Do COVID-19 Vaccines Cause Myocarditis?
Jun 23, 2021

NOTE: This post was last updated on December 23, 2021. We will continue to update it as more information becomes available.

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In November 2021, the CDC’s advisory group (ACIP) met to review the cases of myocarditis and pericarditis in teenagers and young adults who got an mRNA COVID vaccine, like the ones by Pfizer and Moderna. Most of the cases investigated so far have been mild and short-lived, but the reports have made folks understandably concerned. Here’s what we know so far and why getting vaccinated is likely still the safer choice.

First, what are myocarditis and pericarditis?

Myocarditis and pericarditis are medical terms for inflammation in or around the heart. The terms might sound scary, but cases of myocarditis and pericarditis can be mild and treatable. In fact, of those who developed the heart conditions after getting vaccinated, at least 74% (or 3 in 4) have made a full recovery.

Symptoms of myocarditis and pericarditis include: 

• Chest pain
• Difficulty breathing
• Feeling like your heart is beating too hard or too fast

If you or a family member start to feel any of the above within a week or so of getting the Pfizer or Moderna COVID-19 vaccine, talk to a healthcare provider right away.

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Have you read:

• Does the COVID-19 Vaccine Cause Blood Clots?
• Can COVID-19 Vaccines Alter Your DNA? The Vaccine Mom Explains.

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Can COVID vaccines cause myocarditis or pericarditis? 

It looks like the mRNA vaccines could trigger these heart conditions, but the chances of it happening to any one person are really small.

Researchers are still investigating, but it looks like more vaccinated teens and young adults are developing myocarditis and pericarditis than you’d expect to see in that age group. Young men under 30 years old, in particular, seem to be more at risk. And the conditions are more common after the second dose of the COVID vaccine compared to the first. (Health experts haven’t seen the same pattern after the Johnson & Johnson COVID vaccine, which is made using a different technology.)

Experts will continue to investigate, but so far the risk of getting these heart conditions after COVID vaccination looks rare. Among people under 40 years old getting their second dose (the group at highest risk for developing these conditions after the vaccination), the estimated rate ranges from about 4.2-39.9 cases per million. To put that into perspective, this is way lower than a person’s lifetime chance of, say, getting struck by lightning.

Even so, health experts are taking the reports of myocarditis very seriously, like they do with anything serious that could be linked to vaccines, and will continue to weigh how this possible risk compares to the dangers of COVID-19.

Getting sick with COVID-19 can cause myocarditis too — among other things. 

Young adults and teenagers might not be as likely to die from COVID-19 as older adults, but they aren’t naturally immune. Thousands of people under 30 years old in the U.S. have died from the virus. Many more have landed in the hospital or live with long-term symptoms, commonly called “long COVID.” The virus that causes COVID can damage vital organs, including the heart. Study after study has found that the virus can often cause serious or long-term harm to the body, including in those who were healthy before getting COVID.

Some kids and teenagers can also develop Multisystem inflammatory syndrome in children, or MIS-C. MIS-C (and a similar condition in adults called MIS-A) isn’t common, but it can be very dangerous. Vital organs like the heart, lungs, and brain get severely inflamed, putting kids at risk of lifelong health issues or death.

Researchers are still trying to figure out why COVID hits some children harder than others. But preteens and teens seem to be more likely than younger kids to get seriously sick from the virus in general, which is why health experts strongly encourage those 12 years and up to get vaccinated.

Bottom line: Vaccination is still the safer choice.

Health experts will continue to investigate reports of heart issues after mRNA COVID vaccines. But the research so far points to cases being largely mild and rare — especially compared to COVID-19. The CDC also recommends receiving one of the mRNA vaccines, instead of the Johnson & Johnson vaccine, due to their better safety and effectiveness.

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For more info, check out: 

• Vaccinate Your Family: Questions and Answers About COVID-19 Vaccines
• American Academy of Pediatrics’ HealthyChildren.org: Does the COVID-19 vaccine cause myocarditis?
• Your Local Epidemiologist: An update on myocarditis cases

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