The only yearly vaccination my pet gets is the rabies since it is required here in our place. Other than that, I just have my pet regularly checked-up. I have read this: " That the immune system has a "memory." The immune system contains memory cells. Once those memory cells have been shown what to do against a particular disease (by one puppy vaccination at 11-16 weeks old), they will produce antibodies against that disease whenever they encounter it -- for years and years, probably for life. " You can check it out at http://www.yourpurebredpuppy.com/health/articles/puppy-shots-and-dog-vaccinations.html