Typically you should check if you belong to one of the risk groups.
If you are a normal, healthy person, chances are that the flu itself is not very dangerous for you. For infants, old people or people with weakened immune system, this might look different.
When my wife was undergoing chemotherapy, and had a weakened immune system, it was logical for me to get the flu shot for myself and our kids, simply to reduce the risk of any of us picking up the flu and infecting her (although the flu shot is not vegan most of the time).
Best regards,
Andy