For most people getting the flu vaccine does really help prevent the flu virus from infecting you.
But some people do still get the flu when they have had the flu vaccine which is normal but when you do have the flu vaccine the flu virus is usually less severe and lasts less time in your body than it would without the flu vaccine.
Some years when I have the flu vaccine I never get the flu after having the flu vaccine but sometimes I do still get the flu but the good thing about the flu vaccine is that I don't feel as awful and I recover from the flu much faster.
You must get the flu vaccine before the flu season starts or at least before the flu has time to infect you or it will not work.
Your health insurance will usually pay for a flu vaccine but if not the cost of a flu vaccine is not all that expensive.
You can usually get a flu vaccine for less than $100.00 depending on where you have the flu vaccine.
Also be aware that your arm may hurt for awhile after having the flu vaccine which is normal as well and usually the pain from the flu vaccine goes away within a day or so.