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Hot Debate: Vaccine Causing Tumors in Dogs? – How High’s the Risk?

There has been a lot of talk lately about over-vaccinating and the potential side-effects of vaccines, including cancer. But how high are these risks in dogs? Is it really worth risking your dog getting the disease by not vaccinating?

The Pro Vaccine Camp

Dr. Susy Horowitz of the Pasadena Humane Society & SPCA defends why vaccines are still important and something every dog owner should make sure their best friends are getting.

Why are the vaccines important?

Vaccinations are an essential component of a wellness program for your dog.

For example, Distemper and Parvovirus were both prevalent diseases in the past making dogs very sick with an associated high risk of death.  In addition, many dogs that survived Distemper developed health problems a few weeks to a few years later (some of which were severe enough to require euthanasia).

Rabies is an always fatal disease which can be transmitted to people (and is almost-always fatal in humans as well).  In some jurisdictions an unvaccinated dog bitten by a wild animal may be required to be euthanized.

What can they do that natural remedies/natural “supplements” etc can’t?

Vaccinations consist of either de-activated viruses or bacteria or partial viruses (called components) that are still able to stimulate an immune response against the disease without causing the disease itself.  Products that claim to stimulate the immune system cannot confer immunity against a specific disease and are not considered protective for specific diseases

What are the risks to dog’s with vaccines?

In rare cases, dogs can have reactions to vaccines. Image source:
In rare cases, dogs can have reactions to vaccines. Image source:

Vaccinations rarely cause harm to an individual although specific allergic reactions may occur in a very small percentage of those receiving a vaccination.  Most vaccination reactions are mild (lethargy, short term discomfort at the vaccination site or other mild symptoms).

In the future an anti-histamine or anti-inflammatory may be given prior to or at the time of the vaccination to prevent or decrease a reaction. There are very rare occasions where a pet’s medical condition will make vaccinating inadvisable. Your veterinarian will make that determination if your dog is diagnosed with one of those rare conditions.

How likely is that a dog will get a tumor (or other reaction) from a vaccine?

In a very small percentage of cats tumors have been linked to an injection site (any injection, not just a vaccination, although these tumors were first observed in parts of the body where vaccinations are commonly given).  There has not currently been shown to be a link in dogs between injection sites and vaccinations.  Veterinarians concur that the importance of protecting against disease in most cases outweighs the risk of the vaccination.

 The Con Vaccine Camp

Dr. Judy Morgan, owner of Clayton Veterinary Associates and Churchtown Veterinary Associates in New Jersey, explains the danger of vaccines. She is a graduate of the University of Illinois College of Veterinary Medicine and more recently, the Chi Institute of Veterinary Traditional Chinese Medicine and Acupuncture.

What is the worry about pets being over-vaccinated?

Every time a vaccine is given, the pet’s immune system must respond to that vaccine. It’s not automatic immunity. The immune system can be stressed and go into overdrive, attacking the body’s own cells, or it can stop functioning and stop protecting the animal, depending on which way it decides to head. Over-stimulation of the immune system can lead to chronic inflammatory diseases like Inflammatory Bowel Disease, arthritis, diabetes mellitus, chronic allergic dermatitis, autoimmune thyroiditis, autoimmune hemolytic anemia, and cancers.

How likely are dogs to get a tumor (Or other reaction) from a vaccine?

Allergic reactions are being seen more commonly, especially since animals are being given so many vaccines at one time. Some animals come into my office with a crashed immune system after being given vaccines containing 12 antigens at the same time.

Cats are more likely to develop fibro sarcomas after being vaccinated, but they can occur in dogs as well. Some tumors that occur in common injection site areas have not been linked yet with vaccination, but I’m not sure how hard any scientists are trying to make that link either.

How can holistic practices keep dogs healthy or protect them from diseases?

We use titers for distemper and parvovirus to determine whether a pet actually needs a vaccine.

We use ultra-low dose vaccines which have less damaging preservatives present in them.

We talk in-depth with every client about the exposure there dog or cat really has to each disease, rather than pushing owners to vaccinate for everything available.

We also work much harder to ensure the animals are fed a species-appropriate diet and that their immune system is kept in tip-top shape, whether that be with added vitamins and herbals, or diet therapy.

As an example, do you believe dogs should get the bordatella vaccine every six months? Why or why not?

I do not believe they should get this vaccine ever. They can shed the disease after vaccination and expose other animals to the disease. The vaccine is short-lived and only vaccinates for a few of the upper respiratory illnesses that can affect pets in high density situations. Kennel cough is not life-threatening. It is annoying.

There are over 60 respiratory illnesses that pets can be exposed to; vaccinating for 3 makes no sense.

Do you think there are any vaccines that are not necessary at all?

Bordetella. I use Lyme extremely sparingly. There are a dozen tick-borne diseases, so vaccinating for one of them seems silly to me. The important thing is keeping the ticks off and monitoring for signs of Lyme disease. It is a treatable disease when caught early. Leptospirosis is an extremely reactive vaccine, particularly in small breeds of dogs. We always have a long conversation about exposure possibilities. Again, this is a treatable disease, if diagnosed early. I have seen 2 cases in 30 years, so I think it is a little over-hyped, but it is more prevalent in some locations. I would never use the Giardia, Porphyromonas, or Coronavirus vaccines.

It is said that vaccines can last longer than traditional vets say? Why do they tell us to re-vaccinate?

Distemper and parvovirus vaccinations can last for 5 to 8 years, possibly lifetime. The new 3-year DAPP is actually guaranteed for 5 years, but labeled for 3. Rabies vaccines may last much longer, but because Rabies is zoonotic and not treatable, we err on the side of caution. The Rabies Challenge Study has been ongoing and will hopefully change the duration of the vaccination labelling. Adenovirus (hepatitis) also probably lasts for the lifetime of the pet. We were all taught in school to vaccinate every year. No one really knew the duration of immunity and no one thought there were any side effects to vaccinating every year. Now we know better, but old school veterinarians are hard to win over. Plus, for decades we have linked the annual physical examination to the vaccinations and veterinarians are afraid if they downplay the need for vaccinations pet owners will not bring the pets in for the annual exam

The Bottom Line

You need to discuss your dog’s health with your veterinarian (or two, as second opinions are always good!) to make sure your decision is based on what’s best for your dog and not on others personal beliefs.

About the Author

Based in Wilsonville, Ore., animal lover Kristina N. Lotz is a Certified Professional Dog Trainer – Knowledge Assessed (CPDT-KA) and works as a full time trainer. She is the founder of A Fairytail House, a unique all-positive all-sport dog training facility that helps rescue dogs in her area and provides free seminars and training classes for the community. In her spare time, she trains and competes in herding, agility, obedience, rally, and conformation with her Shetland Sheepdogs. She smartly married a Veterinary Technician, who helps keep the fur kids happy and healthy, and provides a quick resource for articles.


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Written by Kristina Lotz
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