Alsoo, shihtzulover, think of it this way... are humans vaccinated every year? Or even every few years? No. Gonzo, of course, recieved his puppy shots and is vaccinated every few years, he has been around multiple dogs with kennel cough and never contracted the virus. He gets titers done yearly, which check that his immunity is active. Titers cost 2x more than shots, and most people don't believe in them, so people would rather pump their dogs full of shots every year. I know PLENTY of dogs who contracted kennel cough weeks after recieving their yearly shot, and many dogs who have become sick after getting a massive series of shots all together (bordatella, parvo, rabies, boosters, etc).