What Is the FluMist Flu Vaccine?

FluMist Quadrivalent is a nasal spray flu vaccine that can be used as an alternative to the flu shot in some people. Studies suggest that the two options offer a similar level of protection from flu.

FluMist may be a good option for adults or adolescents who are averse to injections or when there is a shortage of the traditional flu vaccine.

As opposed to injectable flu vaccines, which are made with inactivated (killed) viruses, FluMist is a live attenuated vaccine made with weakened live viruses. Because of this, it must not be used by people with compromised immune systems.

Uses for FluMist

FluMist Quadrivalent is approved by the U.S. Food and Drug Administration (FDA) for use in healthy, non-pregnant people between the ages of 2 and 49.

Quadrivalent refers to the fact that it is designed to protect against four different flu viruses: two influenza A viruses and two influenza B viruses. The specific variants chosen for each annual flu vaccine are based on surveillance from over 100 national influenza centers in over 100 countries.

FluMist was first approved for use in 2003. However, it was found to be less effective than flu shots in children during the 2012-2013 and 2013-2014 flu seasons, leading the Centers for Disease Control and Prevention (CDC) to temporarily drop its recommendation for the 2016-2017 and 2017-2018 seasons.

Before Taking

FluMist is an effective vaccine choice for some, but not all.

The vaccine is contraindicated for use in people who have had a prior severe allergic reaction to FluMist or any of the components of the vaccine, including egg protein.

FluMist should also not be given to the following groups:

• Children under 2 years
• Adults 50 and older
• Children 2 to 4 years who have asthma or experienced wheezing within the past 12 months
• Children 2 to 17 years who are taking aspirin or any salicylate-containing medication
• People with weakened immune systems
• People without a spleen or who have a non-functioning spleen
• Pregnant women
• People with an active cerebrospinal fluid leak into the mouth, nose, or ear, or from other places in the skull
• People with cochlear implants

People who have recently taken flu antiviral drugs may need to delay vaccination for two to five days.

FluMist should be used with caution in:

• People with asthma over 5 years of age
• People with chronic health conditions, such as heart disease, kidney disease, lung disease, and diabetes
• People who have had Guillain-Barré syndrome within six months of a previous dose of a flu vaccine

Other Flu Vaccines

FluMist is the only live attenuated flu vaccine, as well as the only nasal spray flu vaccine.

There are other quadrivalent flu vaccines delivered by injection and available under the brand names:

• Afluria Quadrivalent
• Fluarix Quadrivalent
• Flublok Quadrivalent*
• Flucelvax Quadrivalent*
• FluLaval Quadrivalent
• Fluzone Quadrivalent

^{*Not derived from chicken eggs and considered safe for use in people with egg allergy.}

If FluMist is not recommended, speak to your healthcare provider about which of these is.

Dosage

FluMist is a fine, dry powder delivered in a syringe-like sprayer. Each sprayer contains 0.2 milliliters (mL) of the vaccine, enough for a 0.1-mL dose in each nostril.

The recommended dosage varies by age and flu vaccination history, and may include one or two doses of the vaccine.

How to Administer

FluMist is administered by a healthcare professional. One spray is given into each nostril with a brisk compression of the suppressor.

You can breathe normally during the administration and do not have to sniff.

Side Effects

Side effects are common with all drugs and vaccines, and FluMist is no exception. Most are mild and transient and will usually resolve within a day. On very rare occasions, severe side effects may occur.

Common

According to pre-market clinical trials, FluMist was reported to cause the following side effects in 4% or more of users:

• Runny nose
• Nasal congestion
• Headache
• Lethargy/tiredness
• Decrease appetite
• Muscle aches
• Fever (usually mild)

Most side effects were low-grade and resolved on their own without treatment.

Severe

Younger children are at an increased risk of wheezing after receiving FluMist. Although the majority of cases in premarket studies involved children under 2 years old, the risk of wheezing remained elevated up until age 5. Some cases required hospitalization.

Allergic reactions to FluMist, while possible, are extremely rare. Those who may experience a reaction (including a severe whole-body allergy known as anaphylaxis) are people with a severe egg allergy.

Even so, vaccine-induced anaphylaxis is rare. In the United States, only 33 cases of anaphylaxis were reported out of over 25 million doses of childhood vaccines delivered from 2009 to 2011, according to a 2016 review of the Journal of Allergy and Clinical Immunology.

Warnings and Interactions

FluMist is avoided in children up to the age of 17 who take aspirin. There is concern that FluMist may trigger a potentially severe condition called Reye's syndrome in children recovering from viral infections.

Aspirin should be avoided for four weeks following vaccination with FluMist in anyone under the age of 18.

FluMist should also not be taken with antiviral drugs used to treat flu symptoms. There are four such drugs currently approved by the FDA:

• Rapivab (peramivir)
• Relenza (zanamivir)
• Tamiflu (oseltamivir phosphate)
• Xofluza (baloxavir marboxil)