What If You React To The Flu Shot?
The flu shot uses an inactivated or “killed” vaccine. This vaccine can’t give you the flu. However, flu vaccine, like other vaccines, can occasionally cause a reaction. Feeling some response to the shot is not unusual. The vaccine acts to stimulate your immune system and prepare you to resist infection. You may feel your body's protective activity through mild symptoms. Also, some people may experience symptoms of mild sickness after getting a flu shot, but these symptoms are not necessarily connected to the shot.
If you do experience a reaction to the flu shot, it is usually local and mild—redness, soreness, and swelling at the site of the injection. Usually if you have this kind of reaction you find that it doesn't interfere with normal daily activity and does not make you feel sick. Fever and more generalized aches and pains can occur but are even less likely; those who are receiving the vaccine for the first time ever are most likely to have this type of reaction. You feel the symptoms, if any, within a few hours of the injection. The symptoms typically cause discomfort, not sickness, and last for a day or two.
Treating a Mild Reaction
To treat a mild reaction to the flu vaccine, use over-the-counter medication only for the symptoms you have (fever, swelling, nasal congestion, cough, and aches and pains). Do not give aspirin to children; use another medication to relieve their fever or aches and pains. If fever is high or symptoms persist or are severe, talk to your doctor or healthcare professional.