Pet Vaccine FAQs

The American Animal Hospital Association has published guidelines for vaccinations in dogs and cats, and vaccines are divided into two categories – Core and Non-Core vaccines. Core vaccines are vaccines that are recommended for every patient, regardless of environment and lifestyle. Non-Core vaccines should be given to a patient based on their individual risk of exposure to that disease.

Canine Core Vaccines: Distemper Virus, Adenovirus Type 2, Parainfluenza Virus, Parvo Virus, & Rabies.

Canine Non-Core Vaccines: Kennel Cough/Bordatella & Leptospirosis. For more information about these diseases, please see the “Canine Non-Core Vaccines” on our Forms page.

Feline Core Vaccines: Feline Viral Rhinotracheitis, Calicivirus, Panleukopenia, and Rabies.

Feline Non-Core Vaccines: FELV (Feline leukemia virus) & FIV (Feline immunodeficiency virus). For more information about these diseases, see the “Feline Non-Core Vaccines” on our Forms page.

Vaccines do not directly protect our pets but rather stimulate the immune system to respond by producing antibodies and cell-mediated responses that protect the pet against viruses and bacteria. The pet is most protected 2 – 3 weeks after a properly-timed and administered vaccine. In addition, when a vaccine against a specific disease is given for the first time, even in an adult animal, it is best to give a booster vaccine 2 – 4 weeks later as the second vaccine will produce an exponentially greater immune response.

When a baby kitten or puppy is born, its immune system is immature, leaving it vulnerable to infection if exposed to diseases. During the first few days of nursing, the puppy or kitten receives mother’s milk called colostrum which is rich in all the antibodies the mother has to offer. How long this maternal antibody lasts in a given pet is very individual and depends on a variety of factors.

What we do know about maternal antibody is that it starts to wane as early as 6 weeks of age, and is completely gone by 16 weeks of age. The puppy or kitten’s body must then depend on its own antibodies for protection. While maternal antibodies are in a puppy or kitten’s body, any vaccine given will be inactivated and will not result in antibody production or protection for the pet.

Because it takes one vaccine and then a booster vaccine 2 – 4 weeks later to provide adequate antibody production in an individual animal, our goal with a series of vaccines is to provide two effective (not inactivated by maternal antibody) vaccines, 2 – 4 weeks apart, during the period of time when the maternal antibody is leaving their body and their own immune system is able to respond. That said, it is not the number of vaccines given in the series that is important (it only takes two), but the period of time over which the vaccine series is given that is important.

Vaccines are licensed to give only to healthy, non-infected pets. If a vaccine is given to a sick, febrile or infected pet, the vaccine may not provide protection and may make the pet sicker by tying up their immune system so it can’t fight the infection that is already present. We do a thorough physical exam on all patients presented for vaccines to ensure the pet is healthy and that the vaccine will be safe and effective.

Some muscle soreness, lethargy, and mild fever persisting for 24 – 48 hours are considered common and normal reactions to stimulation of the immune system secondary to vaccination. Anything longer than this should be discussed with your veterinarian.

Vaccines are biological products and as such can result in adverse reactions in some patients, although these are uncommon. Since the original development of vaccines more than 50 years ago, a continuing effort has been made to make vaccines safer and more efficacious. Today, vaccines have an excellent safety record and adverse reactions are very uncommon.

To date, there is no data available to provide information on the true incidence of adverse reactions to vaccines in companion animals, although we know that genetics, breed, size of the animal, and the number of vaccines given at one time may play a role. For this reason, we may recommend that if multiple vaccines are indicated for a certain pet, we want these vaccines to be given at separate visits to minimize this risk. Adverse reactions to vaccines include immediate anaphylactic shock, or less severe symptoms such as vomiting, diarrhea, facial swelling, or hives from a few hours to a few days after vaccines. If any of these symptoms should occur, please discuss this with our veterinarian.

Many people have speculated that annual vaccination is responsible for cancer, immune-mediated diseases, kidney disease, and other common ailments in older dogs and cats. To date, there is no clear evidence that vaccination has increased the incidence of any of these specific health problems.

In cats, fibrosarcomas (aggressive, malignant skin tumors) have been found to grow in areas of the body where vaccinations are routinely administered, although these tumors can also occur spontaneously independent of vaccinations. The FELV and Rabies vaccines have been implicated in this type of tumor growth, and the adjuvants (or carriers) of the vaccine specifically have been suspect. The reported incidence of vaccine-associated fibrosarcomas is anywhere from 1 in 1,000 to 1 in 10,000 cats which is rare relative to the incidence of the diseases that we are vaccinating against. In an effort to minimize your cat’s risk of fibrosarcoma, we use vaccines that have no adjuvant, minimize the frequency of vaccines given by using 3-year vaccines when possible and only vaccinate your pet against diseases they are at risk of being exposed to. We also administer vaccines in specific locations of the body where should a tumor occur it could be most easily removed surgically.