As responsible dog owners, most of us follow an annual routine. We take our dogs to their vet for their booster shots. In the end, we don’t want them to catch a deadly disease so we vaccinate them against everything there is a vaccine for. And we feel good about it. But wait a minute, I see my primary physician at least once per year and I know for sure that I have not been vaccinated in the past ten years.  So why is it that our dogs need all kinds of vaccinations, once per year, and we do not?

Vaccinations have arguably done more to ensure the health of our dogs than any other advance in veterinary medicine. There is a lot of talk about the potential side effects of vaccinations, but make no mistake, the question should not be whether to vaccinate, but for which diseases, when, and how often.

Essentially, there are two reasons why we vaccinate dogs. We want to prevent our dogs from contracting a potentially life-threatening disease, and we want to ensure that our dogs don’t contract a dangerous disease and then transmit it to us. Globally there are still an estimated 55,000 human deaths from rabies annually, primarily in Asia and Africa.  But does that mean that our dogs need to get annual vaccinations to be protected?  In most cases, they do not!

 

How Vaccinations work

Vaccines are typically made using viruses or bacteria of a disease.  Sometimes, the virus in a vaccine has been killed (e.g. the one in the human flu-shot) and sometimes, it has only been weakened (vaccines containing a modified live virus, or “MLV”).  We use vaccines to introduce a small amount of the disease into the body to stimulate the immune system, which in return will respond by creating antibodies to fight the virus or bacteria. After the antibodies destroy the invading disease, these antibodies remain in the body for some time to provide protection in case the disease ever returns. In addition, information about the invading disease is stored in what we call “memory cells”. This allows the body to quickly re-create antibodies against a disease even years after the first antibodies have disappeared.  This ability to quickly and appropriately respond to an intruding virus or bacteria is what we call “immunity”.

 

Benefits of Vaccinations

Vaccinations have obvious benefits for our dogs. They prevent deadly diseases such as rabies, which is always fatal for unvaccinated animals (usually occurring within 7 to 10 days from when the initial symptoms began). But it is not only our dogs that benefit from vaccinations. The number of rabies-related human deaths in the United States has declined from more than 100 annually at the turn of the century to one or two per year in the 1990’s. More than 90% of all animal rabies cases reported annually to the U.S. Center for Disease Control (CDC) now occur in wildlife. Prior to 1960, the majority was in domestic animals. The principal rabies hosts today are wild carnivores and bats. Animal control and vaccination programs have effectively eliminated domestic dogs as reservoirs of rabies in the United States. In several other countries, including Australia and Japan, rabies carried by terrestrial animals has been eradicated entirely.

 

Risks of Vaccinations

In essence, vaccinations cause a manageable outbreak of a disease. Healthy bodies can deal with it and fight it off, thereby creating the important antibodies that result in immunity against the disease. Fighting the intruding virus however causes a temporary weakness and that can be problematic if the body is already weakened by another disease, or, during such period of weakness, has to deal with a different invading disease. Some vaccination cocktails contain as many as seven different viral diseases and fighting each of them after a shot puts tremendous stress on the immune system, in particular in puppies that have a relatively immature immune system. Poorly attenuated batches of vaccine that revert to virulence and make a dog sick are rare, but they do exist as well. A reaction to a vaccination (known as a ” Vaccination Administration Adverse Event, or VAAE), can be very subtle and manifest itself through loss of appetite, depression, fever, stiffness or pain and swelling at the injection site. Severe VAAE’s include anaphylaxis, a rapidly developing and life threatening allergic reaction against a vaccine. Symptoms may include vomiting, diarrhea, seizures and shock and the affected animal can suffer from cardiac and respiratory failure that can lead to death unless treated immediately and aggressively. Vaccinations can also lead to autoimmune disorders. Autoimmune disorders are essentially disorders of an immune system gone haywire. They arise from an inappropriate immune response against substances or tissue normally present in the body – basically, the immune system mistaking some part of the body as invader and thus attacking its own cells. The likelihood of a dog having an adverse reaction depends upon the type and number of vaccines administered, the dog’s age, genetic predisposition, general health and size. Small dogs are a lot more likely to suffer adverse reactions to a vaccine than large dogs. Also, some dogs and, much more commonly, cats have developed cancers on injection sites (VAS).

In most circumstances, the benefits of immunization clearly outweigh the risk of side effects. This however needs to be evaluated on a case-by-case basis. For example, a dog that is used for hunting or a herding dog that is exposed to livestock and wild animals obviously has a much greater chance contracting a disease than a companion dog that spends most of its time in-house or on a leash. A dog that spends time in boarding or grooming facilities has a much greater chance to contract kennel cough then a dog that does not. A dog that lives in a region with epidemic levels of Lyme infestation (e.g. northeastern United States) has a greater chance to contract Lyme disease while a vaccination against Lyme disease is considerably less useful in areas that only have a small Lyme infection rate. Another consideration is the treatability of the disease itself. While it is obvious why an at-risk dog should be vaccinated against a disease with a high fatality rate, it is questionable why we would vaccinate against a disease that is easily treatable with antibiotics.

 

Vaccination Types

The American Animal Hospital Association (AAHA) divides vaccines into three categories: “core”, “noncore” and “not recommended”.  Core vaccines are those that are highly recommended for every dog because the diseases they immunize against are both widespread and life threatening. Non-core vaccines on the other hand protect against diseases with limited risk of exposure or with good treatability. Not recommended are vaccines with questionable results or, as some veterinarians have called them, vaccines looking for a disease.

