Flu Information

Influenza, more commonly known as "the flu", is a highly contagious disease that can cause fever, cough, sore throat, headache, muscle aches, and fatigue. Complications of the infection include pneumonia, seizures (in children), and worsening of existing conditions such as heart disease, asthma, and diabetes. Every year in the United States, up to 20 percent of the population gets the flu, and more than 200,000 hospitalizations and about 36,000 deaths occur from flu complications. Approximately 90 percent of these deaths are among people age 65 and older. Although the incidents of influenza are the highest in young children and they serve as a main source of flu virus transmission, deaths among children are uncommon. The flu is caused by influenza viruses, and is spread from person to person through coughing and sneezing.

Flu Vaccine Information

Because influenza viruses are constantly changing, an annual flu vaccination is recommended as protection against the flu. The flu vaccine is commonly available in August and September, and throughout the flu season, which runs from August to May. It's usually takes about two weeks for the vaccine to work, and its protection will last throughout the flu season.

This vaccine is given as an injection into the arm or thigh muscle, which is known as an intramuscular (IM) injection. The vaccine contains an inactive, or killed, virus so it is not possible for someone to get the flu from the vaccine.

There is also a nasal spray version of the flu vaccine available.

Who Should Receive the Flu Vaccine?

  • Everyone over the age of 6 months

Flu Vaccination Schedule

  • A single dose is recommended for most people
  • Children younger than 9 years of age receiving influenza vaccine for the first time
    • - Two doses separated by at least 4 weeks

Influenza vaccine may be given at the same time as other vaccines.

Side Effects

Mild-to-Moderate Problems

  • Soreness, redness, or swelling where the shot was given
  • Fever and aches

Severe Problems (Rare)

  • Serious allergic reactions, with symptoms including:
    • - Difficulty breathing
    • - Wheezing
    • - Hives
    • - Pale skin
    • - Fast heartbeat
    • - Dizziness

Over-the-counter pain relievers such as acetaminophen or ibuprofen can help ease pain and reduce fever.

It is extremely rare for this vaccine to cause serious harm or death. If the person getting the vaccine has a serious reaction, call the doctor or seek immediate medical attention.

Who Should Not Receive the Flu Vaccine?

  • Those with moderate or severe illness (for example, a severe cold, flu or infection of the sinuses or lungs) should not receive the vaccine until symptoms of the illness improve.
  • People with history of Guillain-Barre syndrome, a severe paralytic illness, also called GBS, should talk to their doctor before getting the vaccine.
  • Persons with hypersensitivity or an allergy to eggs should not receive the vaccine, as it is grown in eggs.
  • Those who previously had a severe, life-threatening allergic reaction to the vaccine or any ingredient in the vaccine should not be vaccinated.

Additional Information

Tell your doctor or a healthcare provider if the person getting the vaccine has any severe allergies.

Call the Centers for Disease Control and Prevention (CDC) at 800-232-4636 or visit the CDC website, at  cdc.gov/vaccines, for more vaccine information.

This publication should be used for general educational purposes only and is not intended to be a substitute for professional medical advice. Be sure to contact your doctor, pharmacist, or other healthcare provider for more information about human papillomavirus. Although it is intended to be accurate, neither Walgreen Co., its subsidiaries or affiliates, nor any other party assumes liability for loss or damage due to reliance on this publication.


Atkinson W, Hamborsky J, McIntyre L, Wolfe S, eds. Centers for Disease Control and Prevention (CDC).Epidemiology and Prevention of Vaccine-Preventable Diseases. 10th ed. Washington, DC: Public Health Foundation, 2007.

Vaccine Information Statement: inactivated influenza vaccine. July 16, 2007.cdc.gov/vaccines/pubs/vis/default.htm. Accessed April 2008.

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