In most states in America, Rabies vaccine for dogs is required by law! It usually administered to the dog when it reaches the age of four months. Moreover, when the dog reaches one year of age, it is usually given what is called a booster to make the rabies vaccine stronger.
Rabies is viral, and it is transmitted mostly through bites. It can also hurt humans. Vaccinating your dog, therefore, protects it protects as well.
It is painful and ugly to have, causing inflammations in the spinal cord and the brain, and eventually crashing the whole nervous system. A rabies-infected do will most likely die, so vaccinate your dog against rabies.