What is a vaccination?
Vaccinations are often the primary reason why a pet is brought to the veterinarian. At the Animal Hospital of Chetek and Animal Hospital North we hope to break that tradition. We hope our clients will bring us their pets to keep them healthy and to discuss what their pets need. We strongly believe that there is no one size fits all approach to vaccinations. Vaccines are best prescribed based on lifestyle, age, and risk.
Vaccinations, or immunizations, are injections of antigens designed to stimulate the immune system to protect the body against invasion by a specific disease causing agent. The antigens carried in vaccines are similar enough to the actual disease that they will trigger an immune response, but they are slightly altered so that they should not cause the disease they are designed to protect against.
When a vaccine is introduced by injection or some other means, the immune system responds by creating antibodies towards that disease. When the animal is later exposed to the disease in the environment there are already antibodies present to destroy the disease before it can cause any damage.
If the animal was not vaccinated for that disease it will still develop antibodies. However, it takes time to develop antibodies and while the immune system is busy producing antibodies the disease is wreaking havoc within the body, weakening the animal and making it harder for the immune system to function properly.
Why does my pet need multiple vaccinations?
All puppies and kittens have maternal antibodies passed along to them from their mother when they first begin to nurse. These maternal antibodies do not last forever. If maternal antibodies are present at the time the puppy or kitten is vaccinated then the maternal antibodies will destroy the antigens before their immune system can create its own antibodies. This is why puppies and kittens are vaccinated multiple times.
Because every animal is different we cannot know exactly when maternal antibodies are no longer present. Some puppies and kittens will lose maternal antibodies as early as six weeks of age, while others may maintain maternal antibodies until 16 weeks of age. We give vaccinations at 8, 12, and 16 weeks of age to ensure that all animals are always protected during an age when they are most vulnerable and to reasonably ensure maternal antibodies are not interfering with the immune response at the time of their last puppy/kitten vaccination.
If your pet no longer had maternal antibodies at 8 weeks of age, and was vaccinated at 8, 12, and 16 weeks of age your pet would simply have more antibodies present against the disease then a pet whose maternal antibodies lasted until 16 weeks of age. This is because of memory cells within the immune system. Memory cells remember antigen exposure, and when the same antigen is seen again they rapidly produce additional antibodies.
Some vaccinations, such as rabies, have been tested extensively by their manufacturer and have been certified by the USDA to provide immunity with only one vaccination.
Animals are then vaccinated annually because over time active antibody levels will decrease. Fortunately memory cell numbers do not decrease significantly and receiving a booster 1-3 years later (depending on the vaccine) will increase the active antibodies to protective levels.