Can Vaccines Cause Cancer in Dogs?

The evidence says no (beyond the rare injection-site sarcoma). But I'm willing to engage in debate.


I recently received a question from a fellow Dogster writer:

Hi Eric,

More than a few commenters on my cancer story are claiming vaccines cause cancer. It would be great if you could weigh in with your professional opinion.



The timing of this qustion could not have been more apt, because I had just finished writing an article for Catster on injection-site sarcomas (formerly known as vaccination-associated sarcomas) in cats. The link between vaccines (and other injections) and cat cancers is well-known and well-proven. In dogs, the matter is much muddier.

A recent paper in the Journal of the American Veterinary Medical Association stated that vaccines have been linked to injection-site sarcomas in dogs. These tumors appear to be dramatically rarer in dogs than in cats (and they’re already quite rare in cats), but they have been reported. To put things in perspective, I’ve never seen one, and I’ve never met a vet who has.

But do vaccines cause other types of cancers in dogs? I have heard some vets posit that today’s seemingly increased rates of cancers such as lymphoma may be linked to over-vaccination. And I have heard, ad nauseum, plenty of screaming anti-vaccination fanatics claim that vaccines cause all manner of harm in all kinds of species. In these types of situations, I always invoke the modified Jerry Maguire rule: Show me the study!

And that’s where the claims linking vaccines to cancer (other than extremely rare injection-site sarcomas) fall short. I have searched veterinary databases repeatedly — I did a search just today — and have yet to find a study that links canine vaccinations to other types of cancers. If any person reading this can site such a study, I’d be very interested to read it. Note that I’m not interested in reading anti-vaccine propaganda. I’m interested in controlled, well-run scientific studies.

It is noteworthy that when one searches veterinary databases for studies on vaccines and cancer, many results do appear. But they do not describe studies showing that vaccines cause cancer in dogs. Rather, they are papers reporting on the use of vaccines to treat cancer.

Vaccines are designed to stimulate the immune system, and it turns out that the immune system can be activated to fight cancer in the body with special vaccines. A vaccine for treating certain canine melanomas is already available. Researchers also are exploring vaccines to treat lymphoma, mammary tumors, and soft tissue sarcomas.

This article should not be construed as advocacy for an every-shot-for-every-dog-every-year policy. Quite the contrary. Whether or not over-vaccination causes harm, administering unnecessary vaccines to dogs does them no good. The truth is that nobody knows how often dogs should be vaccinated. Each dog’s needs are unique. Some people advocate using blood tests known as titers to determine whether dogs need to be vaccinated. Titers do provide useful information, but they only measure half of the immune system (they measure humoral immunity, but ignore cell-mediated immunity).

Most well-respected veterinary institutions now generally recommend triennial vaccination for most dogs. For older dogs, I think that might be overkill. My pal Buster most recently had vaccines two-and-a-half years ago. He’ll definitely get his rabies vaccine when it’s due in six months, since it’s required by law. But, at eight years old, I’m not sure I’ll be giving him any others for a while longer.

Further research on vaccination protocols is highly warranted. An honest, well-informed public discussion about vaccines is a very good thing. And people shouldn’t lose perspective: Unvaccinated dogs die from parvo every day. There is no question that, on the whole, vaccines save lives. Every puppy should benefit from a full set of vaccines. Every pet owner should talk with their vet every year about which vaccines, if any, might be appropriate.

Unfortunately, well-informed public discussions about vaccines are very difficult to have. The discussions often are hijacked by anti-vaccination fanatics. These folks seem to believe that vaccines are the cause of all the world’s problems. They spend an awful lot of time on the Internet, and they love to comment on articles like this one. They tend to grasp onto any evidence (no matter how spurious) that vaccines might be dangerous, and they are fond of linking to propagandist websites that promote their cause. In my opinion, they don’t contribute anything useful to the conversation.

Don’t get me wrong. I want to listen to people who have had bad experiences with vaccines. I want to evaluate any solid evidence put forth in favor of or against vaccines. But I don’t want to hear propaganda.

If you feel that you have something productive to add to an honest, well-informed public discussion about canine vaccination, please dive into the comments section.

Or, you can take this poll: Readers, have you ever had a bad experience with dogs and vaccines?

26 thoughts on “Can Vaccines Cause Cancer in Dogs?”

  1. The sheer number of anecdotal accounts here (and elsewhere) of previously healthy dogs developing fatal cancer after rabies vaccinations is itself evidence that ought to be taken seriously by the author — and the veterinary establishment as a whole. Since Covid, much has come to light about the way that pharmaceutical companies distorted scientific research into the effects of vaccinations to suit their bottom line. It's hard not to suspect a similar dynamic here. With almost every dog in America required by law to get the shot every few years, it's a cash cow for the industry that creates a powerful commercial disincentive to fund the requisite research. Unfortunately, the medical establishment has lost credibility with much of the public in recent years due to its unholy ties with the political and economic power structure, and so appeals to science that do not take into account this potential for institutional corruption don't settle the matter in the way they used to.

