I'm sorry your pup had this happen, but I'm glad for you that it was caught and treated. The rabies vaccine is one of the most potent vaccines and the one that carries the greatest risk for reactions. If the pup had a reaction the probability is the reactions will increase in severity with each additional vaccine...So you are right in being worried about this.....This link might be of some help.....
The Rabies Vaccine for Dogs: Side Effects and Precautions You Can Take
I don't know if where you live if they allow for exemptions but it maybe something to think about.....This is a link for each state.....
RABIES LAWS IN THE UNITED STATES as of 6/16/10