Key takeaways:
The flu vaccine can keep toddlers from developing severe flu illness and needing care in the hospital.
Mild flu shot side effects are common among toddlers. The most common flu shot side effects in toddlers are redness and pain at the injection site.
Flu shot side effects go away on their own, and most toddlers don’t need any medication or special treatment.
Cold and flu season can seem like a never-ending parade of illnesses, especially if you have a toddler at home. Thankfully, flu vaccines can lower your family’s risk of yet another illness during those winter months. The flu shot is available to everyone ages 6 months and older.
Flu vaccines can lower the risk of getting the flu and help protect children from severe complications, including hospitalization. The flu shot can also lower a young child’s risk of needing emergency care or hospitalization if they get the flu.
But some parents and caregivers are hesitant about flu shot side effects. The good news is that most toddlers experience only mild side effects when they get the flu vaccine — if they experience any at all. Here’s what you should know about the most common flu shot side effects in toddlers and how to keep your little one comfortable after their vaccine.
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What are the side effects of the flu vaccine?
The flu vaccine is safe. But there are many myths and urban legends about the flu shot. Fortunately, most of these aren’t true. For example, the flu shot can’t make you sick. And you can’t “catch the flu” from the flu shot either.
But just like any medicine, the flu shot can cause side effects in kids. The following are four side effects to be aware of.
1. Pain
Pain or tenderness at the injection site is the most common side effect in toddlers. This happens because the injection causes a temporary inflammatory response in the area.
You can help soothe soreness with an ice pack. Place the ice pack on your child’s arm for about 5 to 10 minutes a few times throughout the day after they get their flu shot. Make sure to wrap ice or ice packs in a cloth before placing it on your child’s skin. You can also give your child’s arm a gentle massage before they go to sleep.
2. Redness
Skin redness around the injection site is another common side effect after the flu vaccine. Many parents and caregivers worry that this can be a sign of infection. But it’s actually an injection site reaction. An injection site reaction develops because the vaccine can irritate your skin or the tissue underneath your skin. Sometimes, the vaccine can trigger an immune reaction that makes your skin turn pink or red.
Skin redness often develops a few hours after your toddler gets their vaccine. Sometimes, the redness doesn’t appear until a day or two later. Most toddlers aren’t bothered by this side effect, so you don’t have to do anything to help the redness go away. And the skin will usually go back to its normal color within a few days.
Add GoodRx as a trusted source on GoogleAdd GoodRx as a trusted source3. Fever
Some toddlers develop a fever after the flu vaccine, though fever is a less common side effect, especially when the flu vaccine is given alone. When a fever does occur, it usually starts within a day or two after the vaccine and can reach about 102°F. A fever after vaccination is a sign that your child’s immune system is responding to the vaccine.
When fever occurs, it usually lasts less than 24 hours. Call your child’s primary care provider if the fever is high, lasts longer than 48 hours, or your child seems unusually ill or uncomfortable.
You don’t need to treat a fever from the flu shot. But if your child is uncomfortable or irritable, you can try over-the-counter (OTC) fever relievers like children’s acetaminophen (Children’s Tylenol) or children’s ibuprofen (Children’s Motrin).
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4. Irritability
Some toddlers can get cranky after receiving the flu vaccine. This is usually from soreness or pain in their arm where they got their flu shot. Fevers can also make your child irritable. Treating your toddler’s pain and fever can help ease their irritability too. Most toddlers will be back to their usual selves within a day. Call your child’s primary care provider if your toddler is still more cranky than usual the next day.
5. Fatigue
Some toddlers may seem more tired or sleepy than usual after getting the flu vaccine. They may have less energy or want to rest more than they normally do. This is usually mild and goes away within a day or two. Let your child rest and make sure they’re getting enough fluids.
Can you give a toddler Motrin or other medicine after a flu shot?
Yes, if your child has muscle soreness, fever, or crankiness, it’s OK to give them acetaminophen or ibuprofen. Make sure to follow all dosing instructions on the packaging. Your child’s primary care provider can also provide you with dosing information if you’re not sure what dose to give your child.
But there are ways to help your child’s symptoms without using medication. If you prefer to avoid medication, you can try cold compresses to ease soreness and encourage your child to get plenty of rest.
