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What Is the Flu?

Influenza (say: in-floo-EN-zah) is also called the flu. It's an infection that causes a fever, chills, cough, body aches, headaches, and sometimes earaches or sinus problems.

The flu is caused by the influenza virus (say: VY-rus). A virus is a microorganism (say: my-kroh-OR-guh-niz-uhm), which means it's so small that you can't see it without a strong microscope.

flu virus illustration

Kids Older Than 9 Need One Shot

The flu vaccine is available as a shot (injected through the skin) or as a spray mist (into the nostrils). Most kids older than 2 can get the spray mist.

The Centers for Disease Control and Prevention (CDC) recommends the flu vaccine for all people age 6 months and older. If you're a kid, that means you!

Kids older than 9 need only one dose.

If you are younger than 9, you will need one or two flu shots. It depends on whether you had the flu shot before and when you received those vaccinations. If you are younger than 9, you will need only one shot if you have had two doses of flu vaccine since July 2010. (Your parents and doctor can look this up and figure out if you did or not.)

If you are younger than 9, you will get two flu shots if:

  • you are getting the flu vaccine for the first time
  • you have had the flu shot before, but you have not had two doses of the flu vaccine since July 2010

If you need two shots, you'll get one shot and then come back at least a month later to get the second one.

Certain people are at higher risk of complications from the flu, including:

  • pregnant women
  • kids younger than age 5
  • people age 65 and older
  • people of any age who have long-term health conditions

So if you're a kid who has asthma, diabetes, or another health problem, it's especially important that you get the flu vaccine.

Flu vaccines are usually given in the fall, before flu season starts. Flu season — the months of the year when a lot of people have the flu and it's easy to catch it — usually starts in October and ends in May.

Why Get a Shot?

If you get the flu vaccine, by nose spray or shot, it will protect you from getting a bad case of the flu. You either won't get the flu at all or, if you do get it, you will have only mild symptoms and you should get better pretty quickly.

You might wonder why you have to get a flu shot every year. Here's why: There are lots of different flu viruses. Each year, researchers choose the three viruses most likely to cause trouble. The flu vaccine includes protection against those three, which vary from year to year.

How Does the Flu Spread?

This virus gets around in little drops that spray out of an infected person's mouth and nose when he or she sneezes, coughs, or even laughs. You can catch the flu from someone who has it if you breathe in some of those tiny flu-infected drops.

You can also catch the flu if those drops get on your hands and you touch your mouth or nose. No wonder people are always saying to cough or sneeze into your elbow. And while you're at it, wash your hands!

cough illustration

What If You Get the Flu?

If your doctor thinks you might have the flu, sometimes he or she will use a long cotton swab to get a sample of the gunk in your nose. Testing this sample in a lab can determine if you have the flu.

But usually this isn't necessary. Based on your symptoms and how you look during the visit, your doctor can usually tell if you have the flu, especially during times when a lot of flu is going around your town.

Once your doctor says you have the flu, start taking these steps to feel better:

  • Rest in bed or on the couch.
  • Drink lots of liquids, like water, chicken broth, and other fluids.
  • Take the medicine your mom or dad gives you to ease your fever, aches, and pains.
  • Tell your mom or dad if you have trouble breathing, if you are feeling worse instead of better, or if you aren't peeing as much as usual. These are signs you may need to see the doctor again.

Most of the time, you'll feel better in about a week. Until then, you'll have to stay home from school and take it easy.

We hope you're flu-free this year, but if you do get the flu, now you know what to do!

Reviewed by: Elana Pearl Ben-Joseph, MD
Date reviewed: September 2013

Other Related KidsHealth Articles:
A Kid's Guide to Fever
What are fevers? Why do kids get them? Get the facts on temperatures and fevers in this article for kids.
A Kid's Guide to Shots
If you're old enough to read this, you've probably had most of your shots. But even bigger kids may need a shot once in a while. Find out more about them in this article for kids.
Flu Center
The flu can make you sick for a week or more. Find out how to get protected from the influenza virus.
The Flu: Should You Go to School?
Stay home or go to school? That's what you are probably wondering if you have the flu. Find out more.
The Flu: Stop the Spread
Follow these tips to help prevent the spread of the flu.
What to Do if You Get the Flu
If you have the flu, you'll want to do all you can to feel better. Find out more in this article for kids.
Who Needs a Flu Shot?
Just about everybody needs a flu shot. Find out more in this article for kids.
Related Resources:
American Lung Association
The mission of this group is to prevent lung disease and promote lung health. Contact the group at: American Lung Association 61 Broadway, 6th Floor NY, NY 10006 (212) 315-8700
CDC: Flu (Influenza)
The CDC's site has up-to-date information on flu outbreaks, immunizations, symptoms, prevention, and more.