Another thing to keep in mind when considering the Bordetella vaccine is the fact that the vaccine only covers about 30% of the potential strains.
An analogy is the flu shot. Just because you get a flu shot, it does not mean you won't get the flu. It only means that you have been vaccinated against certain strains.
Here is a nice overview of Bordetella/Kennel Cough:
Kennel Cough - VeterinaryPartner.com