What Are the Side Effects of the COVID-19 Vaccine in Kids? And How to Get Relief

child vaccine

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Key Takeaways

  • COVID-19 vaccines side effects are generally mild to moderate in children.
  • The most common side effects are pain at the injection site, fatigue, and headaches.
  • Side effects can be effectively managed with over-the-counter medications and at-home remedies.

The COVID-19 vaccines for kids aged 5-11 are finally here! The CDC officially approved Pfizer’s pediatric vaccines on November 2nd, and since then, over 2.6 million kids —and counting!—have received their first dose.

My nine-year-old son received his first dose within a few days of the vaccine being approved. He doesn’t enjoy getting shots but was motivated by the promise of getting to do more higher-risk activities as soon as he’s fully vaccinated. A plan to go to his favorite restaurant is already in the works! He’s happy to reduce his chance of infecting others, and also really hoping his shot means that school will be a little more normal soon.

Although our family was ready to get on board with the vaccine as soon as possible, I know many families aren’t in that same place. As I talk to friends and fellow parents, one of the top concerns they have is the potential side effects of the vaccine. After all, many of us remember being strongly affected by some of our own vaccine side effects, particularly after our second dose.

Thankfully, the data show vaccine side effects among kids are generally mild to moderate, and no severe side effects were found among the 1,517 children who received the vaccine in the Pfizer trial. Verywell Family caught up with some experts in the field to help parents better understand what side effects kids are likely to experience after the vaccines—and most importantly, what parents can do to help their kids feel better.

Side Effects of Covid-19 Vaccine For Kids

So far, what we know about the vaccine side effects for kids comes from the trial study data released by Pfizer. A total of 2,268 children participated in this trial, with 1,517 children receiving the vaccine, and 751 receiving a placebo. Children participating in the trial received 1/3 the dose that adults and teens have received. Your child will be receiving this smaller dose as well.

Among the children receiving the vaccine, there were no severe reactions or side effects, says José Mayorga, MD, Executive Director, UCI Health Family Health Center. There were also no severe reported allergic reactions, including no cases of anaphylaxis, he adds. Importantly, there were no reports of myocarditis or pericarditis, a severe, but manageable side effect that has been reported mainly among young men receiving mRNA vaccines like the Pfizer vaccine.

It’s likely reassuring for most parents to hear that there were no severe side effects among trial participants. But if there are any side effects at all, we parents want to know all the details so that we can prepare ourselves, and our kids. Do vaccine side effects mean missed days of school? Will our kids be uncomfortable or feel sick?

Let’s take a look at the most common and less common side effects, and what to know about them.

Most Common Side Effects

The trial data found that the most common side effects in kids were pain on the arm where the injection had taken place, with 71 to 74% of children experiencing this. After that, feeling tired was the next most common side effect, affecting 39% of kids. Headache was also somewhat common, with 28% of kids experiencing one. Redness (19%) and swelling (15%) at the injection site were also relatively common.

Less Common Side Effects

The good news is that some of the more flu-like symptoms—the ones that make kids say, “I feel sick!”—were less common. Only 8% of kids reported having fevers after vaccination, 5% had diarrhea, and 2% experienced vomiting. 10% of kids had the chills, 12% experienced muscle pain, and 5% had joint pain.

First Shot vs. Second Shot

As was the case for adults, kids had a tougher time with systemic side effects (fever, feeling generally unwell) after their second dose of vaccine. Lowell Gordon, MD, Medical Director and Pediatrician at Families Together of Orange County Community Health Center, explains that this isn’t because children are getting a different dosage of vaccine for their second dose, but because of how their immune system reacts the second time.

“More side effects may be felt after the second shot because the immune cells from the first shot are ready to respond more quickly and more aggressively the second time around,” says Dr. Gordon. But this is a good thing, he explains. “This tells us that the body is making antibodies in response as intended,” Dr. Gordon assures.

How Long Do the Side Effects Last?

Kristina Deeter, MD, a pediatric intensivist and specialty medical officer for pediatric critical care medicine at Pediatrix Medical Group, says that parents should expect the side effects—if your child gets them—to last a few days.

That said, Dr. Deeter says that if you have any concerns about side effects affecting your child, and perhaps limiting their activities, it might be a good idea to schedule your child’s vaccine at a time when you might be able to stay home with them, should they have stronger side effects. “Try to plan the vaccination on a Friday so you can take the weekend off,” she suggests.

How Do Kids’ Side Effects Compare to Adult Side Effects?

