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.
Causing the Flu
Because the flu shot is a dead virus, it is not possible for it to cause the flu.
Mild Reactions
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.
Flu-Like Symptoms
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
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
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.
Tags: dead virus, immune system
