Do I need to vaccinate my pet?

Your decision to vaccinate your pet depends on several factors:

  • Your pet’s risk of exposure to disease-causing organisms based on your pet’s environment and exposure to other animals
  • Consequences of infection
  • Age and health of your animal
  • Protective ability of the vaccine
  • Frequency or severity of reactions associated with vaccination and any previous reactions  your pet experienced

Why do I need to vaccinate my pet?

The immune system plays a pivotal role in sustaining your pet’s health. One of the critical functions performed by this complex system of specialized cells and molecules is to protect  against disease and infection from viruses, bacteria, and a host of other microbes and parasites.

Vaccines strengthen your pet’s immune system against disease-causing organism. Vaccines contain antigens that mimic disease-carrying organisms to a pet’s immune system. When a vaccine is administered, the immune system mounts a protective response. With this response in place, your pet’s immune system can prevent infection or reduce its severity if your pet is subsequently exposed to a disease-causing organism.

Though vaccines play a critical role in controlling infectious diseases, most do not induce complete protection from disease or provide the same level of protection in all animals. For extra protection, reduce your pet’s exposure to known infected animals or contaminated environments.

Why does my pet require a series of vaccinations?

During the first few hours after birth, kittens and puppies ingest antibodies contained in their mother’s milk. These antibodies protect kittens and puppies from infectious diseases until their own immune system is more mature.

Unfortunately, maternal antibodies interfere with a vaccine’s ability to stimulate a newborn’s immune system. To counteract this problem, veterinarians administer a series of vaccines, starting when the animal is six-to-eight weeks old. Vaccination is then repeated at three- or four-week intervals until the maternal antibody wanes, usually when the pet is 12-to-14 weeks old. Some initial vaccines, such those for rabies, are not given until the maternal antibody disappears completely.


Must my pet be vaccinated every year?

The answer depends in part on the vaccine. For example, certain rabies vaccines provide protection for longer than one year. In this case, vaccination with a triennially approved rabies vaccine can be given every three years (after the initial series is completed and when consistent with local rabies vaccine requirements) is sufficient.

Recent research suggests that panleukopenia, rhinotracheitis, and calicivirus vaccines for cats and distemper, adenovirus, parvovirus, and parainfluenza virus  vaccines for dogs provide adequate protection for several years. As a result, many veterinarians now recommend these vaccines be boostered only once every three years.

Unfortunately, far less is known about the duration of protection provided by other vaccines. Until we learn more, annual inoculations with these vaccines ¾ when their administration is necessary ¾ is a good rule of thumb to follow.


Are vaccines dangerous?

Not usually. Although vaccines are indispensable in fighting many infectious diseases, there is no risk-free vaccine. Like any medical procedure, there is a small chance that reactions can develop from a vaccination. To maximize the benefits of vaccination and minimize risks, vaccinate only against infectious agents to which your pet has a realistic risk of exposure, infection, and subsequent development of disease. Inform your veterinarian about any vaccine reactions experienced by your pet in the past before your pet is vaccinated again.

Reactions may be mild or, in very rare cases, severe.

Mild reactions

The following reactions are common and usually start within hours to several days after vaccination. They typically last no more than a few days.

  • Discomfort at the site where a vaccine was given
  • Mild fever
  • Diminished appetite and activity
  • Sneezing about four to seven days after an intranasal vaccine was given
  • Small, firm, painless swelling under the skin where the vaccine was given. The swelling usually goes away after several weeks, but if you notice such a swelling, contact your veterinarian.

Serious reactions

These reactions occur very rarely:

  • Serious and potentially life-threatening allergic reaction within several minutes to several hours after vaccination. Symptoms include vomiting, diarrhea, facial/throat swelling, and difficulty breathing. Please contact us or an emergency veterinary clinic immediately if any of these symptoms occurs after vaccination.
  • Preliminary studies suggest that in rare cases, vaccinations can induce fibrosarcomas in cats. The rate at which this occurs is estimated to be extremely low, especially with the advent of newer vaccines ¾ only between 1:1000 and 1:10000. No link has been found between vaccination and cancer in dogs.