Lifelong Immunity And The AAHA Revaccination Guidelines

Dogs Naturally

Earlier this month we published a blog post that got a lot of attention.  Lifelong Immunity – Why Vets Are Pushing Back was shared around the world by tens of thousands of people.  The article questions why vets are still vaccinating annually or triennially when vaccines were shown to last at least seven years, and likely for the life of the animal – research that was done over thirty years ago.

It seems that the article also got the attention of the AAHA and their PR Manager responded to the article publicly.  We would like to post his response here and take a look at the AAHA Vaccination Guidelines.  Here is the comment we received:

Hello, my name is Jason Merrihew, PR manager for the American Animal Hospital Association (AAHA). We understand the concerns of pet owners regarding risks associated with vaccines. This is why AAHA first developed guidelines in 2003. With advancements in research and new vaccines, our canine vaccine guidelines were revised in 2006 and most recently, updated in October of 2011 (these guidelines are made public at The above article incorporates research and feelings from 1995-2003. The views of the veterinary profession have evolved since then due in part to the AAHA guidelines as well as advancement in research. Vaccines are very important to the health of our loved ones (both 4 and 2 legged). If they are administered properly and the individual lifestyle/location of each individual pets is taken into account, vaccines are very effective in protecting pets and humans from serious illness and sometimes death.
Jason Merrihew
AAHA PR Manager

Here is a little history behind the AAHA Vaccine Guidelines:

In the 1970s, all vaccines, with the exception of rabies vaccines, were licensed by the United States Department of Agriculture (USDA) based on challenge studies performed from only a few weeks to a few months after vaccination. All the vaccine labels included the statement ‘‘Annual Revaccination Recommended’’ without the knowledge of whether the true duration of immunity (DOI) was a year or a lifetime.  So vets vaccinated yearly, even though field observation suggested that immunity after both natural infection and vaccination was long lived.

In the mid 1970s, Drs Ronald Schultz et al questioned this and began doing research into the DOI of vaccines.

“My interest in vaccine DOI was stimulated by several factors” says Dr. Schultz.” (1) the observation that dogs who had recovered from canine distemper and cats who had recovered from panleucopenia were completely resistant to experimental viral challenge many years later; (2) that my three children were receiving a series of vaccinations that would end about the time they entered school with most of the vaccines never being given again; (3) a veterinarian in the US Army Veterinary Corps asked me to design a vaccination program for dogs and cats that did not require yearly revaccinations; (4) it was not known if yearly vaccinations were necessary for dogs and cats, but most experts I consulted believed they probably were not needed”.

“Based on our observations and existing knowledge of duration of immunity following natural infection and/or vaccination we published An Ideal (But Not Proven) Immunization Schedule for Dogs and Cats in 1978. We recommended a series of puppy/kitten vaccinations followed by revaccination at 1 year, then revaccination every 3 years.

Research was initiated at this time to prove his suspicions and dogs where challenged with exposure to distemper, adenovirus and parvovirus, anywhere from 1 to 11 years after vaccination.  Every single dog was protected when exposed to the virus.  “The results from this limited group of dogs clearly demonstrated the Norden modified live vaccines provided immunity for at least 11 years against CDV and CPV-2” says Dr. Schultz.  Based on this research, Drs Schultz and Scott recommended triennial revaccination instead of annual revaccination.

These early recommendations prompted the AAHA to assemble a task force.  In 2003, the American Animal Hospital Association Canine Vaccine Task Force evaluated the data from these challenge and serological studies and, while noting that the core vaccines had a minimum duration of immunity of at least seven years, compromised in 2003 with the statement that “revaccination every 3 years is considered protective.”

Task force member Dr Richard Ford, Professor of Medicine, North Carolina State University, said that the decision to recommend a 3 year revaccination schedule for core vaccines was a compromise. “It’s completely arbitrary…,” he said. “I will say there is no science behind the three-year recommendation…”

After the 2003 task force, all of the major veterinary vaccine manufacturers completed their own studies showing a minimum 3 year DOI on the core vaccines – distemper, parvo and adenovirus.

Dr Schultz continued with his work and by 2006, had performed seven additional DOI studies on over 1,000 dogs and repeated the same results over and over again, effectively showing that dogs were protected for much longer than three years and most likely for the life of the dog.

In fact, so sure was Dr Schultz of his work, that his own vaccination protocol for his dogs was one shot of distemper, parvo and adenovirus and none thereafter.

