Personally, I think we ought to wait until there is an attack. I understand if you are vaccinated immediately after exposure it works as well. There are many side effects to the vaccinations and it's just plain silly to take something until you need it.
We should make absolutely sure that there is sufficient vaccinations available in the event of an attack though.
I'll be happy if I can just get a darn flu shot next year. (Providing, of course, that they vacccinate for the right darn strain...)