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'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 had at least two doses of flu vaccine (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:
Egg Allergy and the Flu Vaccine
In the past, people with an egg
allergy had to check with their doctor about whether the flu vaccine was OK for
them because it's grown inside eggs. But health experts now say that the amount of
egg protein in the vaccine is so tiny that it's safe even for kids with a severe egg
allergy. This is especially important during a severe flu season.
Still, a child with an egg allergy should get the flu vaccine 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: September 2019