By 2006, vaccine labels had changed to reflect a longer DOI and the AAHA released their revised Canine Vaccine Guidelines. These guidelines were updated again in February 2007 to include new information about parvovirus and distemper vaccination.  Nearly thirty years after Dr Schultz’ initial research, the AAHA decided to change their revaccination recommendations for core vaccines from “revaccination every 3 years is considered protective” to “revaccination every 3 years or more is considered protective.”

Dr Schultz continues with his research and his results are repeated time and time again.  In the meantime, research is increasingly showing the deleterious effects of vaccines and this has not escaped the AAHA’s notice.

In 2011, the AAHA updated their Canine Vaccination Guidelines once more.  Here is the progression of the recommendations, ending with the 2011 recommendation:

2003:  “revaccination every 3 years is considered protective”

2006:  “revaccination every 3 years or more is considered protective”

2011:  “every 3 years or more” with the following comment: “Among healthy dogs, all commercially available [core] vaccines are expected to induce a sustained protective immune response lasting at least 5 yr. thereafter”

Back in 2003, the AAHA Task Force advised vets of the following in regard to their 3 year recommendation: “This is supported by a growing body of veterinary information and well-developed epidemiological vigilance in human medicine that indicates immunity induced by vaccination is extremely long lasting and, in most cases, lifelong.”

Eight years later, they still recommend every 3 years or greater. As Dr Ford stated, compromises are clearly being made, judging by the AAHA’s arbitrary and slow-to-evolve revaccination recommendations.

What could be holding the AAHA back from making stronger statements or stronger enforcement policies?

The AAHA is sponsored by four vaccine manufacturers: Merck, Merial, Pfizer and Boehringer Ingelheim. Furthermore, the veterinary members of the task force certainly have a vested financial interest in how often vaccines can be delivered. 

Is this a potential conflict of interest and could this create bias in the task force recommendations?

The problem with compromise is that nobody really wins.  This includes our dogs.  It is taking vets years to move away from annual vaccination – a practice that was started without any scientific evidence.  If there was any scientific precedent for annual revaccination, the AAHA’s careful and gradual move away from this practice would be understandable.  But the only research behind vaccines shows an efficacy of at least 7 years for the core vaccines – there is and never has been any evidence to the contrary.  When we look at the AAHA guidelines with that in mind, it makes one question why three years and why five years?

As dog owners – and the people who are financially and emotionally responsible for the effects of over-vaccination – we deserve better than this.  Until the AAHA stops compromising and catches up to current vaccine efficacy research, the most important compromise could be our dogs’ health and welfare.

Please share this article with concerned dog owners.  If change will not happen from within, then we must make change happen.

“The truth is the majority of vets are not going to change until they are forced to – which is not likely to happen due to politics and due to the lack of concern by the one entity that could protect the public and ensure animal welfare:  the individual state veterinary medical boards,” says Dr Patricia Jordan. “This change will have to come from the public, they have to stop allowing the over servicing; they need to start filing law suits when their pets are manipulated and when their purses are raided.”

* Here is the list of adverse events known to be induced via vaccine administration (Schultz, 2007):

Common Reactions:

  • Lethargy
  • Hair Loss, hair color change at injection Site
  • Fever
  • Soreness
  • Stiffness
  • Refusal to eat
  • Conjunctivitis
  • Sneezing
  • Oral ulcers

Moderate Reactions:

  • Immunosupression
  • Behavioral changes
  • Vitiligo
  • Weight loss (Cachexia)
  • Reduced milk production
  • Lameness
  • Granulomas/Abscesses
  • Hives
  • FacialeEdema
  • Atopy
  • Respiratory disease
  • Allergic uveitis (Blue Eye)

Severe Reactions triggered by Vaccines:

  • Vaccine injection site sarcomas
  • Anaphylaxis
  • Arthritis, polyarthritis
  • HOD hypertrophy osteodystrophy
  • Autoimmune Hemolytic Anemia
  • Immune Mediated Thrombocytopenia (IMTP)
  • Hemolytic disease of the newborn (Neonatal Isoerythrolysis)
  • Thyroiditis
  • Glomerulonephritis
  • Disease or enhanced disease which with the vaccine was designed to prevent
  • Myocarditis
  • Post vaccinal Encephalitis or polyneuritis
  • Seizures
  • Abortion, congenital anomalies, embryonic/fetal death, failure to conceive

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