Available vaccines are either based on: (a) a killed virus; (b) a modified live virus (MLV) where the virus has been modified to no longer produce a disease but still retains the ability to induce a protective immune response; or (c) recombinants. Recombinant vaccines are made by using bacteria or yeast to create large quantities of a single, purified viral or bacterial protein. One of the advantages of this approach is that your dog cannot get infected from the vaccine as it only contains the protein and not the virus or bacteria itself. Another benefit of recombinant technology is that maternal antibodies that may be present in young puppies cannot inactivate the recombinant vaccine. Puppies get their initial “immunization” through antibodies passed to them from their vaccinated mother. These antibodies are present for the first several weeks of the puppy’s life and they can inactivate MLV or Killed vaccines if they are administered too early (usually before 16 weeks of age).  Another advantage of recombinant vaccines is that they do not include an adjuvant.  An adjuvant is an agent that irritates the dog’s immune system to stimulate a strong reaction against the injected virus or bacteria (in MLV or Killed vaccines). Adjuvants have been implicated in causing cancer.

 

Here is an overview of the most common vaccinations for dogs. (Links open new page with description and and the AAHA recommended immunization schedule):

Canine distemper virus (CDV)
Measles (MV)
Canine Parvovirus (CPV-2) 
Canine Adenovirus Type 2 (CAV-2) 
Canine Adenovirus Type 2 (CAV-2 IN)
Rabies (1 year) 
Rabies (3 year; alternative to 1-year variant) 
Canine Parainfluenza Virus (CPiV) – MLV 
Canine Parainfluenza Virus (CPiV) – IN  
Bordatella (Bb, aka kennel cough) 
Canine Influenza Vaccine   
Borrelia Burgdorferi (Lyme disease)   
Leptospira interrogans
Crotalus atrox (Western Diamond rattlesnake vaccine)
Canine coronavirus (CCoV)

 

Vaccination Frequencies

I had already pointed out that question should not be whether to vaccinate, but for which diseases, when, and how often. In general, the duration of immunity (DOI) to infectious viral and bacterial vaccines is longer than to noninfectious viral and bacterial vaccines, and immunity conferred is generally much longer to viral vaccines than to bacterial vaccines.  In plain English, this means that vaccines based on a modified live virus (MLV) provide a much longer duration of immunity than noninfectious vaccines such as killed virus based vaccines or recombinants.

Noninfectious vaccines
According to the AAHA, annual boosters of noninfectious vaccines are recommended for all dogs that are at reasonable risk of exposure to the infectious agent. The duration of immunity provided by rabies vaccines in dogs that were vaccinated with two initial doses, 12 months apart, is expected to be at least 3 years (when using a 3 year rabies vaccine at the end of the 12 months period).

Infectious vaccines
Infectious core vaccines provide a duration of immunity of over 5 years and up to the life of a dog. Interestingly, the booster recommendation for these vaccines is every 3 years (because when studies show results of 5 years to life, I immediately think 3 years is the right interval…). The AAVA recommendation is made on the basis of “minimum DOI studies over the past 30 years”. These studies were done by all of the major vaccine companies who obviously have a commercial interest in a higher vaccination frequency.  The revaccination of dogs with infectious bacterial vaccines (specifically IN Bb vaccine) is recommended annually.

 

Booster shot or Titer?

When you are driving your car and worry about running out of gasoline, you can stop and refuel or simply look at your fuel gage to see how much gas is left in your tank.  The result of a titer basically is a look at your dog’s immunity “fuel” gage. A titer is a blood test that looks for certain antibodies against a bacterial or viral disease.  If antibodies are present, your dog is protected and no booster shot is necessary.  A major downside of titers is that they are usually a lot more expensive than a simple re-vaccination, but they allow you to minimize the risks associated with vaccinations if they show that your dog is still adequately immunized.

 

Dogisimo Conclusion and Holistic Vaccination Schedule

I hope this article helps to explain some of the thinking behind reducing booster shots. The types and frequency of vaccinations should really depend on your individual situation.  You have to decide for yourself what to do with your dog, but my recommendation is to have antibody titers measured annually instead of simply revaccinating your dog (except where vaccinations are required by law). My dogs are vaccinated based on the following, minimal vaccine protocol below. This protocol is very similar to what is advocated by Dr. Jeanne Dodds, DVM, a homeopathic vet in Southern California.

 

Age of Dog Vaccination
9-10 weeks Distemper, Parvo (MLV)
14 weeks Distemper, Parvo (MLV, same as above)
16-18 weeks Distemper, Parvo (MLV, same as above, optional)
20 weeks or older
if allowable by law
Rabies
1 year after last puppy shot Distemper, Parvo Booster (MLV)
1 year after last puppy shot Rabies, killed, 3-year product (give 3-4 weeks apart from Distemper/Parvo Booster
Thereafter: Distemper/Parvo titers every 3 years thereafter, or more often if desired. Vaccinate for rabies according to the law. If the law permits a written waiver based on positive antibody titer, perform titer and request waiver.

 

Further reading on this subject:

Stop the Shots!: Are Vaccinations Killing Our Pets? by John Clifton

2011 AAHA Canine Vaccination Guidelines

 

 

 

 

 

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