I forgot to add that the vaccine is still being studied, so any animal that gets it now is a guinea pig.
http://www.medicalnewstoday.com/articles/56910.php
And this site says that this bacteria isn't present in healthy gums but that you still have to brush teeth and get cleanings:
http://www.merrimackvet.com/dent2.htm
Why use a drug when you have to brush anyway?