The "Flu Shot" doesn't protect you from getting "the flu". It protects you against one deadly strain of influenza. That's it. ONE STRAIN.
If you're exposed to that particular strain and your body can't fight it, you're likely dead. It's particularly deadly for children under five and people over 60 years old.
If you take the shot and you become sick, it's not the vaccine that makes you sick, it's carrier that they wrap the vaccine in. It won't last more than 24 hours and is an allergic reaction.
It's available in spray form and doesn't contain the eggs, etc. that are necessary for the shot.