Lauren M. Silvesti, DVM, VCP

There is a new shift in the veterinary community, a shift that many people in the animal care industry have known needed to take place years ago, but now at least is becoming more and more mainstream. To put it bluntly, we have been over vaccinating our pets. There is no doubt that vaccinations have served to decrease the prevalence of serious, life threatening diseases. However, questions have arisen to the need for yearly vaccinations, as well as to the need for life-long vaccinations because of possible long-term consequences. (Every animal patient is an individual and the following summary should only be used as a guideline as situations and environments vary drastically.)

We should begin with the question "What is a vaccine?" A vaccine is a suspension of infectious agents or part of them that is injected into an animal to stimulate the immune system to produce antibodies to the disease. Upon exposure to the disease, the antibodies quickly react to detect and destroy the virus. Vaccines were developed as a much-needed answer to widespread life-threatening viral diseases such as parvo, distemper and panleukopenia (feline distemper). However, they soon evolved into multi-vaccine "cocktails" that were given to every pet regardless of the actual risk for disease as a "just in case" measure. Shelter animals, breeding animals and house pets were all treated the same.

What is not taken into consideration with the "good for one, good for all " approach is that:
1) Some vaccines are unnecessary as the actual disease itself is not life threatening. Corona virus is a relatively mild disease of puppies and therefore should only be administered to kennels or litters where the virus is endemic. Chlamydia is a similarly mild upper respiratory tract infection of cats and responds to medical treatment if infected.

2) Vaccines may cause immunosuppression or interactions. There is much debate over recent evidence that over vaccination causes immunosuppression and allows other acute and chronic diseases to take hold. One very common disease that can be aggravated by "shotgun" vaccination is ALLERGY. Allergies are a manifestation of constant overload of vaccines, food preservatives, environmental chemicals and medications. The body finally reaches a point where it is unable to cope with the additional challenges and allergies are expressed. Many other diseases including hypothyroidism, epilepsy and immune suppression may have some links with over vaccination.

An important study in England of 2,700 dogs has shown that "the incidence of illness in dogs treated with more than one vaccine at a time is significantly higher than when only a single vaccination id administered. This study also reported that dogs annually boosted were more likely to become ill than those that were not boosted annually. Illnesses reported at an average of 55% higher level than ' expected in the first 3 months following a vaccination was: Diarrhea, epilepsy, loss of appetite, nasal discharges, skin problems, vomiting, weight loss, behavioral problems, tumor growth at vaccination site, encephalitis, lameness, short attention span, autoimmune diseases, dry eye, and others.

3) Some vaccines that were once protective are no longer useful in preventing disease. Leptospirosis bacterins currently contained in vaccines are not protective against the serovars that are causing the disease and immunity is very short lived (few months). There have been very few clinical cases of infections canine hepatitis from adenovirus 1 yet all polyvalent vaccines contain adenovirus 2 to elicit cross protection.

Many people assume that vaccines are 100% effective in preventing disease. This is simply not the case. As stated in the definition of a vaccine, the IMMUNE SYSTEM determines the effectiveness of a vaccine. A weak, sick or otherwise unhealthy animal may not mount a proper defense. The "puppy series" is designed to counteract another possible failure of vaccines- interference of the mother's antibodies that were consumed in her milk. We vaccinate at regular intervals during the period of time where the puppy may or may not be protected by its' mothers antibodies. Since this interval varies with every puppy, we give several shots to insure protection. There are a multitude of other possibilities of failure that rarely occur including improper handling of vaccines, (not refrigerated properly), or not given on a proper schedule.

Another assumption by many pet owners is that vaccines are 100% safe. Although rare, serious and life threatening complications such as anaphylactic shock can occur to one or more vaccines. Other milder reactions such as soreness at the injection site, lack of appetite, lethargy (lack of energy) can also occur. To better document these reactions and pinpoint the exact vaccine that caused the reaction, I routinely try to give only one vaccine per visit where possible. In case of reactions, we are now able to eliminate that vaccine from our wellness protocol and use other alternatives like serum antibody liters to document protection.

