I would not consider risking a flu shot.
I have had bad reactions to shots in the past and I don't want to go through that again.
I am eating 8 shiitake mushrooms/day to boost immunity, and taking a few doses of anti-vral herbs as a prophylactic measure.
I've also found it important to:
1) bring my mask when I'm out in public, and put it on if I hear someone sneeze or cough
2) wash my hands after any trips out into the world
3) wash my hands after any contact with money and the mail
4) request everyone who comes into my house wash their hands
5) not eat any raw food until flu season is over.
That's the best I can do for prevention.