a vaccine just puts a little of the flu viruses into your system (dead virus), and your body will do the
rest by building resistance, just as though you had the flu and recovered, which also leaves resistant
anti bodies in your system, quite a natural process
its not like an anti biotic, which attacks the disease itself, then the disease will mutate to be
stronger the next time against that disease, 'unless' the disease is totally killed off, which is why
one must take the complete prescription and not 'stop' before medicine is gone.
anyway, that is the way I understand the process.
i've never had any side effects from the flu shot, after years and years of receiving it, and i've
also not had the flu in all those years, I know they don't know 'exactly' what flus wil arrive each
year, but the studies they do each 'off' season to decide just what to use are very accurate, not
foolproof.
I watched a documentary some time ago showing how they sit in their laboratories for weeks and weeks
studying and deciding just how the flu moves around the world, then make their decision how to mix
the diffrent strains for the 'next' flu shots, very dedicated people.