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Influenza Vaccine


The influenza vaccine

is an injection given to help prevent influenza (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 flu shot usually injected into your upper arm. It may be given in your thigh. You may get a vaccine with a weak or dead virus.

Call 911 for any of the following:

  • 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.

Seek care immediately if:

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

Contact your healthcare provider if:

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

When to get the influenza vaccine:

The influenza vaccine is offered every year starting in early fall. Get the influenza vaccine as soon as it is available. Children 6 months through 8 years old need 2 doses during the first year they get the vaccine. The 2 doses should be given at least 4 weeks apart. It is best if the same type of vaccine is given both times. The child can then receive 1 dose each year. Children 9 years or older should get 1 dose each year.

Immunization Schedule

Who should get the flu shot:

  • Infants 6 months or older
  • Any healthy adult who would like to decrease the risk for the flu
  • Anyone living with or caring for children younger than 5 years
  • Healthcare workers
  • Anyone who lives in a long-term care facility
  • Anyone who has chronic health problems, such as asthma, diabetes, or blood disorders
  • Anyone who has a weak immune system
  • Women who are or will be pregnant during the flu season

Who should not get the flu shot:

If you have an egg allergy, ask your healthcare provider if it is safe to get the flu shot. You will need to be closely monitored by a healthcare provider while you receive the vaccine, and for an hour or more after. The following should not get the flu shot:

  • Infants younger than 6 months
  • Anyone who has had an allergic reaction to the flu shot
  • Anyone who is sick or has a fever
  • Anyone who received a diagnosis of Guillain-BarrĂ© syndrome within 6 weeks of getting a flu vaccine
  • Anyone who is allergic to thimerosal (mercury)

Risks of the influenza vaccine:

The flu shot may cause mild symptoms, such as a fever, headache, and muscle aches. It may also cause mild to moderate soreness or redness at the area where you were given the shot. The nasal spray may cause a fever, runny or stuffy nose, headache, muscle aches, or vomiting. You may still get the flu after you receive the influenza vaccine. If you are allergic to eggs, ask about an egg-free vaccine. You may have an allergic reaction to the vaccine. This can be life-threatening.

Follow up with your healthcare provider as directed:

Write down your questions so you remember to ask them during your visits.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Learn more about Influenza Vaccine (Ambulatory Care)

Associated drugs

Micromedex® Care Notes