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This Vaccine Can Impair Your Dog's Immune System

Dog owners in the Chicago area recently raised a red flag about harmful vaccine side effects when, within only 6 weeks, 5 dogs were diagnosed with life-threatening, brain-swelling autoimmune meningitis after receiving this vaccine. Is your dog at risk too?

vaccine adverse reaction


  • According to one Chicago area veterinary neurologist, "In the last year to year-and-a-half, we have seen more cases in this practice related to dogs who have recently been vaccinated”
  • Veterinary vaccine expert Dr. Ron Schultz questions the need for the number of vaccinations still being given to pets
  • The leptospirosis vaccine contains a powerful adjuvant that prompts a strong immune system response. It carries a significantly greater risk for adverse reactions than other types of vaccines

Editor's Note: This article is a reprint. It was originally published June 10, 2015.

Earlier this year, a local ABC affiliate in Chicago, ABC7 Eyewitness News, decided to investigate dog owner claims (no mention of how many) that vaccine side effects had caused harm to their pets.1

According to Julie Harding, owner of a 4-year-old Vizsla, her pet suddenly became violent and vicious, foamed at the mouth, thrashed about, and suffered unexplained seizures. The woman took her dog, Piper, to a veterinary neurologist who diagnosed her with autoimmune meningitis.

Meningitis is a life-threatening disease characterized by inflammation of the layers that protect the brain and spinal cord. In the autoimmune form of the disease, the body manufactures antibodies against its own tissues, producing a massive inflammatory response.

Piper Had Recently Received the Leptospirosis Vaccine

The veterinary neurologist asked Harding if her dog had been vaccinated recently, and learned that indeed, Piper had just received the leptospirosis vaccine. The neurologist noted in Piper's paperwork that her brain swelling could have been triggered by the vaccine and her predisposition to allergic conditions.

According to the ABC7 reporters (who apparently contacted other veterinary specialists for their story), "Veterinary neurologists say it was unusual to receive Piper's case and four others possibly linked to one vaccine within a month-and-a-half."

Predictably, when the reporters contacted the vaccine manufacturer they were told that "Each suspected adverse reaction was thoroughly reviewed and no causal association between the vaccine and the Chicago cases was found."

So if I understand this correctly … within 6 weeks' time, 5 dogs in the Chicago area who received a recent vaccination against leptospirosis were taken to veterinary neurologists suffering symptoms consistent with autoimmune meningitis … and the vaccine manufacturer would have us believe there is "no causal association."

Let's just say I'm not convinced. And apparently neither is Dr. Michael Podell, a Chicago-area veterinary neurologist and neurosurgeon, who told ABC7, "In the last year to year-and-a-half, we have seen more cases in this practice related to dogs who have recently been vaccinated. We are trying to understand what the risks are."

Number of Vaccines Disappoints Leading Experts

The ABC7 reporters also consulted my friend Dr. Ronald Schultz, a world-renowned expert in the field of veterinary vaccines and an immunologist at the School of Veterinary Medicine at the University of Wisconsin. Dr. Schultz is currently heading up the Rabies Challenge Fund to determine the duration of immunity conveyed by rabies vaccines.

Dr. Schultz told ABC7 he questions the need to vaccinate so often. "It's very disappointing to me to still have distemper, parvo, and adno [adenovirus] given every year when we know it provides a life of immunity," he said.

This is especially true since the latest canine vaccination guidelines, updated four years ago, call for extending the time between core vaccines from one year to three years, while also acknowledging that immunity lasts at least 5 years for distemper and parvo, and at least 7 years for adenovirus. This is essentially an admission that even the new 3-year interval guideline is overkill.

Unfortunately, two full years after the new guidelines were published, over half of veterinarians were still doing unnecessary, potentially dangerous annual re-vaccinations. As Dr. Schultz explained to ABC7, vaccinating an already-immune animal may cause a hypersensitivity reaction.

Holistic Vet’s Only Administer Rabes Vaccines After One Year

ABC7 also talked with my good friend Dr. Barbara Royal, who owns the Royal Treatment Veterinary Center in Chicago.

Dr. Royal, like most holistic veterinarians, opts to use antibody titer tests to measure a pet's immunity vs. automatic vaccinations. She says that aside from the required-by-law rabies vaccine, many of her patients no longer receive vaccinations past their puppy/kitten shots and boosters at one year. She believes those animals are now healthier.

"Someone makes a vaccine and we all have to give it, but the efficacy and the safety of those vaccines is not necessarily that well researched," Dr. Royal said.

During their investigation, the ABC7 reporters discovered that if a dog has an adverse reaction to a vaccine, veterinarians are not required to report it to the manufacturer or the government, although many do.

The All-or-Nothing Vaccine Trap

ABC7 also received a statement from the American Veterinary Medical Association for their story:

"While adverse reactions can occur, they are extremely rare, and the benefits far outweigh the risks. Vaccination is the primary reason why deadly diseases like rabies, distemper, parvovirus, and panleukopenia have become much less common in US pets. Pet owners should talk with their veterinarians about any concerns they have regarding vaccines, and to determine the best vaccination plan for each individual pet."

This statement reflects an all-or-nothing trap many people who should know better seem to fall into.

Those of us who refuse to give unnecessary vaccines understand the value of core vaccines for puppies and kittens. We aren't advocating a "do nothing and hope for the best" approach. We are advocates of giving the absolute minimum number of vaccines to protect young animals from life-threatening illness, and treating each animal as an individual in assessing what vaccines he or she needs, and how often, throughout their lives. In most cases, revaccination of adult animals is rarely indicated.

In my personal experience, adverse vaccine reactions aren't all that rare. Julie Harding, loving owner of a 4-year-old dog who now has autoimmune meningitis, probably doesn't think so either.

Additional Information About the Leptospirosis Vaccine

The leptospirosis vaccine is a bacterin — a vaccine made from killed bacteria, which in and of itself won't prompt an immune response to make antibodies, so a powerful adjuvant (usually a heavy metal such as aluminum or mercury, aka thimerosal) is added that elicits a strong immune system response. Because of this, it also carries a significantly greater risk for adverse reactions.

I feel that because my profession is testing for leptospirosis — an ancient endemic infection — more frequently, we're finding more positive animals. As a result, we're fostering a tremendous amount of fear and anxiety in pet owners over a bacterium that is far from a "new risk" for dogs. In fact, it's been in the environment since the beginning of time.

Unfortunately, many vets are still promoting repeated vaccinations for all pets, despite the significant risks associated with unnecessary revaccination. Further, a lepto infection is entirely treatable. So, my question is, why vaccinate for something that's one hundred percent treatable? I've handled about a dozen cases of lepto in my career and have never had a dog experience any lingering problems from the infection. I recommend you skip the leptospirosis vaccine.

If you live in a lepto-endemic area, make sure your dog's immune system is strong, and you can certainly go the extra mile by taking precautions to insure your pet doesn't have an opportunity to be exposed to the leptospirosis bacteria.

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