8 FluMist Side Effects You Should Know About (and How to Manage Them)

FluMist is a live flu vaccine that’s approved for people ages 2 to 49 years old. But unlike traditional flu shots, FluMist is a nasal spray. You’ll receive one or two doses, depending on your age and vaccination history. And you may even be able to give it to yourself at home. But what about side effects?

Knowing what to expect can help lessen vaccine-related anxiety. Let’s take a look at possible FluMist side effects, how to manage them, and when to be concerned.

FluMist side effects at a glance

The lists below cover common and rare FluMist side effects reported in clinical studies. Some FluMist side effects, such as fever and headache, overlap with those caused by flu shots. But because it’s a nasal spray, FluMist also has other side effects to consider.

Mild FluMist side effects include:

• Runny nose

• Stuffy nose

• Fever

• Sore throat

• Headache

• Muscle aches

• Chills

• Fatigue

• Reduced appetite

Rare, but serious FluMist risks and side effects include:

• Wheezing or trouble breathing

• Allergic reactions

• Guillain-Barré syndrome

Let’s take a look at eight Flumist side effects in greater detail.

Good to know: You cannot get the flu from the FluMist vaccine. Some FluMist side effects mimic symptoms of the flu. But this is because the vaccine is activating your immune system so it can make antibodies against the flu virus. These FluMist side effects are mild and short-lasting, unlike the flu itself. They aren’t a sign that the vaccine is making you sick — they’re a sign that the vaccine is working properly.

1. Runny or stuffy nose

Nasal side effects — particularly runny or stuffy nose — are the most common FluMist side effects. And they’re unique to FluMist compared to a flu shot. That’s because you spray FluMist into your nose, which can cause minor irritation for some people.

Nasal side effects are most likely to occur within a few days after receiving FluMist. They typically go away on their own within a day or two. Children receiving two doses may be more likely to experience nasal side effects after the first dose compared to the second dose.

Contact your healthcare team if you experience a runny or stuffy nose that doesn’t go away after a week. It’s possible that something other than FluMist, such as an infection, is causing your symptoms.

2. Fever

You may experience a low-grade fever after receiving FluMist. Children are more likely to develop a fever than adults. But it’s typically a sign that the vaccine is working, and it should go away after a day or two. 

If needed, you can take acetaminophen (Tylenol) or another fever-reducer to help. It’s also a good idea to drink plenty of fluids to avoid dehydration.

Seek medical care if the fever is high, lasts more than a day or two after you receive FluMist, and/or is accompanied by other symptoms (such as a cough or skin rash). These could be signs of an infection, rather than side effects related to the vaccine

3. Sore throat

Among adults, sore throat was one of the most common side effects reported after receiving FluMist in clinical trials. This side effect was also reported in children, but it wasn’t as common.

Like most other FluMist side effects, a sore throat is usually short-lived and goes away on its own. If it becomes bothersome, an over-the-counter (OTC) pain reliever or throat lozenge can provide some relief. A salt-water gargle can also help.

Similar to fever, a sore throat that doesn’t go away after a few days may be a sign of an infection. If this is the case, or if your sore throat is severe, seek medical care.

4. Headache

Headache is a common flu vaccine side effect — FluMist included. Adults are more likely to experience a headache after getting FluMist compared to children. This side effect usually starts shortly after receiving the vaccine and should go away on its own quickly.

Even if it’s mild, a headache can be unpleasant. If it’s safe for you to take, a pain medication such as acetaminophen or ibuprofen (Advil, Motrin) can help. But seek medical care if your headache is severe, lasts more than a few days, or doesn’t go away with treatment.

5. Decreased appetite

Decreased appetite is a possible FluMist side effect — especially in young children. Your body’s immune response to the vaccine can make you feel run down or more tired than usual, and a lower appetite can come along with that.

In most cases, your energy and appetite should return to usual within a few days. But if it doesn’t, or you develop other symptoms, it’s a good idea to seek medical care for evaluation.

6. Wheezing

Wheezing (trouble breathing) isn’t common after getting FluMist. But it can happen in rare cases. Wheezing can happen on its own or as part of an allergic reaction to FluMist (more on that next).

For this reason, you shouldn’t give FluMist to children ages 2 to 4 with asthma or a history of wheezing. And it should be used with caution in people ages 5 and older with asthma. Your child’s pediatrician can recommend safer flu vaccines if your child can’t receive FluMist.

If you or your child experience wheezing after receiving FluMist, seek emergency care or call 911 right away.

7. Allergic reactions

While rare, allergic reactions to FluMist are possible. Signs of an allergic reaction to FluMist may be mild, such as a skin rash or hives. But more serious reactions can cause swelling of the face and mouth, trouble breathing, and vomiting.

You may be asked to stick around for 15 to 30 minutes after receiving FluMist in case you develop an allergic reaction. The vaccination site should have medications on hand to treat you in case this happens.

It’s also possible to develop symptoms of an allergic reaction after leaving the vaccination site or if you administer FluMist at home. In this case, seek emergency care right away.

Good to know: If you’re allergic to eggs, you may have heard that flu vaccines aren’t safe for you. But that’s not the case. The FDA has determined that the egg components in flu vaccines are unlikely to cause a reaction in people with an egg allergy. So it’s fine for you to receive FluMist or other flu vaccines, unless you’ve had an allergic reaction to them in the past.

8. Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is a rare autoimmune condition that has been linked to the flu vaccine. However, the risk of developing GBS from the flu vaccine is very small. What’s more, GBS is more likely after getting the flu itself rather than after receiving the vaccine.

Symptoms of GBS can include muscle weakness, tingling, and pain. It can sometimes lead to paralysis. Long-term nerve damage from GBS is possible, but most people recover fully.

Seek medical care right away if you experience the following symptoms after receiving FluMist:

• Weakness in your arms, legs, or face

• Burning, tingling, or “pins and needles” sensations in your hands or feet

• Loss of sensation through your skin

• Muscle and/or joint pain

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Written by:

Alex Brewer, PharmD, MBA

Alex Brewer, PharmD, MBA, is a licensed pharmacist specializing in chronic disease, and health and wellness. Brewer is a medical writer and works in private practice.

Edited by:

Stacia Woodcock, PharmD

Stacia Woodcock, PharmD, is a pharmacy editor for GoodRx. She earned her Doctor of Pharmacy degree from the University of Kentucky and is licensed in New York and Massachusetts.

Reviewed by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

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