The thing with Flu shots are that it only protects you from the basic Flu Virus...it does not prevent any new Flu Viruses from getting in your system. Also, the different Flu Viruses continue to evolve making it harder for the basic Flu shot to work, thus you will always have to take the Flu shot every year and it still does not fully protect you. And as with anything you inject in your body, there will always be some risk!