Flu shots are completely unnecessary and a way to use people's fears to make big money for the Pharmaceuticals. The flu shot does not guarantee immunity from the flu - at best it is guess work, which means you are injecting your body with something that has a high likelihood of not working. Every year the strains mutate and if the vaccines get it wrong, well then you just pumped your body full of something else for it to fight that won't work anyway. In fact, you just taxed your immune system by having the shot - so now the body has more things to fend off - not less.
Instead, I would suggest taking natural steps to boost your immunity and take precautions. Should you actually contract the flu a dose of the anti-viral Tamiflu is very effective for getting rid of the virus. My son contracted the much feared "swine flu" a couple of years ago. We immediately called the doctor who gave him a scrip for Tamiflu and he was better in less than 24 hours. Tamiflu is an anti-viral and IS effective.
I never contract the flu anyway - I've had it once that I can remember and I have never taken a flu shot. I also work to boost my immunity through the season with a healthy diet and supplements and if I feel sick I do society a favor and stay home.