The flu shot won’t give you influenza because it contains inactive forms of the virus. However, you might have side effects like headaches, fevers, and sore muscles.

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While some people think that getting a flu shot can give you the flu, this is a common misconception.

You might experience symptoms like a fever or muscle aches after getting a flu shot, but these are just side effects.

The flu shot is generally considered very safe for most people. If you’ve had a reaction to vaccinations in the past or aren’t feeling well, it’s a good idea to speak with your doctor before getting it.

Read on to learn more about how the flu shot works and possible side effects.

The flu shot — also called the influenza vaccine — works by introducing inactive flu viruses into your bloodstream.

This triggers the immune system to create antibodies, which are proteins that protect the body from infection.

Healthcare professionals give most flu shots with an injection, but you can also get a nasal spray alternative.

The flu shot can’t give you influenza because it uses inactive viruses. However, you may experience side effects from the vaccine.

In some cases, you may catch the flu before your flu shot becomes fully effective. This doesn’t mean your vaccine didn’t work — it just means that it hadn’t had enough time to develop antibodies that protect your body from infection.

You can also develop influenza in the future even if you have the flu shot. This is particularly common if you have a weakened immune response. You can also catch a different strand of flu than the ones you have been vaccinated against.

Common side effects from the flu shot include:

  • soreness, skin color changes, or swelling at the injection sight
  • headache
  • fever
  • nausea
  • muscle aches

Side effects generally begin shortly after getting your flu shot and typically don’t last more than a few days. It’s important to mention any allergies and previous reactions with your doctor before getting a flu shot so they can discuss your options with you.

Learn more about flu shot side effects.

Getting a flu shot can help you avoid getting influenza. It can also stop you from spreading the flu to friends and loved ones.

In the 2019 to 2020 flu season, experts estimated the flu shot prevented 7 million cases of influenza.

If you do get influenza after getting a flu shot, it will likely be less severe.

Getting an influenza vaccine reduces the risk of going to the doctor with the flu by 40% to 60% and can reduce your risk of getting admitted to the intensive care unit (ICU) by 26% to 59%.

Flu vaccines can also help lower the risk of cardiac events in people with heart disease. It can also prevent worsening lung damage in people with chronic lung conditions.

Pregnant individuals who get a flu shot can offer their babies protection for several months after they’re born.

In addition to the myth that the flu shot can give you influenza, there are many misconceptions about who can get a flu shot.

One common myth is that people with egg allergies can’t get a flu shot. While you’ll want to discuss this allergy and any previous vaccine reactions with your doctor, having an egg allergy doesn’t you can’t get a flu shot.

Another group who may believe they should avoid the flu shot are pregnant individuals. Getting a flu shot is actually advisable because it can protect both you and your growing baby.

How often should I get a flu shot?

Experts recommend getting the flu shot every year for those 6 months of age or older.

Why do I feel sick after the flu shot?

Although you can’t get influenza from a flu shot, you may feel a variety of side effects like headache, fever, muscle aches, or nausea. In rare cases, you may experience an allergic reaction to an ingredient in the vaccine.

Is it safe for me to get the flu shot?

The flu shot is considered safe with very few exceptions. People who should avoid the vaccine include babies under 6 months and those with life threatening allergic reactions to ingredients in the shot.

You may wish to talk with your doctor and delay getting your flu shot if you’re feeling poorly.

A flu shot can’t give you influenza. Instead, getting a flu shot can reduce the risk of you and your loved ones becoming seriously ill from influenza. You should get a flu shot every year unless your doctor recommends otherwise.

After a flu shot, you may experience side effects like a fever, headache, and muscle pain.

If you’ve had an allergic reaction to a flu shot in the past or aren’t feeling well, it’s a good idea to talk with your doctor before getting your flu shot.

They can help advise you on alternative flu vaccinations and whether you should delay getting your shot.