1 All 50 US States require a rabies vaccine and the vast majority require dog owners to have the vaccine administered either in a vet's office, at home but under the supervision of a licensed veterinarian, or by animal shelter workers, kennel owners, or other competent individuals who work with dogs professionally. If you have a puppy, it is not safe to vaccinate him before 3 months of age. 2  Most vets recommend vaccinating at 6 months and then again at a year old. 3  Do not vaccinate if you're traveling within a week. 4  If your dog has a serious reaction while traveling, it might be difficult to find medical care on the road.