One of the most discussed topics in veterinary medicine is that of vaccination. While all veterinarians agree that vaccines are important to the health of a pet, there is disagreement about how often to vaccinate.
Vaccines contain all or part of an organism that causes a particular disease. When a vaccine is given, the body reacts to the organism and the immune system learns how to attack it in the future. However, over time the immunity decreases, required a booster of the vaccine. By boosting a vaccine, we can “remind” the immune system about the organism, giving the pet better protection against a disease.
Newborn animals have not yet had a chance to make their own immunity, but still need protection against infections present in their environment. They receive this immunity from their mother, partly across the placenta before birth, but mostly through the “first milk” or colostrums they drink in the first day or two after birth. Maternal immunity is only temporary. It declines steadily over the first few weeks of life and is largely gone by twelve weeks of age.
Every pet is individual and the levels of antibodies decline at an unpredictable rate. This is why we traditionally vaccinate puppies or kittens at 8, 12, and 16 weeks of age. The pet will be seen one year after the last puppy or kitten visit to boost all the vaccines.
What is somewhat more controversial is when to further boost the vaccines as the pet becomes an adult. Generally, veterinarians follow the instructions provided by the vaccine manufacturer. Some vaccines have been tested to be effective for up to three years, while some are only proven for one year.
Some pet owners chose to have the pet’s annual physical exam done routinely, but instead of vaccinating, a blood sample is collected and tested for the level of specific antibodies. This is called titre testing, and indicates the level of the pet’s immunity. The titre levels help to guide the owner and veterinarian as to when the pet’s vaccines need to be boosted next.
Titre testing is only available for certain viruses, and is more expensive than vaccinating. If the titre is low, then the pet will need to have those vaccines boosted anyway.
Keep in mind that immunity is not absolute. Immunity (as reflected by an adequate titre level) can sometimes be overcome when there is:
- an overwhelming exposure to a high dose of a virulent or particularly harmful strain of the microorganism
- a higher level of stress (i.e. – boarding, travel, high anxiety pets)
- an already weakened immune system due medical conditions, diseases, or from fighting other infections
- a history of immuno-suppressive medication, such as a steroid.
Every pet and every family is different. A veterinarian’s duty is to educate a pet owner and present appropriate courses of action. Please consult your veterinarian to determine how to effectively maintain your pet’s health.