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Everything you need to know about the flu shot


Copyright: zurijeta / 123RF Stock Photo

With the temperature cooling down, that means it's time for cold and flu season again. This year, it's more important than ever to get a flu shot. It won't protect you against Covid-19, but it can reduce your risk of getting the flu. Getting your flu shot can also keep you from having to visit a hospital, which keep nurses and doctors available to care for patients with Covid-19.

There are a couple of things you can do to avoid getting sick, like washing your hands. If you're not sure how to wash your hands the right way (and there IS a right way), we've got some great handwashing tips!

But one thing that can really help is getting your flu shot. But how exactly does the flu shot work?

What is the flu shot?

Little girl getting the flu shot
Sasi Ponchaisang/123RF

The flu shot is a vaccine that's a substance that helps to create an immunity to certain diseases and illnesses in people. Once you are immune to a disease, you can’t catch it.

The flu shot is a vaccine that helps to prevent you from getting the influenza virus, which causes the flu. This is not the same virus that causes Covid-19, which we don't have a vaccine for yet.

Vaccines are given through a shot, which is a needle that injects the vaccine into your body, usually through your arm.

How does the flu shot work?

Influenza virus particle.
You are looking at a microscopic view of the influenza virus particle, or a "viron." Photo by Cynthia Goldsmith/public domain.

The flu shot works by introducing your body to tiny little parts of different flu viruses.

This triggers a reaction from your immune system the processes in your body that fight off infection.

Your immune system realizes these virus fragments shouldn’t be in your body, and figures out how to destroy them. In the process, it learns and remembers how to fight off viruses like this in the future.

What if I get the flu virus again?

flu shots sign at a pharmacy

You can usually get your flu shot at your local pharmacy. (Photo by Mike Mozart licensed CC BY 2.0)

Don't worry. If you’re exposed to that kind of virus again, your body already knows how to take care of it. It can destroy the virus before you actually get sick.

This is how vaccines work. They give your body a virus or bacteria that is either dead or otherwise deactivated.

That way, the virus or bacteria can’t actually get you sick, but your body can still recognize it and learn how to fight it. 

Can I still get sick after getting the flu shot?

Girl blows nose.

It's possible. Every year, scientists develop a new flu shot. This is because the flu virus is constantly mutating — that means it changes all the time.

That makes it impossible to know which strains are going to spread the most during any given flu season.

Scientists make a vaccine using strains that they think are most likely to get people sick. But sometimes a strain they didn’t consider spreads more and people still get sick.

I hear the flu shot doesn't work

girl who is sick with teddy bear

It's complicated. The influenza virus isn’t the only virus that creates similar symptoms.

You might get a flu shot and still get a common cold, which can feel a lot like the flu. Because of this, some people think the flu shot didn’t work, even though it did.

It’s important to remember that no medicine is 100% effective, 100% of the time. That said, you’re much less likely to get the flu if you get the flu shot. 

Are there any side effects?

runny nose

Photo credit: jspad via Visual Hunt / CC BY-NC-SA

Just like with any medicine you take, the flu shot does have some potential side effects.

Most of them are fairly minor like soreness around where you got the needle and some flu-like symptoms (yep, you can get flu symptoms from the flu shot).

Although it might sound crazy, feeling a little flush actually means the vaccine is working! Those light symptoms are just your body figuring out how to deal with the virus.

More serious side effects can include allergic reactions, but they are really rare. That said, if you experience an allergic reaction, call a doctor immediately.