Shots became available for more than 28 million children across the nation after the Centers for Disease Control and Prevention (CDC) approved the Pfizer-BioNTech Covid vaccine for use in kids ages 5 to 11. The news offered a sense of relief to some parents who have been waiting for this moment since the start of the pandemic so many long months ago. 

But kids aren't tiny adults, meaning they can react differently to medications and vaccines, so it's understandable that some parents may be hesitant to vaccinate. However, the side effects of the Covid vaccine in kids are generally mild—and some kids may not even experience any side effects at all.

The CDC approval came after advisory panels to both the CDC and the Food and Drug Administration (FDA) overwhelmingly recommended the vaccine. After a rigorous data review, both agencies concluded that a universal vaccine for kids that prevents Covid greatly outweighs the potential side effects from receiving the shot. 

The Pfizer vaccine was found to be 90.7% effective in preventing symptoms of the virus and protecting against severe disease and the need for hospitalization. Side effects in this age group were also found to be more mild and less common than side effects in adolescents and adults. 

That’s most likely due to the smaller dosage of the pediatric vaccine, which is one-third of the dose of the vaccine for adults. Researchers identified this smaller dose as one that will still confer a powerful immune response in kids—while minimizing potential side effects. 

What are the side effects of the Covid vaccine for kids?

The most common side effects seen in the 2,268 children observed in the Pfizer trials were mild. 

Common side effects:

  • Pain at injection site (upper arm)
  • Fatigue
  • Headache
  • Muscle pain
  • Joint pain
  • Fever
  • Chills
  • Swollen lymph nodes
  • Nausea
  • Decreased appetite

These side effects are typically temporary, clearing up within 48 hours. Most occurred after the second dose rather than the first (aside from arm soreness at the injection site).

According to data submitted to the FDA, 70% of children experienced pain at the injection site, 39% experienced fatigue, 28% experienced headaches and fewer than 10% of kids experienced muscle or joint pain, fever and chills.

There were no serious side effects reported. Just like with adults, your child will be monitored for 15 or 30 minutes after getting the shot in case any allergic reactions occur.

How can I prevent side effects in my child?

The Mayo Clinic doesn't recommend giving an over-the-counter pain reliever to your child before vaccination.

However, it is OK to give your child a pain-reliever after they get a Covid vaccine—but talk to your doctor about this, too.

Is myocarditis a side effect of the kids’ vaccine?

We know from Pfizer’s clinical trial data that there were no signs of a type of heart inflammation known as myocarditis observed. But there have been cases of myocarditis and pericarditis (another type of heart inflammation involving the heart muscle lining) reported several days after the second dose of an mRNA vaccine, primarily in men between the ages of 12 and 29

Experts expect the risk of myocarditis after vaccination to be very low in this age group for two reasons: 

  • Myocarditis is more common in adolescent males and young adults than in children—and even in the 12-15 age group, the risk is estimated at 0.007%. 
  • Thanks to the smaller dosage, side effects are minimal in general, and the 12- to 15 year-old dose is three times the size of the 5- to 11-year-old dose.

In truth, the risk of getting myocarditis from Covid is much greater than from a side effect of the vaccine, shares Preeti Parikh, MD, a pediatrician and medical director at GoodRx. The virus can infect the cardiac muscle and weaken the heart and surrounding blood vessels.

While there is a very low risk of myocarditis from mRNA vaccines, it’s worth highlighting the fact that myocarditis may resolve on its own, even without treatment. But if your child has any symptoms of myocarditis (outlined below), seek medical care.

Symptoms of myocarditis

Potential signs and symptoms of myocarditis (inflammation of the heart muscle) or pericarditis (inflammation of the lining outside the heart):

  • Chest pain
  • Shortness of breath
  • Heart palpitations

If your child experiences any of the above after receiving an mRNA vaccination, call your child’s doctor.

While no vaccine is 100% effective nor completely without side effects, both the FDA and CDC ultimately determined that vaccine benefits significantly outweigh the possible risk of vaccine side effects. Of course, if you have more questions about vaccine safety, talk to your pediatrician.