What type of symptoms should you be worried about after getting a flu shot?

Answer 1

Flu vaccinations have been proven safe and effective over decades of use. There are very few severe reactions from these important disease preventing inoculations. The most common would be allergic responses. If you have never had a flu vaccination before, you should be aware of any new symptoms that come on suddenly such as difficulty breathing, a feeling that your throat is swelling shut, or other systemic allergic responses like rash, hives, etc. If this is going to happen, it will usually happen soon after the injection, so you could tell the clinician who gives the injection that it is your first time and they may suggest that you stay for 20 - 30 minutes at that location after the shot to watch for adverse reactions. It is rare, however.

Minor symptoms, not to worry about but that are uncomfortable temporarily, are at the local injection site such as muscle soreness from the injection, mild swelling and redness with some heat and even some mild flu-like symptoms such as low grade fever, mild fatigue and general malaise.

All of the local reactions should be gone in 2 or 3 days. If the area becomes more red and swollen as time goes by instead of less, there is the ever so slight chance that the injection introduced bacteria to the site, and you may need to have it examined to be sure there is no bacterial infection.

If you know you are allergic to eggs or chicken, you used to not be able to get a flu vaccination since the virus for the vaccine is grown in chicken eggs at the drug manufacturer. Now, however, you may be able to get the vaccine even with those Allergies. See the related question below for more about that.