I'm really sorry your vet told you that, bc that's just plain false. Overvaccinating *does* harm pets and there are published papers about it. Overvaccination is the reason behind the new vaccine protocols by the AAHA. The vet could have at least given you the choice of titers, which would have told you, at least, if antibodies were present - which indicates past vaccination. Your pup will probably be fine, but what your vet said was really inappropriate, in my opinion.
If you go to this thread, there is some info about vaccines:
http://www.yorkietalk.com/forums/yor...-overview.html