For how much time does rabies vaccine provide protection? i think i was scratched by a stray dog.

Wash First: Clean the scratch with soap and water for a good 5 minutes--then head to emergency room. Even vaccinated you may still need rabies vaccine, just not as many doses and just no rabies immune globulin. While dogs are less risky as rabies carriers they are making a comeback in some areas. This is a decision that will have to be made at a local level, with the involvement of your animal control office.