Eat well and exercise. Your immune system should be the one fighting stuff off.
I know countless people who now REJECT these “flu shots”. They've been sick as dogs too. More often than not the “strain” you are injected with is NOT the “strain” that is the hottest “flu”. It's just a money maker for the pharms that team up with government. And of course, who can resist a “crisis” in the Obama administration?
Actually, the drug companies have tried to get OUT of the fluvax business, but the gummint won’t let them. Tain’t a money-maker...