Lifelong Immunity – Why Vets Are Pushing Back

lifelong immunity

Did you know your dog’s (and cat’s) vaccines last a lot longer than 3 years? In fact, most pet vaccines protect for a minimum of 7 to 15 years.

Immunology research proved this fact decades ago. Yet many veterinarians continue to insist on you vaccinating your dog at least every 3 years. Some even push for annual shots. But there’s no scientific basis for these practices. 

Vaccine Research

Veterinary immunologist Ronald Schultz PhD chaired the University of Wisconsin’s Department of Pathobiological Sciences. He spent his career as a veterinary immunologist at the forefront of vaccine research.

The vaccines Schultz studied include …

  • Canine distemper vaccine
  • Canine parvovirus vaccine
  • Feline panleukopenia vaccine
  • Rabies vaccine
  • Feline rhinotracheitis
  • Feline calicivirus

In a 1999 paper, Dr Schultz outlined the duration of immunity for several vaccines. In other words … how long they will protect your pet.

Minimum Duration Of Immunity For Canine Vaccines

Here’s the minimum duration of immunity for common vaccines. (Challenge means the researchers exposed the animal to the disease and serology means they measured blood antibody levels.)

Distemper – 7 years by challenge/15 years by serology
Parvovirus – 7 years by challenge/7 years by serology
Adenovirus – 7 years by challenge/9 years by serology
Canine rabies – 3 years by challenge/7 years by serology

Dr Schultz concluded …

“Vaccines for diseases like distemper and canine parvovirus, once administered to adult animals, provide lifetime immunity.” 

And yet many vets continue to vaccinate annually. Dog owners even feel they’re lucky if their vets vaccinate every 3 years instead of every year. But why do we allow it? This information has been available for about 30 years. And researchers have replicated the studies time and again.

RELATED: What you need to know about the distemper vaccine …

Other Immunologists Agree

Another prominent immunologist, Ian Tizard BVMS ACVM ScD PhD authored the standard textbook on Veterinary Immunology. 1998 research by Tizard states:

“With modified live virus vaccines like canine parvovirus, canine distemper and feline panleukopenia, calicivirus and rhinotracheitis the virus in the vaccine must replicate to stimulate the immune system. In a patient that has been previously immunized, antibodies from the previous vaccine will block the replication of the new vaccinal virus. Antibody titers are not significantly boosted. Memory cell populations are not expanded. The immune status of the patient isn’t enhanced.

After the second rabies vaccination, re-administration of rabies vaccine does not enhance the immune status of the patient at one or two year intervals. We do not know the interval at which re-administration of vaccines will enhance the immunity of a significant percentage of the pet population, but it’s certainly not at one or two year intervals.”

In plain English … this means that vaccinating more often doesn’t make your pet more immune! So why do veterinarians stick to this pointless schedule?

A Harmful Practice Since 1978

Dr Schultz commented …

“The recommendation for annual re-vaccination is a practice that was officially started in 1978. This recommendation was made without any scientific validation of the need to booster immunity so frequently. In fact the presence of good humoral antibody levels blocks the anamnestic response to vaccine boosters just as maternal antibody blocks the response in some young animals.”

And he warned …

“The patient receives no benefit and may be placed at serious risk when an unnecessary vaccine is given. Few or no scientific studies have demonstrated a need for cats or dogs to be revaccinated. Annual vaccination for diseases caused by CDV, CPV2, FPLP and FeLV has not been shown to provide a level of immunity any different from the immunity in an animal vaccinated and immunized at an early age and challenged years later. We have found that annual revaccination with the vaccines that provide long-term immunity provides no demonstrable benefit.”

So the expert veterinary immunologists are very clear. Why then, have vets not embraced the concept of lifelong immunity in dogs?

Is It About Money?

It’s easy to suspect profits are at the root of vets’ resistance to update their protocols. Without vaccines, clients might be less inclined to make yearly veterinary visits. The American Animal Hospital Association (AAHA) reports that vaccine revenues are about 15% of the average practice’s income. So veterinarians stand to lose big.

“I suspect some are ignoring my work,” says Schultz. “Tying vaccinations into the annual visit became prominent in the 1980s and a way of practicing in the 1990s. Now veterinarians don’t want to give it up.”

Another noted immunologist, Dr Richard Ford, Professor of Medicine, North Carolina State University, said …

“Both the AAHA and the AVMA must do more to step up to the plate,”

But the reality is the vets don’t have to listen to the AAHA or the AVMA. The state veterinary medical boards don’t seem to enforce vaccine schedules, leaving it up to the individual vets. And they’re clinging to their old ways.

Dr Bob Rogers hired a Chicago-based law firm and initiated a class action suit for pet owners who weren’t given informed consent and full disclosure prior to vaccination administration. His article “The Courage to Embrace the Truth” states …

“While attending conferences like WSVMA and NAVMC I have asked over 400 DVMs from various parts of the country if they attended the seminars on New Vaccination Protocols. I was told by all but one, “I don’t care what the data says, I am not changing.” One DVM here on VIN even said “I am not changing until the AVMA makes me change.”

The AAHA Response

When we first published this information, it caused quite a stir. We also got the attention of the American Animal Hospital Association. Their PR Manager responded to the article publicly. Here’s part of his response:

“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.”

So, let’s look at the history behind the AAHA Canine Vaccination Guidelines. And you’ll see how much (or little) they’ve “evolved since then.”

History Of AAHA Vaccination Guidelines

In the 1970s, the United States Department of Agriculture (USDA) licensed all vaccines, with the exception of rabies.

