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The Side Effects Kids Could Experience After the Covid-19 Vaccine

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Key Takeaways

  • Kids typically experience mild side effects, if any, from the COVID-19 vaccine.
  • Side effects should only last a few days.
  • Most side effects are easy to manage with rest.

With the Pfizer-BioNtech COVID-19 vaccine now available for kids aged 12 and over, the nation looks to a brighter future. But with the long-term benefits of vaccination sometimes comes the short-term discomfort of side effects.

Side effects are the expected yet uncomfortable reactions to a vaccine. Rest, simple pain-relieving medications, and a bit of sympathy can typically help kids bounce back quickly. 

Here, we share the common side effects reported in kids, what you can expect, and how to help your kids through the worst of it. 

Why Do We Get Side Effects?

Side effects can be common after vaccinations, and the COVID-19 vaccine is no different. Vaccines provide a tiny portion of a pathogen to the body so that the immune system learns to recognize it as a threat and build a defense against it.

Jay M. Lieberman, MD

We don’t understand why certain people have worse symptoms than others.

— Jay M. Lieberman, MD

Jay M. Lieberman, MD, infectious disease specialist, explains that side effects are simply the immune system hard at work. “A lot of the symptoms that we develop after vaccination are not a result of the virus or the vaccine per se—it's our response to it,” says Dr. Lieberman. “It's our immune system responding to that foreign invader, trying to fight it off.”

When the immune system is hard at work building this immunity, it can make your child feel a bit yucky for a few days. Every child will experience side effects differently, but don’t worry if your child experiences no side effects. The vaccine should still be working.

“We know from the studies that people who didn't develop side effects were still highly protected against the virus,” explains Dr. Lieberman. “We don't understand why certain people have worse symptoms than others.”

Managing Your Child’s Side Effects 

Side effects experienced by kids from the COVID-19 vaccine are generally mild to moderate and similar in nature to those experienced by adults. Typically, side effects can be managed with simple remedies and over-the-counter medication.

Jenna Wheeler, MD, pediatric critical care physician, reminds parents that these side effects shouldn't last long and your kids will be back in full spirits soon enough. "For the majority of children, these symptoms go away quickly in just a few days," says Dr. Wheeler. In the meantime, she recommends "supportive care," which means rest, hydration, and gentle remedies that can hopefully help them to feel a bit better.

Jenna Wheeler, MD

For the majority of children, these symptoms go away quickly in just a few days.

— Jenna Wheeler, MD

Dr. Wheeler helps outline some simple remedies that parents can use to help kids through the worst of the side effects.

Fatigue and Malaise

Fatigue means to feel tired. And malaise means to feel generally uncomfortable, ill, and miserable. The best remedy for these side effects is rest. If your child doesn’t want to sleep, this might be a good time to just let them relax on the couch with a book or a movie.

Aching Muscles and Joints

An achy body can also be treated with rest. However, every child is different. Some kids may find moving their body helps relieve the ache. If your child does need to move, try to keep their activities gentle. "Avoid strenuous activity until symptoms improve," suggests Dr. Wheeler.

If your child is particularly uncomfortable, simple over-the-counter medications such as acetaminophen or ibuprofen may help make them feel more comfortable. 

What This Means For you

Before giving your child any medication, it is important that you check with your child's healthcare provider to ensure they are safe for your child’s unique condition. It is especially important not to give your child aspirin because it can cause a potentially fatal condition.

Remember that children require medication doses based on their age and weight. Talk to your child's healthcare provider about the correct doses to offer your child.

Headaches 

Pain in or around the head and neck can make anyone feel irritable, especially kids. Sometimes a cool washcloth on your child’s forehead or a warm washcloth on their neck can help a headache. Dimming the lights and avoiding screens may also help ease the pain. It is important to ensure your child is well hydrated, so encourage regular sips of water. 

If the headache is particularly bothersome, an over-the-counter non-aspirin pain reliever can be used.

Injection Site Concerns

The area around the injection site can be sore, red, or even a little swollen for a few days. This is because of the physical insult on the tissue. “We all understand that [if] we get a scratch on the arm we see that over the next days it gets a little red as it heals,” explains Dr. Lieberman. “That’s our immune system. Our body responds with inflammation and it's a way of healing.” 

A cool pack on the site can help to reduce the discomfort of the swelling and pain. The swelling, pain, and redness are typically worse in the first day or two and should get better day by day. If it starts to look worse or begins hurting several days after the vaccine, contact your child’s healthcare provider. Worsening of these symptoms can indicate a possible infection. 

Some people have reported a delayed mild allergic reaction commonly called “COVID arm.” This is a ring-like rash around the injection site that appears several days to more than a week after the injection. This reaction is typically considered harmless but can be irritating and itchy. If you have any concerns, speak with your healthcare provider.

Cold packs may help relieve the itch temporarily. Dr. Lieberman also suggests antihistamines, which may be helpful to reduce any itch. But check with your child's healthcare provider to determine if this would be appropriate.

Chills or Fever

The body typically increases its temperature as a mechanism for fighting off pathogens. Sometimes children will feel chills prior to or during a fever.

For low-grade fevers where your child is relatively comfortable, you can encourage your child to wear lighter clothing, take regular sips of water, and rest.

Fever-reducing medications such as acetaminophen or ibuprofen may be used with the advice of your healthcare provider. You should avoid using aspirin in children for pain or fever.

When to Call the Doctor

If your child's side effects appear to get worse rather than better, speak to your child's healthcare provider. Also, if your child experiences anything different than the expected side effects, it is best to seek medical advice.

"Call your pediatrician or family doctor if you have any concerns about your child’s symptoms," advises Dr. Wheeler. "If your child has any complaints of chest pain, shortness of breath or fluttering/pounding sensation of the heart it is very important to seek medical care."

Myocarditis and Pericarditis

The Centers for Disease Control and Prevention (CDC) has received reports of myocarditis and pericarditis (inflammation of the heart) in adolescents and young adults after COVID-19 vaccination.

Even so, the potential benefits of vaccination outweigh the potential risks. The CDC continues to recommend COVID-19 vaccination to all eligible adolescents.

A Word From Verywell

It is hard to watch your child in pain and discomfort after a vaccine. Remember that you know your child better than anyone else. So if you are concerned at any point, contact your child’s doctor. 

The good news is that side effects should only last a few days. It is important to complete your child's vaccination schedule despite these side effects. Full immunity against COVID-19 is not achieved until two weeks after the second dose of the Pfizer-BioNTech and Moderna vaccines.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.

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Article Sources
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  1. Centers for Disease Control and Prevention. Understanding adverse events and side effects. Updated March 30, 2021.

  2. MedlinePlus. Fatigue. Updated April 26, 2019.

  3. MedlinePlus. Malaise. Updated February 7, 2019.

  4. Nationwide Children’s Hospital. Headaches in children. Updated March 6, 2012.

  5. Centers for Disease Control and Prevention. What to do if you have an allergic reaction after getting a COVID-19 vaccine. Updated March 4, 2021.

  6. MedlinePlus. Fever. Updated August 29, 2020.

  7. MedlinePlus. Chills. Updated February 7, 2019.

  8. Centers for Disease Control and Prevention. Possible side effects after getting a COVID-19 vaccine. Updated May 25, 2021.

  9. Centers for Disease Control and Prevention. COVID-19 vaccines for children and teens. Updated May 27, 2021.

  10. Centers for Disease Control and Prevention. Understanding how COVID-19 vaccines work. Updated May 27, 2021.