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Your Child's Immunizations: Influenza Vaccine


What Is the Flu?

Influenza — what most of us call "the flu" — is a contagious viral infection of the nose, throat, and lungs. It can make a person feel very sick.

When Should People Get the Flu Vaccine?

Flu season runs from October to May. It's best to get a flu vaccine as early in the season as possible, ideally by the end of October. This gives the body a chance to make antibodies that protect from the flu. But getting a flu vaccine later in the season is better than not getting it at all.

Who Should Get the Flu Vaccine?

The Centers for Disease Control and Prevention (CDC) recommends a flu vaccine for everyone 6 months of age and older.

But it's especially important that those in higher-risk groups get vaccinated to avoid health problems from the flu. They include:

  • all kids 6 months through 4 years old
  • anyone 65 years and older
  • all women who are pregnant, are trying to become pregnant, have recently given birth, or are breastfeeding during flu season
  • anyone whose immune system is weakened from medications or illnesses (like HIV infection)
  • people who live in long-term care facilities, such as nursing homes
  • any adult or child with chronic medical conditions, such as asthma or diabetes
  • kids or teens who take aspirin regularly and are at risk for developing Reye syndrome if they get the flu
  • caregivers or household members of anyone in a high-risk group (like children younger than 5 years old, especially those younger than 6 months, and those with high-risk conditions)
  • Native Americans and Alaska Natives

Babies younger than 6 months can't get the vaccine, but if their parents, other caregivers, and older kids in the household get it, that will help protect the baby. This is important because infants are more at risk for serious problems from the flu.

How Is the Flu Vaccine Given?

  • Kids younger than 9 years old will get two doses of flu vaccine, spaced at least 1 month apart, if they have've had fewer than two doses before July 2019. This includes kids who are getting the flu vaccine for the first time.
  • Those younger than 9 who have received at least two doses of flu vaccine previously (in the same or different seasons) will only need one dose.
  • Kids older than 9 need only one dose of the vaccine.

Talk to your doctor about how many doses your child needs.

What Are the Types of Flu Vaccines?

Two types of flu vaccine are available for the 2019–2020 flu season. Both protect against four types of influenza virus:

  • the flu shot, which is injected with a needle
  • the nasal spray, a mist which gets sprayed into the nostrils

In the past, the nasal spray vaccine wasn't recommended for kids because it didn't seem to work well enough. The newer version appears to work as well as the shot. So either vaccine can be given this year, depending on the child's age and general health.

The nasal spray is only for healthy people ages 2–49. People with weak immune systems or some health conditions (such as asthma) and pregnant women should not get the nasal spray vaccine.

Why Is the Flu Vaccine Recommended?

While the flu vaccine isn't 100% effective, it still greatly reduces a person's chances of catching the flu, which can be very serious. It also can make symptoms less severe if someone does still get the flu after immunization.

Even if you or your kids got the flu vaccine last year, that won't protect you this year, because flu viruses change. That's why the vaccine is updated each year to include the most current types of the virus.

Sometimes the same types are included in the vaccine one year after the next. Even then, it's still important to get the yearly flu vaccine because the body's immunity against the influenza virus declines over time.

What Are the Possible Side Effects of the Flu Vaccine?

Usually given as an injection in the upper arm, the flu shot contains killed flu viruses that will not cause someone to get the flu. But it can cause mild side effects like:

  • soreness, redness, or swelling at the injection site
  • a low-grade fever
  • aches

The nasal spray flu vaccine contains weakened live flu viruses, so it may cause mild flu-like symptoms, including runny nose, headache, vomiting, muscle aches, and fever. 

Very rarely, the flu vaccine can cause a severe allergic reaction.

What Happens After Flu Immunization?

If your child has any side effects, talk to your doctor about giving either acetaminophen or ibuprofen and to find out the right dose.

A warm, damp cloth or a heating pad on the injection site may help reduce soreness, as can moving or using the arm.

What Else Should I Know?

Some things might prevent a person from getting the flu vaccine. Talk to your doctor to see if the vaccine is still recommended if your child:

In the past, the nasal spray vaccine wasn't recommended for kids because it didn't seem to work well enough. The newer version appears to work as well as the shot. So either vaccine can be given this year, depending on the child's age and general health.

Still, a child with an egg allergy should get the flu shot in a doctor's office, not at a supermarket, drugstore, or other venue.

If your child is sick and has a fever, or is wheezing, talk to your doctor about whether to reschedule the flu vaccine.

When Should I Call the Doctor?

Call if:

  • you aren't sure if the vaccine should be postponed or avoided
  • there are problems after the immunization, such as an allergic reaction or high fever, or if you have other concerns
Date reviewed: October 2018