    Those who question the safety of vaccines are typically dismissed by the medical establishment as fanatical and irrational. Yet it's hard to overstate the degree of helplessness and rage that a person feels when their beloved healthy dog gets sick and dies in apparent causal connection to a state-mandated vaccine, and there is no one in the system who will listen. There's just nowhere to go with the feelings of violation.

    I myself don't even know what to do with the outrage I feel about my own situation with my dog Jackson. He was an extremely healthy and happy 12 year old Bichon Frise, living a care-free life involving daily runs at the beach, plenty of love, and a healthy organic diet. We got him his rabies booster without even thinking about it. The day after the shot, he was sicker than we'd ever known him to be, curling up within and not eating for three days. A couple of weeks later he developed a cough that wouldn't go away. We thought it was a cold at first. When we finally took him to get checked out, X-rays showed one half of his lungs already covered in cancer. Six agonizing months later we said goodbye.

    Of course, the vets we worked with — though fine and capable professionals — declared it impossible for the vaccine to be a cause. Yet a simple Internet search reveals that many vets believe there is a connection. See, e.g.,

    And how could we not suspect a link? One day he's the picture of health, living an entirely stress-free, happy, and natural life. He gets the vaccine. He immediately gets sick. It's cancer. He dies. It's a pretty strained argument to suggest this was just coincidence. And when you encounter story after story of similar tales from other dog owners — as in this thread — it infuriatingly confirms your suspicions.

    I understand that rabies is itself a genuine public health problem. Perhaps it even is the right policy, on balance, to mandate regular rabies vaccinations (I'm not sure I believe that, but let's just say that's true). What feels clearly wrong though is not to be made aware at the time of the vaccination that there ARE risks. Had we been alerted to those possibilities by the vet when Jackson was vaccinated, we would have intervened immediately at the first signs of illness. I'm sure we would have saved him.

  2. My German shepherd was diagnosed with lymphoma 9 months ago. I tried the Joe Tibbens remedy and I thought it was working but his days came to an end a week ago. My mini aussie, who was seemingly perfectly healthy leading up to this point, grew extremely ill within that following week of putting down my German shepherd. I thought it was grief, but found out he was full of cancer (lymphoma) and had to be put to sleep too. Within one week. They were both 8. The last time they were vaccinated was 14 months ago, but I completely attribute it to those vaccines. What else could cause lymphoma in two different dogs to die at the same time? Anyone that can answer that question????? And finding any scientific lab to do a study? Laughable in this age of money grubbing sociopaths. They won’t even admit what they’ve done to humans much less animals.

  3. I am seriously wondering if there is a correlation. Our 8 year old Westiepoo was totally healthy for her entire life. We only gave her puppy shots and never did any boosters after that. Then there was a Parvo outbreak in our area so we decided to get the DHPP booster 4 months ago. (No Rabies vaccine as she was an indoor dog) A month later her personality started changing. Not as happy. She went downhill from there. Balance issues about a month ago. Then the last 2 weeks it got much worse. Her vision started going. We took her to the Vet 3 times. Finally lymph glands, in her neck, were huge this past week and sure enough it was Lymphoma. Worst day was putting our Sweet Girl down. I thought it was strange that after the vaccination booster her health changed so rapidly. Reading other pet owner comments I wish we had never given it to her. As a kid my dogs lived much older. The only difference was we never gave them boosters.

  4. My short unscientific experience. As a child we were on a very limited income, but we were able to have pet dogs. We just couldn’t afford shots or visits to the vets. Those pets lived well into old age. As an adult, now in mid fifties, we always kept up with shots and vet visits. We’ve spent the money for an amputation and cancer treatments for both a cat and a dog. Currently we are waiting to see another oncologist, after having a cancerous spleen removed. The only difference through the years is the ability to afford per care. I’m not an antivaxer, but I am leaning to the coincidence that most of my well cared for pets, have developed cancer.


  5. Of course this author can say "show me the studies" who would do the studies? I had two rescued dogs one right after the other develop cancer and I fed organic food made myself. I gave them every vaccine I thought they needed. When I was young, we couldn't afford to give our pets vaccines every year, so they never got them. Those dogs and cats lived to be very old and never died of cancer. Something is causing all this cancer in dogs. I just got a puppy from the Humane Society. She already had the standard vaccines so now I will do titers when it is time for the next vaccination schedule. The author has failed to show studies that vaccines do not cause cancer so the pendulum swings both ways.

