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The Flu Vaccine

If you've ever had the flu, you know how bad it can make you feel. To help avoid all that misery — as well as possible health complications — doctors now recommend that all teens get a flu vaccine every year.

Why Get the Flu Vaccine?

The main reason for getting vaccinated is to spare yourself the misery of flu. But there are other reasons to get vaccinated too.

It's especially important for people with some medical conditions (like kidney disease, diabetes, HIV, heart problems, or asthma) to get a flu vaccine. They are more likely to have serious complications (like pneumonia) when they get the flu.

Kids and teens who take aspirin regularly also need to be vaccinated. They are at risk for developing a serious condition called if they get the flu.

Another reason for getting vaccinated is to protect the people around you who might get seriously ill from flu — like babies, people with serious illnesses, and the elderly. When you protect yourself with a flu vaccine, you also protect other people who are more vulnerable because there's less chance you'll get the flu and pass it on. (Sometimes people call this "herd immunity.")

When Should a Person Get Vaccinated?

The best time to get a flu vaccine in the United States is before flu season starts. This gives the body a chance to build up immunity before the winter flu season. It's best to get vaccinated as soon as this year's flu vaccine becomes available, which usually is around September. (Your mom or dad can find out when that is from your doctor's office, or you can ask your school nurse.)

Even if you can't get vaccinated right away, getting a flu vaccine after flu season begins will still give you some protection. You also can protect yourself against the flu (and many other infections) by washing your hands well and often.

What's in a Flu Vaccine?

Flu vaccines come in two forms, a shot and a nasal spray. The shot contains killed flu viruses that won't make someone get the flu, but will cause the body to make antibodies to fight off infection by the live flu virus. This is the preferred form of flu vaccination because it has been shown to be both safe and effective.

The nasal spray (FluMist®), which contains weakened live flu viruses, was not used in recent flu seasons because it didn't work as well as the shot. A new version of it is now recommended for the 2018–2019 flu season as an option for people who otherwise might not get a flu shot (for example, if your doctor's office has run out of the shot).

The flu vaccine is very effective at protecting against the flu, but it's not 100%. In addition, the shot only contains some strains of the virus. If a new flu strain emerges, a person who's had a shot may not be protected against it. A few people who get vaccinated might get the flu, but it will be much milder and resolve more quickly than if they had not been vaccinated.

Does the Flu Vaccine Have Side Effects?

It's possible to have some minor side effects for 1 or 2 days after getting a flu shot, like soreness in the area where you got the shot. Some people may feel achy or have a mild fever after getting the shot. And the nasal spray vaccine might cause mild flu-like symptoms. But the side effects aren't as bad as the flu, which can make some people sick for as long as 2 or 3 weeks.

If you have an egg allergy, get your flu shot in a doctor's office, not at a supermarket, drugstore, or other venue.

Date reviewed: March 2019