After reading this information, it is easy to get scared and say, "Why vaccinate at all?" This would be a mistake as well. Reaching a balance is critical. We now know that vaccines carry risks but now there are New Guidelines offered by such organizations as the American Association of Feline Practitioners to try to reach the optimum balance of protection and wellness.

The New Guidelines:
1) Puppies and kittens should be vaccinated against the clinically important CORE infectious diseases (Distemper virus, Parvovirus, Panleukopenia (feline distemper) and rabies)

2) Vaccinations should be avoided before 6 weeks of age and then given 2-4 doses at 2-4 weeks apart (Some breeds like Rotties, Dobies, and Labs, Pomeranians and American Staffordshire Terrier should be vaccinated for longer intervals since they have difficulty mounting an immune response against parvovirus)

3) Booster vaccinations should be given at one year of age. Thereafter boosters should be given at 3-year intervals.

4) Antibody titers can be checked in between boosters to check for "adequate immune memory" (The term protective immunity is not used as we cannot equate antibodies with protection against disease). Animals with measurable serum antibody titers should be rapidly able to mount an adequate immune response to afford protection upon exposure.

5) Geriatric animals (9 years + generally DO NOT need booster vaccinations) Vaccines may also be unadvisable in animals with aging or immunologic disorders. This includes dogs with symptoms of any illness or medical condition during their physical exam (mild ore severe) ranging from skin conditions to lameness to cancer, dogs undergoing surgery, pregnant bitches or dogs on immune suppressing drugs.

6) Efficacy and side effects can depend on the BRAND of vaccine given.

What about the Non-Core vaccines? Lyme vaccine may not be required in all geographic regions (although I do recommend it for central PA in dogs that are heavily exposed to ticks). Use of Feline Leukemia vaccines should be reserved for cats that live mostly outdoors or in catteries where new animals are encountered regularly. The Leukemia and Rabies vaccine have been implicated in the majority of injection site fibro sarcomas. The USDA licenses rabies vaccines for 3 years. I believe any interval less man this required by states or townships is frankly unjustified, especially for our spoiled house pets that are not even contacting potential carriers. Not to mention that those animals most at risk, primarily farm cats and dogs, are not required to be vaccinated.

If you are still not convinced by now, just think how often humans are vaccinated. The process of the ANNUAL vaccination has no scientific validity or verification. It was simply a chosen interval for bureaucratic licensing by the USDA some 25-30 years ago. The interval was chosen as more of an incentive for pet owners to schedule their yearly exam, far more important in extending an animal's life span than the vaccines. A renowned veterinary text, Kirk's Current Therapy states "it is TIME TO CHANGE", "to do what is best for the animal" and above all " only HEALTHY, CLINICALLY NORMAL animals should be vaccinated.

In summary, concern for the INDIVIDUAL pet should be the motivation for reaching a conclusion about vaccination. I have personally witnessed puppies die of parvo and the feeling is of pure helplessness. One must remember that vaccination is only ONE SMALL PART of reaching overall wellness. We have always known that vaccinations are not 100% effective. Support of the immune system with nutrition, preventive measures, excellent sanitation and management is also critical.

Reducing the Risk

1) Measure antibodies through serum antibody liter tests and only vaccinate when indicated by low titers. These tests are not going to save the pet owner any money and they should still be performed annually until we know more conclusively how long these antibodies last in the blood. However, these tests give us peace of mind that we are not doing unnecessary procedures as well as helping the veterinary community establish just how long vaccinations actually protect the average dog or cat. This knowledge may save many thousands of pets in the future from unnecessary illnesses.

2) Reduce the incidence of booster shots to every 3 years after me first annual booster.

3) Don't give several shots at one time. Try when possible, to give individual vaccines instead of "cocktails". (We are working hard at Progressive Pets to carry these products in the very near future)

4) Watch your dog closely for several weeks following vaccination to look for reactions that might influence future vaccine decisions. Any problems including seizures, ear infections, or even a simple hot spot should be reported to the veterinarian.