  6. It’s unfortunate, and rather ironic, that Eric’s doesn’t meet the same standards for objectivity, neutrality, and rational debate, that he trumpets in his article. Calling people who question the safety of vaccines “screaming fanatics” who engage in “propaganda” is not exactly an unbiased unemotional approach to the debate. Physician, heal thyself.

  7. I found myself here after realizing it would be difficult to gather hard information on the dangers of the rabies vaccine. We had a German Shorthaired Pointer, he was 15 years old. My husband had him since Oscar was just a pup. Oscar had a problem with jumping the fence and running off at the sight of anything moving. We did absolutely everything possible to keep him happy and where he belonged per the law. He master minded his way out of our yard one last time 2 months ago, we thought he was too old but he proved us wrong! Dog snatcher got him that day, and I had to go to court and prove that I had gotten him a fresh rabies shot. I knew in my heart it was wrong, I tried to find a vet to give him an exemption. None would. I got him the shot when I should have advocated for him as hard as I possibly could. Less than 8 weeks later we took him 2 hours away to the emergency 24 hour vet, he had to be put to sleep. He was full of lymphoma. I will never forgive myself for not sticking up for him, for not simply telling the courts no. They killed him with that shot. They killed him…

    1. Hi, I am edward, I had my little dog to the vet, about 2 months ago, I wanted to have her exzaming, for intestinal worms, the doctor, who tried to insert the monitor inside of my dog, couldn't even insert it. She takes my little dog back in the back some place and later comes back saying they did blood work on my dog, of course my poodle she's 16 year's old…which seems to be in fairly good health at that time… although she have had some problems with her liver, after she was spaded, and now after the visit two months ago now we are dealing with a tumor, on the back right side of her leg, she had never had any kind of problem with tumors, until that vet visit, I began to see her beginning to have a hard time walking properly, there's this big tumor, on the inside of her back hind right leg, now my little dog is too old for any kind of surgery and so on .she was fine until that vet visit, I'm heart broken over this, I think any one who aminters vaccination, should be properly trained and know how to give them to dog's…we love our pet's that why we take them to the vet, we pay good mounts of money, to pretect our little dog's from harm… I've got to say I am outraged over this now I'm losing my baby…has anyone got any ideal what I can do to help save my baby.

  8. My 6 year old Standard Poodle was in great health. Full round of routine vaccinations – excluding rabies which was not due – and a clean bill of health. 1 week later he developes a "raging" urinary tract infection and is started on antibiotics. 1 week later he is diagnosed with hypercalcemia and large cell lymphoma. 4 days at the emergency vet hospital and his prognosis is poor. Started a regimen of prednisone and antibiotic. 2 months later he is gone. I was told lymphoma is common in Standard Poodles. Too much coincidence for me. Groomers, doggie day cares and boarding facilities all require proof of complete vaccination so there is really no freedom of choice.

  9. We have an older Jack Russell, who had to have 10 teeth removed. She had had a full blood work up. No lymphoma. And they wanted all of her vaccines done before they would pull her teeth. So now four weeks later she’s full of lymphoma and on the verge of death.

  10. Add me to the list of TWO dogs and one cat who died shortly after receiving their rabies vaccine.

    The rabies vaccine in my state is required by law. Just because something is law doesn’t mean it’s logical or for the right reasons.

    Going forward I will NOT be vaccinating my pets for ANYTHING. You humans are a disgrace. I’m sure you’re sleeping comfortably profiting off sick pets and no remorse. Fire yourselves. Or better, set yourselves on fire.

  11. Just starting to look into this, I had an amazingly strong athletic 10yr old dog, had his first jags as a pup 10 yr ago, never recieved any boosters untill age of 8, which started to cause slight digestive problems, urine infections, then one at 9, along with being chipped. He still looked 12month, bouncing around like a pup up untill the end. His MCT started to grow and fast at the vaccination point on his kneck also the same location of the foreign body of the chip. It was so aggressive he was put to sleep 10 days after diagnosis, it was extremly aggressive and had already spread causing many more tumours and through the lymph nodes. Only left wondering if he still be here if he never got them boosters started 2yr ago.

  12. What hogwash this article is. What an egotistical person this guy is. Science is clearly your religion, which is comical because science is based on theories.

    Anywho, I have a paper trail to prove that the rabies vaccine caused my dogs cancer. 3 vets acknowledge it, and a 4th as an ER vet also acknowledges it. For you to be so close minded, you really need to get out of the medical field. It takes one with an open mind and excellent critical thinking to acknowledge that NOTHING is one size fits all. That not all animals have the same genetics, and like humans have mutations that might be triggered (epigenetics) when given a vaccine. These mutations that could be triggered could be cancer causing. It’s a shame Pamela has you come on to answer this question.