They based their recommendations on challenge studies performed from only a few weeks to a few months after vaccination. So they didn’t know how long immunity really lasted. Field observation suggested that immunity after both natural infection and vaccination was long-lived.

But anyway, all the vaccine labels included the statement ‘‘Annual Revaccination Recommended.’’ So vets vaccinated yearly.

In the mid 1970s, Dr Ronald Schultz and others questioned this practice. So they began doing their research into vaccine DOI. Here was their 1978 recommendation …

“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.”

So even then, more than 40 years ago, Dr Schultz believed that revaccination every 3 years was enough.

2003 – Enter The AAHA

The DOI research prompted the AAHA to form the AAHA Canine Vaccine Task Force. 

They evaluated the data from challenge and serological studies. In 2003 they noted that the core vaccines had a minimum DOI of at least 7 years. But still, they made the statement “revaccination every 3 years is considered protective.”

Task force member Dr Richard Ford 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.”

The Task Force clearly acknowledged their compromise in the following information for vets:

“Misunderstanding, misinformation and the conservative nature of our profession have largely slowed adoption of protocols advocating decreased frequency of vaccination.

Immunological memory provides durations of immunity for core infectious diseases that far exceed the traditional recommendations for annual vaccination.

This is supported by a growing body of veterinary information as well-developed epidemiological vigilance in human medicine that indicates immunity induced by vaccination is extremely long lasting and, in most cases, lifelong.”

2006 AAHA Findings

Dr Schultz continued with his work. By 2006 he’d done 7 additional DOI studies on over 1,000 dogs. He’d achieved the same results over and over again. The research still showed dogs had protection for much longer than 3 years … and most likely for the life of the dog.

In fact, Dr Schultz was so sure of his work, that his vaccination protocol for his own dogs was: one shot of distemper, parvo and adenovirus and none thereafter. That’s it … “one and done.”

By 2006, manufacturers changed the vaccine labels to reflect a longer DOI. So, in 2007 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 continued with his research and repeated his results time and time again. And research increasingly showed the harmful effects of vaccines. This didn’t escape the AAHA’s notice.

2011 AAHA Update

In 2011, the AAHA added this comment after “every 3 years or more”

“Among healthy dogs, all commercially available [core] vaccines are expected to induce a sustained protective immune response lasting at least 5 yr. thereafter.”

But still vets push 3-year vaccines. And here’s where the AAHA is today.

2017 AAHA Guideline

The current Guideline (in 2021) is from 2017. Instead of increasing the time for re-vaccination, the AAHA seems to be stuck.

“Administer subsequent boosters at intervals of 3 yr or longer.”

They don’t even have the comment about 5-year protection anymore. But they do now contemplate doing titers instead of vaccinating. They added this statement (along with some information about titers) …

“Measuring antibody levels (quantitative or qualitative) provides a reasonable assessment of protective immunity against CDV, CPV, and CA.”

And the Remarks include these words …

“Following completion of the Initial Vaccination series and the initial booster dose, MLV and Recombinant Core vaccines will provide a sustained protective response lasting beyond 3 yr.”

Even now, long after research proved most vaccines last for life … the AAHA guidelines are still so tentative. What could be holding the AAHA back from making stronger statements or setting stronger enforcement policies?

Sponsor Influence

The answer may lie in their sponsors. In 2021 their sponsors are 3 major vaccine manufacturers: Boehringer Ingelheim USA Inc., Merck Animal Health, and Zoetis. And of course, the veterinary members of the task force also have a vested financial interest in more frequent vaccination.

Isn’t this a potential conflict of interest that could create bias in the task force recommendations?

It certainly looks like there’s been a lot of compromise. And the problem with compromise is that nobody really wins. Especially not dogs. 

Annual vaccination began without any scientific evidence to support it. And why is the AAHA now stuck at 3 years … when research shows DOI of at least 7 years for core vaccines? Dogs 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.

Proven Risks Of Vaccines

Every holistic vet recognizes the vaccine damage they see in dogs they treat. But this list isn’t just anecdotal … it’s from Dr Schultz’s research. Here is Dr Schultz’s 2007 list of adverse events from vaccines.

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

  • 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 that 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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What You Can Do

Holistic veterinarian Dr Patrician Jordan says:

“The truth is the majority of vets are not going to change until they are forced to – which isn’t 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. 

This change will have to come from the public, they have to stop allowing the over-servicing; they need to start filing lawsuits when their pets are manipulated and their purses are raided.”

So it’s up to us dog owners. Educate yourself on vaccination and start being a more active partner in your dog’s vaccine decisions. At the very least, question every vaccine that goes into your animal.

RELATED: Find out which vaccines your dog really needs …

Be your dog’s advocate – protect him with knowledge and by taking a stand against unnecessary vaccination. His life may depend on it! And share this article with other dog owners. Together we must push for change.


Schultz, RD. Duration of Immunity to Canine Vaccines: What We Know and What We Don’t Know, Proceedings – Canine Infectious Diseases: From Clinics to Molecular Pathogenesis. 1999:22.

Smith CA. Are we vaccinating too much? J Am Vet Med Assoc. 1995 Aug 15;207(4):421-5. 

Tizard I, Ni Y. Use of serologic testing to assess immune status of companion animals. J Am Vet Med Assoc. 1998 Jul 1;213(1):54-60. 

Schultz RD. Duration of immunity for canine and feline vaccines: A review. Veterinary Microbiology. 2006;117(1):75-9.

[Presentation to veterinarians ] Schultz RD. What everyone needs to know about canine and feline vaccination programs. 2008 Conference of the AHVMA. 2008.

[Article] Schultz RD. Dog vaccines may not be necessary. University of Wisconsin-Madison News. 2003 March 14.

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