It may seem like a good idea to give your child a dose of ibuprofen or acetaminophen before their flu shot. But some studies suggest that giving these medications may lower the body’s ability to respond to the vaccine. Most experts urge parents and caregivers not to give a dose of pain and fever reducers before a vaccine. But rest assured that giving these medications after a vaccine hasn’t been shown to affect your child’s immune response.
When should you see a healthcare professional about flu shot side effects?
Severe vaccine reactions are very rare. Call 911 or seek emergency medical care if your child develops signs of a severe allergic reaction, such as:
Difficulty breathing
Wheezing
Voice changes (hoarseness)
Swelling of the face, tongue, or neck
Hives
Dizziness, weakness, or fainting
Fast heart rate
Loss of skin color or paleness of the skin
In rare cases, Guillain-Barré syndrome has been reported after flu vaccination. If there’s an increased risk, it’s very small: about 1 to 2 additional cases per million doses.
Symptoms of Guillain-Barré syndrome include:
Pins and needles, tingling, or burning sensation in your hands or feet
Weakness
Trouble feeling touch
Seek immediate medical care if you notice any new or worsening weakness, trouble walking, or difficulty moving the arms or legs.
Can the flu vaccine cause febrile seizures?
Febrile seizures are seizures triggered by a fever. They can happen in young children, usually between 6 months and 5 years old. Some studies have found a small increase in the risk of febrile seizures after flu vaccination, while others haven’t.
Other research found that the flu vaccine alone doesn’t increase the risk for febrile seizures. But giving it at the same time as another vaccine, especially the pneumococcal (PCV) vaccine, can increase the risk.
More recent safety monitoring has also detected a small increase in febrile seizures after the flu vaccine alone. The risk appears to be highest during the first day after vaccination. However, the increase is very small — measured in only a few dozen additional febrile seizures per million vaccine doses. The risk can also vary depending on the flu vaccine formulation and the flu season.
It’s also important to remember that flu illness itself can cause febrile seizures. The risk of a febrile seizure is much higher with influenza infection than with flu vaccination.
Frequently asked questions
Yes, experts like the American Academy of Pediatrics (AAP) recommend the flu shot for all children ages 6 months and older. Vaccination is the best way to protect young children from flu and its complications.The AAP also notes that children without medical contraindications can get any type of flu vaccine that’s appropriate for their age and health.
Some toddlers need 2 doses of the flu vaccine, while others need just 1. Children ages 6 months through 8 years may need 2 doses if they haven’t had at least 2 flu vaccine doses in the past. The 2 doses should be given at least 4 weeks apart. Children who have already had at least 2 flu vaccine doses usually need just 1 dose each flu season. Your child’s healthcare professional can tell you how many doses your toddler needs.
Yes, experts like the American Academy of Pediatrics (AAP) recommend the flu shot for all children ages 6 months and older. Vaccination is the best way to protect young children from flu and its complications.The AAP also notes that children without medical contraindications can get any type of flu vaccine that’s appropriate for their age and health.
Some toddlers need 2 doses of the flu vaccine, while others need just 1. Children ages 6 months through 8 years may need 2 doses if they haven’t had at least 2 flu vaccine doses in the past. The 2 doses should be given at least 4 weeks apart. Children who have already had at least 2 flu vaccine doses usually need just 1 dose each flu season. Your child’s healthcare professional can tell you how many doses your toddler needs.
The bottom line
Getting your toddler vaccinated against the flu can help protect them from serious flu illness and complications. The flu shot can cause side effects — such as pain, fever, fatigue, and irritability. These are usually mild and short lived though. Rest, fluids, and comfort can help your child feel better. And over-the-counter (OTC) pain and fever relievers can help if your child is uncomfortable.
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References
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Centers for Disease Control and Prevention. (2023). Flu vaccine safety.
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Centers for Disease Control and Prevention. (2024). Possible side effects from vaccines.
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Shahrizaila, N., et al. (2021). Guillain-Barré syndrome. Lancet.
Tse, A., et al. (2012). Signal identification and evaluation for risk of febrile seizures in children following trivalent inactivated influenza vaccine in the Vaccine Safety Datalink Project, 2010-2011. Vaccine.
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