It has long been common practice for dog owners to take their canine companions into the veterinarian's office at least once a year for a regular checkup and vaccinations. Your dog's yearly vaccinations help keep him safe from disease. Accidentally missing your dog's yearly vaccination appointment and allowing your dog's vaccines to expire can have negative consequences.
Vaccinations do not last forever, which is why you have to take your dog back to the veterinarian every year for more shots. Vaccines lose effectiveness over time. Once the vaccine wears off, your dog can once again get sick with the disease the vaccination was supposed to protect him from. Every vaccination manufacturer has guidelines outlining how long the vaccine is considered effective and instructing your veterinarian when your dog will need his next dose to stay protected.
The primary risk your dog faces when his vaccines expire is illness. Vaccines protect your dog from dangerous and potentially fatal diseases such as parvo and rabies. If you allow your dog's vaccines to expire, he could become sick or die as the result of an unnecessary and preventable illness.
Some vaccinations are required by law for dogs. If you allow your dog's rabies vaccine to expire, you could face fines from your community. If your dog bites someone and he is not vaccinated, you may be required to surrender him to your local animal control authority for a mandatory quarantine or disease testing.
If you want your dog to be welcome in dog parks, boarding facilities, grooming facilities and even doggie day cares then you cannot let his vaccinations expire. Canine-based businesses almost always require dogs to be fully vaccinated before they can enter the facility and interact with other dogs. Vaccinations help prevent the spread of disease and a dog with expired vaccinations poses a health risk to all the other dogs at the facility.