This means you can't get the flu from the shot. Your immune system needs six to eight weeks to respond to the vaccination, so getting a flu shot after your child comes down with the flu is not going to help you. Because the vaccine is only effective for about a year, and because it targets different flu strains every year, you must be vaccinated every year. Who Needs Immunization Consult your physician about your need to be immunized. Most people feel perfectly fine after getting a flu shot.
Some people have mild flu-like symptoms such as fever and sore muscles for a few days.
This is not the flu. You cannot get the flu from the vaccination because it contains only inactivated viruses. If you develop an upper respiratory illness after you get the flu shot, it means you were exposed to a different kind of bug, and has no relation to the vaccination. Some people should avoid flu shots. Colds are caused more than two hundred different viruses.