I have been vaccinating my hounds since the vaccine hit the market. While I do not believe that it can save a dog that is hit in the chest by a "hot" snake, especially if the dog is stressed from a hard race or activity. I get a least one dog a year struck by a rattler and the vaccine seems to reduce the amount of swelling/infection.
Wow one a year!! That's nuts. I took my dog to one of Wayne's clinics last year and thankfully didn't see any snakes she's very cautious of her surroundings now it seems, I will start getting the vaccines from now on and keep taking her for these clinics and just hope she or I never get bit.