I have had pups with that same reaction...I don't believe it is considered a life threatening anaphylactoid type reaction; but it is very disconcerting. They usually have the discomfort for 24 hours and then they are fine. It is interesting that your vet gave a name for it...I am going to look that one up. I did not have a name given to me. Scared the heck out of me the first time it happened.
As for immunizations, my vet follows the AAHA recommendations:
http://www.aahanet.org/publicdocumen...s06revised.pdf