Side effects for the seasonal flu shot are mild and mostly include soreness or redness at the injection site. Sometimes hoarseness, red eyes, or itchiness occur. Side effects will appear soon after the shot is given and last one or two days.
Severe allergic reactions are very rare, but if they occur it will be a few minutes to a few hours after the shot is administered.
The flu shot does not give you the flu.
A rare side effect is a neurological disorder called Guillain-Barré Syndrome. If you have ever had Guillain-Barré Syndrome you should speak with your health care provider about getting vaccinated.