1. The only vaccine required by U.S. law is rabies. 15 states currently offer exemptions to animals with serious health problems and more are adding exemptions. Not all states require cats and ferrets to be vaccinated. Note: because laws change with little fanfare, not all veterinarians know the current regulations. Click here to see a list of U.S. state laws. Double check with your city and county Animal Control.
2. There is little or no research showing that annual revaccination for core vaccines boosts immunity. Studies do show that core vaccines shouldn’t be given any more frequently than every three years — not every three years.
3. Mature dogs and cats rarely die from vaccine-preventable infectious disease and thus may not need vaccinating.