Heart Arrhythmia After COVID-19 Vaccine: a Very Rare Side Effect

What the research says

Data from the Centers for Disease Control and Prevention (CDC) shows that higher than normal cases of heart inflammation have been reported in the United States after COVID-19 vaccination with the Pfizer-BioNTech or Moderna vaccines.

These heart issues occurred mostly in males between ages 12 and 39 after they received the second dose of the vaccine, usually within a few days of receiving the vaccine. This side effect hasnt been observed in people who received the Johnson & Johnson vaccine.

The Pfizer-BioNTech and Moderna vaccines are messenger RNA (mRNA) vaccines. These vaccines contain genetically engineered mRNA that teaches your cells how to create antibodies capable of fighting the coronavirus that causes COVID-19.

Traditional vaccines, like the Johnson & Johnson COVID-19 vaccine, contain genetic material from the virus, which also helps your body create antibodies.

A 2021 analysis of CDC data found that people ages 12 to 39 who received their second COVID-19 mRNA vaccine had about a 13 in 1 million chance of experiencing heart inflammation. In other words, this side effect is exceedingly rare.

Another 2021 study involved people ages 16 and up who were vaccinated against COVID-19. It also found slightly increased risks of heart inflammation after participants first and second doses of COVID-19 vaccines in the first 28 days after vaccination. This research included the Oxford-AstraZeneca vaccine as well as the Pfizer-BioNTech and Moderna vaccines.

This risk of myocarditis did appear to be a bit higher after a second dose of the Moderna vaccine not the other vaccines studied and was only observed in people younger than 40.

Even though arrhythmias are sometimes associated with myocarditis, no direct association was found between arrhythmia and COVID-19 vaccination.

Vaccination for people with preexisting heart conditions

The American Heart Association recommends that anyone with heart disease get vaccinated against COVID-19 as soon as possible. This is because theyre at a much greater risk of heart-related complications from the coronavirus than they are from any COVID-19 vaccine.

However, if you or your child has experienced myocarditis after a vaccine before, discuss your options with your doctor before getting vaccinated.

What are the symptoms of heart arrhythmia?

Arrhythmia doesnt always cause symptoms thats why youll sometimes hear it called asymptomatic.

But possible symptoms can include:

  • chest pain
  • shortness of breath
  • feeling like the heart is fluttering or pounding (palpitations)
  • rapid heartbeat
  • slow or irregular heartbeat

A 2021 study suggests that most people suspected to have myocarditis after COVID-19 experienced chest pain about 2 or 3 days after the second dose of a COVID-19 mRNA vaccine.

Arrhythmia during COVID-19

Arrhythmias are more often seen after developing COVID-19 than after vaccination.

In small studies conducted in Wuhan, China, during the initial outbreak of COVID-19, arrhythmias occurred at a rate of 16.7% of people hospitalized with COVID-19, with 44.4% of those who were hospitalized being treated in the intensive care unit (ICU).

A retrospective 2021 study of 3,970 COVID-19 admissions at Mount Sinai Hospital in New York City found that atrial fibrillation and atrial flutter (AF/AFL) happened in 10% of study participants. AF/AFL was also associated with a 46% higher risk of death compared with 26% of study participants who had no arrhythmias.

Viral infection is the most common cause of inflammation in the heart muscle in children. Children who develop myocarditis after COVID-19 also typically experience a more severe case than if it happens after a COVID-19 vaccination.

Heart complications can occur even after you recover from COVID-19.

Common vaccine side effects

Heart problems are a very rare side effect of COVID-19 vaccines.

More common side effects are mild and temporary, including:

  • fever
  • pain and soreness at injection site
  • fatigue
  • headache
  • chills
  • body aches

These side effects occur as the vaccine triggers a response from your immune system. In other words, these side effects mean the vaccine is doing its job.

Is the COVID-19 vaccine still effective?

When first studied in earlier coronavirus variants, COVID-19 vaccines were shown to be roughly:

  • 95% effective at preventing coronavirus infection
  • 94% effective at preventing COVID-19 hospitalizations and deaths among fully vaccinated adults

Yet viruses constantly change. Several new variants have emerged since the novel coronavirus first appeared.

But even though the first COVID-19 vaccines arent as effective at preventing infection by the Delta or Omicron variants, they offer significant protection against these variants by reducing your risk of:

  • severe illness
  • hospitalization
  • death

People who are fully vaccinated and received a third booster have the highest level of protection against severe disease and hospitalization.

The CDC still recommends that everyone ages 6 months and older get vaccinated against COVID-19 even if you are immunocompromised unless you have a history of a severe allergic reaction to a previous dose or to a component of the vaccine.

Talk with a doctor if youre still unsure about getting a COVID-19 vaccination for you or your child.

The takeaway

Heart issues like myocarditis and arrhythmia are extremely rare but potentially serious side effects of mRNA COVID-19 vaccination, particularly in young males.

But getting COVID-19 is much more likely to trigger heart inflammation than the vaccine.

The CDC strongly recommends that everyone receive a COVID-19 vaccine. Talk with a doctor if youre concerned about the risk versus benefits of vaccination.