatment," the joint statement also read. "In addition, we know that myocarditis and pericarditis are much more common if you get COVID-19, and the risks to the heart from COVID-19 infection can be more severe."

Dr. Eliot Peyster, a cardiologist at the University of Pennsylvania, previously told Insider that the incidence of myocarditis from a vaccine is about "100 times lower than the incidence when you actually get [a COVID-19] infection."

The advisory group weighed the risks and benefits of vaccination to young men, and determined that benefits of vaccination clearly outweigh risks, even for males from 12-17 years old.

While there could be an additional 56 to 69 cases of myocarditis in this group, the advisors looked at forecast data that found vaccines could prevent 5,700 additional COVID-19 cases, 215 hospitalizations, 71 ICU admissions, and two deaths over 120 days.

What to do about second doses

The only group the CDC advised some caution for in administering second doses was young men who've had myocarditis after their first vaccine dose. They may want to defer a second dose, or discuss the situation with their doctor first.

For everyone else, medical professionals are stressing now's the time to get vaccinated.

The Delta variant, now responsible for more than 20% of sequenced cases in the US, is spreading much slicker and faster than other versions of the coronavirus have.

"With the troubling Delta variant increasingly circulating, and more readily impacting younger people, the risks of being unvaccinated are far greater than any rare side effects from the vaccines," the joint statement continued.

"If you get COVID-19, you could get severely ill and be hospitalized or even die. Even if your infection is mild, you or your child could face long-term symptoms following COVID-19 infection such as neurological problems or diminished lung function."