Look up the new AAHA vaccination schedule recommendations. They are now recommending that most of the core viral vaccines, things like parvo & distemper, be given only once every 3 years instead of annually.
There's no denying the protection vaccinations can give our pets, however evidence suggest that these vaccines protect our pets for 7 + years, sometimes even for the entire life of our pet. And yet many vets are still recommending that cats and dogs receive their vaccines annually.
There can be consequences to over vaccinating our pets. They can range from anything from mild allergic reactions to autoimmune diseases and reactions that cause death.
Do your research, become an informed pet owner, and work with a vet you trust to come up with a healthy vaccination schedule for each individual pet. What vaccinations your pet requires can be based on where you live and what diseases are common in your area, and in general core viral vaccines DO NOT need to be given yearly. If you're worried about whether or not your pet is protected, consider having your vet draw a blood sample and run titers.