A pediatrician sits with a young patient.

The nasal spray flu vaccine, FluMist Quadrivalent, is back on the Center for Disease Control and Prevention’s list of options for flu protection for the first time since the 2015 to 2016 flu season. But it probably shouldn’t be the first choice for your children this year—at least according to new guidance from the American Academy of Pediatrics (AAP).

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The CDC recommended not using the nasal spray for the last two flu seasons because it appeared to be less effective than the flu shot in children—the population it had mostly been used in previously. (It’s approved for people between ages 2 and 49, with the exception of children with underlying medical conditions, pregnant women, people with weakened immune systems, and several other groups.)

More recently, the nasal spray’s manufacturer presented data suggesting that a new formulation may protect against the flu just as well as the shot, the CDC says.

But while evidence from lab tests is promising, there’s no real-world proof of that yet, according to the pediatrics group.

“We just don’t know what the vaccine effectiveness will be during the upcoming flu season, especially against the influenza A, H1N1, strain,” says Hank Bernstein, D.O., a member of the CDC’s Advisory Committee on Immunization Practices (ACIP) and an ex officio member of the AAP Committee on Infectious Diseases.

That’s why the AAP recommends the flu shot as the first choice for children and says you should consider the nasal spray flu vaccine only as a backup, such as for children who are especially fearful of needles. The CDC doesn’t recommend one form of the vaccine over another for children or adults.

AstraZeneca, which makes the nasal spray, says in an emailed statement that it “believes that FluMist Quadrivalent continues to provide an important option for flu vaccination in the U.S. and we respect the role of the CDC, ACIP, and AAP in protecting and advancing public health. We encourage patients to speak with their healthcare providers to determine the influenza vaccination option that’s right for them or their families.”

Here is more about the nasal spray flu vaccine and the flu shot.

The Nasal Spray Vaccine, Explained

The nasal spray, which first became available in 2003, uses weakened or attenuated live flu viruses. These live viruses can’t infect you, but they can “teach” the immune system to recognize and fight the flu virus, in case you come across it. (The flu shot works similarly but doesn’t use live viruses.)

“The nasal spray vaccine worked wonderfully for a number of years,” Bernstein says.

It was even recommended as the preferred method of vaccination for children ages 2 through 8 during the 2014 to 2015 flu season because evidence suggested that it might be even more effective than the flu shot for them. At that time, for adults, it appeared to work about as well as the flu shot, says William Schaffner, M.D., professor of preventive medicine and infectious diseases at the Vanderbilt University School of Medicine in Nashville and a member of ACIP’s influenza vaccine work group.

However, later research revealed that the nasal spray wasn’t as effective in children as initially thought. “In recent years—between 2013 and 2016—the live attenuated influenza virus did not perform as well as the flu shot,” Bernstein says.

In particular, the nasal spray appeared less effective than the shot against H1N1—the strain of influenza type A that caused the 2009 to 2010 influenza pandemic (but not last year’s severe flu).

For this upcoming flu season, the manufacturer developed a new formula for the part of the nasal spray vaccine that targets H1N1. And the CDC decided that evidence—from lab tests—was robust enough to add the vaccine to its list of recommended options again this year. 

What Should You Do?

How much will the choice of shot or nasal spray matter for the upcoming flu season? While Schaffner says that the nasal spray’s protection against H1N1 is still uncertain, the CDC notes that evidence indicates that the spray will provide a similar level of protection as the shot against influenza B and the H3N2 strain of influenza A—the strain that wreaked havoc last year.

Of course, we don’t yet know what flu strains are most likely to circulate this year. (All flu vaccinations provide protection against either three or four strains of flu. The nasal spray protects against four.)

The AAP’s recommendation that the flu shot should be the primary vaccine choice is meant to apply solely to children. But if your children—or you—are likely to avoid flu vaccination altogether because of a fear of needles, opt for the nasal spray, experts say.

The most important thing to remember is that everyone 6 months and older should receive a flu vaccination in an appropriate form, according to public health officials. Last year’s flu caused a record number of deaths in children, according to the CDC, and most kids who die from flu are unvaccinated.

It’s advisable to get vaccinated by the end of October, before the flu begins to circulate widely (though it’s not too late to get the vaccine later in the season). 

Finally, keep in mind that whichever vaccine you choose, children between 6 months and 8 years old who have never had the flu vaccine before—or who have only had one dose of it in a previous season—will need two doses of the flu shot (or nasal spray) this season, spaced four weeks apart.