    Pro informed choice advocate

  13. Why would you find information that goes against the governments push on something? Did it not seem obvious to you when doctors and people were posting actual information, proof and pictures, And then they delete removed for “medical misinformation” that something fishy was up???? that when a notice was released Saying no one is allowed to post anything that goes against vaccination, might seem fishy to you!? Why would our largest multi billion dollar corporation who runs our CDC department, major banks, politicians, writes our doctors books and makes our baby formula WOULD EVER TELL YOU WHAT THEY ARE SELLING IS A PROBLEM??????!!! I can’t believe someone as smart as you literally goes by the PROVE IT method SMH!!!!! A lot of us can prove it and a lot of us have children who died or got encephalitis within 2 hours of them getting their shots but they keep removing our proof and stories as medical misinformation and threatening us with law suits or shutting our accounts down. The internet is highly guarded. By those who create the problems and sell the solutions that create more problems that bring in more money. They were sued for over 15 billion and it never reached the news. Did you know out of the 3 entities that own our news channels, two of them actually fund the CDC and own over 16 patents for our vaccinations? The list goes on.

  14. So answer me this: Exactly WHAT company is going to front the major $$$$ to fund a study proving a link between vaccines and cancer? Who? Nobody that’s who because then no one would vaccinate and there goes all the profits to the vets and pharmaceutical companies! A simple read of the ingredients in vaccines shows the harm being injected into our pets over and over again.

  15. Neil SignorelliOP

    All of our dogs receive regular vet attention. We have had 6 of 7 die from cancer. More research needs to be done. All of our dogs and cats have been rescued. I seldom bring our cats to the vet and they all seem to be ageless after many years. Perhaps there is merit to not injecting dogs so often.

  16. My Boston Terrier got a injection site sarcoma. The blue die from the rabies vaccine was in the center of the tumor!!! Vets don’t care, this is big bucks for them every year or 3!!! The rabies vaccine company right away offered $500.00 towards his medical care, no questions asked. I am thinking about suing them for willful harm.

  17. I had my perfectly healthy Beagle / Terrier mix vaccinated for rabies, Bordetella and DHPAP. 90 days after the injection the same leg became swollen 5 times the size of normal. She also had extreme digestive problems and required immediate vet care. The swelling subsided for a short while but then returned. She then developed 2 large tumors that came thru the skin. After 60 days her blood count had dropped to 1/3 normal. Apparently she had extremely aggressive cancer and we had to end her suffering. Coincidence? I had a bad gut feeling when the vaccination was being administered and should have followed my instinct.

    1. I took my 8 year old perfectly healthy dog inn for a Parvo vaccination due to a news item that scared everybody. My baby was dead, full of tumors, within weeks. The Vets made a grand total of $7k from us and nobody bothered telling me she didn’t even need a shot at 8.

      I then did my own research, which is not propaganda but mostly ages with what ypthe written above, but there s plenty of known research now that shows they have been including cat DNA in dog vaccines etc. And treats ago the experts understood that injecting direct into to dog of foreign matter is making the matter kill the now foreign host.

      I’m surprised ypthe not come across that very important research yet. Try looking at what Australian professionals have to say before calling anything you haven’t read yet, propaganda. I’ll take you to the links, I’ll have Thai discussion right here – in fact, let’s compare notes. I’ll give your everything you’re missing ? Propaganda indeed!! Anti Vaxxers are full of researched knowledge from their own experiences. Wake up!!

  18. My wee Jack Russell and my beloved Rottweiler both died from cancer at the site they were given the rabies vaccine. They had never had boosters their whole lives and they lived in the country and were fed a predominantly organic diet. Within 3 years of having the rabies vaccine (needed to take them abroad) they both had cancer at site of injection. Obviously, I’m absolutely furious at myself for having this poison put into their bodies but more so, sad and sorry to my wee boys for cutting their lives short. I hope anybody reading this will never inject their dogs with any poison (even if your vet tells you they need it).

    1. If I knew. You realise I'm here reading trying to understand in tiers my much beloved dog died of limphoma cancer diagnosed two months after receiving the antirabic vaccine. To travel abroad.A very healthy dog, with realy good blood test not long ago.

  19. Does Dogs Have Souls? Pets or animals have souls–and so do plant life. Will this answer appear to be something from the New Age motion? Don’t worry–it isn’t. Be confident we’re not expressing animals and plant life have souls like ours.

    The spirit is the basic principle of life. Since pets and plants you live things, they have got souls, however in the sense where humans have souls. Our souls are rational–theirs aren’t–and ours are logical because they’re religious, not material.

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