I've always kept my dogs up to date on their shots.....especially rabies...Boomer is still on puppy shots but Cassie is on the 3 year. To my knowledge, they've never had any sort of reaction. We live pretty close to a creek, and I've seen raccoons, skunks, opossums, and, of course, squirrels....I would rather have the peace of mind...I am not really sure if it is the "law" around here or not, but I'm sure animal control would be more apt to put the dog down or something if they didn't have the shot.