As we consider vaccinating our children, many of us are remembering the side effects we experienced after getting vaccinated against COVID. Some of us experienced quite intense side effects and needed the day off from work after our shots, particularly after the second dose.

Dr. Deeter reminds us that children aged 5 to 11 are receiving one-third the dosage that adults received. As of November 17th, over 2.6 million kids aged 5 to 11 have been vaccinated. So far, most of the reported side effects among children have been on the milder side.

“In Pfizer’s trials in this population, there were no serious adverse effects reported, including no reports of myocarditis,” Dr. Deeter says. “I would expect that kids will experience similar mild flu-like symptoms to adults that will resolve in a couple of days.”

Dr. Mayorga notes that children have generally done quite well as compared to teens and adults who received the vaccine. In fact, published data from the CDC compares vaccine side effects among the 5 to 11-year-old cohort to that of 16-25 year-olds. Overall, side effects were milder in the younger children, with teens and young adults experiencing higher rates of fevers, fatigue, headaches, chills, and muscle pain.

Tips for Managing Side Effects

It’s not likely that your child will experience very bothersome side effects, but all children are different, and some children might experience more challenging side effects than others. This may be particularly true after their second dose of vaccine.

You can rest assured, though, that there are several effective ways to soothe your child’s discomforts. Here are some doctor-approved tips.


Dr. Shanika Boyce, MD, MPH, FAAP, Pediatrician and Assistant Professor at Charles R. Drew University of Medicine and Science says that painkillers such as acetaminophen and ibuprofen can be used to relieve fever and pain. If you notice any swelling, redness, or itchiness at the injection site, you can try an antihistamine, says Dr. Boyce.

As always, make sure to contact your child's pediatrician for any dosing recommendations, and to be sure that these medications are right for your child.

Home Remedies

If your child experiences swelling, pain, or redness at the injection site, applying a cool, wet cloth can be very soothing, says Dr. Gordon. If your child develops a fever, Dr. Gordon recommends drinking plenty of fluids and dressing lightly to stay comfortable.

Dr. Deeter is a huge fan of getting some extra rest after the shot and says that chicken soup can be very helpful too (it’s not just a myth!). She recommends checking in with a pediatrician if the area where the shot was given stays red and tender for more than two days.

Addressing Parents’ Lingering Concerns

Even if you hear reassuring information about side effects, you may still have lingering fears and doubts. This is common and understandable.

Many parents are particularly concerned about long-term vaccine effects, says Dr. Deeter. Most notably, they are concerned about questions surrounding future fertility as well as genetic modifications after the vaccine, Dr. Deeter explains.

Dr. Deeter wants to reassure parents that there have been no studies showing either infertility after vaccination or evidence that the vaccine causes genetic shifts or damage.

“As pediatricians, we would absolutely never recommend a vaccine that we were concerned caused long-term side effects, especially something like infertility,” Dr. Deeter says. “There’s nothing about this vaccine that can make that modification in anyone’s body.”

In fact, many pediatricians feel so comfortable with this vaccine that they have already started eagerly giving it to their own children. Dr. Mayorga shared his own family’s story with us.

“Unfortunately, my family knows how devastating this infection can be because we have lost several loved ones to COVID-19,” Dr. Mayorga says. He decided to get his three daughters the vaccine because he was convinced it was safe and would protect his daughters against any serious effects of COVID-19.

As for his daughters’ side effects? All three of them did well; his oldest daughter had some fatigue, but she was good as new within 24 hours.

“The major 'side effect' my wife and I observed was the ice cream eating that followed,” he shares, adding, “As a doctor, but more importantly as a dad, I know getting the vaccine will help protect my daughters and they will enjoy more things without worrying about getting COVID-19.”

What This Means For You

All the doctors we spoke to agreed that COVID-19 vaccine side effects in children are generally mild and manageable. They also assured parents that any uncomfortable side effects can be effectively managed with over-the-counter medication, and at-home comforts like cold compresses, rest, and extra fluids.

If you have any questions about the vaccines or their side effects, you should contact your child’s pediatrician. They know your child and their health history and can address any continued questions or concerns you may have.

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2 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Barnett E, Domachowske J, Gurtman A, et al. Evaluation of the BNT162b2 Covid-19 Vaccine in Children 5 to 11 Years of Age. New England Journal of Medicine. 2021. doi:10.1056/NEJMoa2116298

  2. Gurtman A. BNT162b2 (COVID-19 Vaccine, mRNA) Vaccine in Individuals 5 to <12 Years of Age. Centers for Disease Control and Prevention website. Updated November 2, 2021. 

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