Does the Flu Shot Cause Flu Symptoms?
The flu shot contains a dead flu virus and signals the immune system to produce antibodies that kill off the flu virus when it enters the body. A new flu shot is produced each year as flu virus stains change.
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Causing the Flu
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Because the flu shot is a dead virus, it is not possible for it to cause the flu.
Mild Reactions
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While most people tolerate the flu shot well, some may have mild reactions such as soreness and swelling at the injection site, low-grade fever and a general unwell feeling.
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Flu-Like Symptoms
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People may have flu-like symptoms right before or after receiving the flu shot, become ill from a non-flu virus, exposure to a flu virus not contained in the flu shot or if they have a weakened immune system.
Allergic Reactions
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Allergic reactions to the flu shot are rare, but can be life-threatening. Seek medical attention if this occurs.
Who Should Avoid the Flu Shot
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People with an allergy to eggs, hypersensitivity to prior flu shots, recent fever, or have developed Guillain-Barré syndrome after a previous flu shot should avoid the shot.
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