What is the flu shot?
flu shot(What is a PDF document?)
is a vaccine that contains a killed form of three influenza
viruses. The vaccine causes your
immune system to make
antibodies. If you are exposed to the flu later, the
antibodies can attack and destroy the virus.
It takes about 2
weeks for your body to make the antibodies that protect you. So the best time
to get the shot is in October or November, before the flu season starts. But it
can still help if you get the shot in December or later, since flu season often
doesn't peak until February or even later. And flu is a risk year-round in the
tropics. If you are planning travel to a tropical area, you need only one flu
shot in a year.
Flu viruses change quickly, so each year
scientists make a new vaccine. To have the best chance of being protected, you
need to get a flu shot every fall.
A flu shot doesn't cost much (about $15 to $25), and most
insurance companies will pay for it.
Note: Another form of
flu vaccine is available as a spray that you breathe in through your nose. This
vaccine, called FluMist, contains live but weak viruses. Healthy people ages 2
through 49 years can usually get the nasal spray form of the vaccine (FluMist).
Pregnant women can get the flu shot but not FluMist. To find out more about
this vaccine, see the Centers for Disease Control and Prevention’s
nasal spray flu vaccine(What is a PDF document?)
Who should get the flu shot?
You should get a
yearly flu shot if you want to reduce your chance of getting the flu. Anyone
older than 6 months can get a flu shot.
It's important to get a
flu shot if you are at high risk for complications. This includes:
- People who are age
50 or older. People age 65 or older are at highest risk.
who have long-term (chronic) diseases, such as heart disease,
kidney failure, and lung disease, including
- People who live in nursing homes
or long-term care centers.
- People who have
weak immune systems.
- Children 6 months through 4 years of age. (The
flu shot is recommended for all children from 6 months to 18 years of
People who could spread the flu to people at high risk
should also get the shot. This includes:
- Anyone who lives with or cares for a child
who is 6 months or younger. (Children 6 months or younger can't get the
- Anyone in close contact with a person who is at high risk
of complications. This includes family, friends, and caregivers.
Health care workers.
Who should not get the flu shot?
should not get the flu shot without talking to their doctor first. This
- People who are allergic to
- People who had a bad reaction to the flu shot in the
- People who had a rare nerve disorder called
Guillain-Barré syndrome after a previous
- Children who are younger than 6 months of age.
People who are already sick. If you are ill and have a fever, wait until you
are better to get the shot.
People who can't get the flu shot but are at risk from
the flu may be able to take an antiviral medicine instead. For more
Should I take antiviral medicine for the flu?
What are the benefits of the flu shot?
- It may keep you from getting the flu. This
can save you time (fewer sick days) and money (fewer doctor visits, medicines,
and hospital costs).
- If you do get the flu, it can make the
symptoms milder and reduce the risk of serious complications.
can help limit the spread of the flu to others.
What are the risks of the flu shot?
It may cause
mild problems, such as soreness, redness, and swelling on the arm where you got
the shot. You might also have a fever and muscle aches for a day or two after
you get the shot.
The risk of a serious problem from the flu shot
(such as a severe allergic reaction) is very small.
in a flu shot are killed, so you cannot get the flu from a flu shot.
If you need more information, see the topic