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Flu Shot (Vaccine) for Adults


What is the flu shot?

The flu shot is a vaccine given in your upper arm or thigh to help prevent influenza (the flu). The flu is caused by a virus. The virus spreads from person to person through coughing and sneezing. Several types of viruses cause the flu. The viruses change over time, so new vaccines are made each year. The vaccine begins to protect you about 2 weeks after you get it. The vaccine is offered every year starting in early fall. Get the vaccine as soon as recommended each year, usually in September or October.

Who should not get the flu shot or should wait to get it?

You may need to wait to get the flu shot, or instead get the nasal spray. Tell your healthcare provider if:

  • You had an allergic reaction to a flu shot, or you have any serious allergies.
  • You are sick or have a fever of 101°F (38.3°C) or higher.
  • You developed Guillain-Barré syndrome within 6 weeks of getting a flu shot.

What do I need to know about the flu vaccine and egg allergies?

The flu vaccine may contain a small amount of egg protein. The amount is so low that it is not likely to cause an allergic reaction. Tell your healthcare provider if you have an egg allergy before you get the flu vaccine. Egg-free vaccines may be available, but do not delay getting a flu vaccine to wait for it.

What are the risks of the flu shot?

The vaccine may cause mild symptoms, such as a fever, headache, and muscle aches. You may also have mild to moderate soreness or redness at the area where you were given the shot. You may still get the flu after you receive the vaccine. You may have an allergic reaction to the vaccine. This can be life-threatening.

Call your local emergency number (911 in the US) if:

  • Your mouth and throat are swollen.
  • You are wheezing or have trouble breathing.
  • You have chest pain or your heart is beating faster than normal for you.
  • You feel like you are going to faint.

When should I seek immediate care?

  • Your face is red or swollen.
  • You have hives that spread over your body.
  • You feel weak or dizzy.

When should I call my doctor?

  • You have increased pain, redness, or swelling around the area where the shot was given.
  • You have questions or concerns about the flu shot.

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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