Evidence Update: Vaccination and Autoimmune Disease

One of the potential adverse effects of vaccination is the triggering of autoimmune diseases in susceptible individuals. There is some evidence in humans, for example, that the routine MMR vaccine (which prevents measles, mumps, and rubella) can trigger an autoimmine disease, called ITP, which destroys platelets and reduces a patient’s ability to form normal blood clots. The evidence suggests this occurs in roughly 1-3 children for every 100,000 MMR vaccinations.

While this is a real and serious risk, it is important to note that not only are the diseases prevented by this vaccine a much greater risk, but it turns out that these disease can also cause ITP and at a much higher rate than the vaccine (1 child out of every 3,000-6,000 cases). Therefore, the benefit of vaccination is clearly greater than the risk in this case.

There is, as always, far less data to determine what, if any, risk of autoimmune disease there is in vaccination of dogs and cats. Both ITP and IMHA, another autoimmune disease involving destruction of red blood cells, occur in dogs, and these have been reported to follow vaccination. However, the relevant research literature is sparse, flawed, and inconsistent. The bottom line from my previous review of the literature was this:

Bottom Line

  • Little evidence vaccination causes IMHA/ITP
  • No consistent temporal association
  • Data are weak
  • Overwhelming majority of vaccinated animals do not develop these diseases
  • Infection can be a greater risk for IMHA/ITP than vaccination
  • Don’t vaccinate more than necessary
  • Don’t vaccinate less than necessary
  • Don’t avoid vaccination out of fear of IMHA/ITP

A small piece of additional evidence was recently presented at the American College of Veterinary Internal Medicine (ACVIM) 2017 Forum.

Moon, AKB. Veir, J. Vaccination Behavior and Adverse Events in Dogs Treated for Primary Immune-Mediated Hemolytic Anemia (Abstract HM17) ACVIM Forum, National Harbor, MD, 2017.

This study surveyed the owners and veterinarians of dogs who had been diagnosed with IMHA. Such dogs are frequently not vaccinated once they recover from the disease because of concerns that vaccination might trigger a relapse. This is often done even when there is no specific reason to think vaccination triggered the initial episode. It is a reasonable precaution, but since it is not clear that vaccination actually is a risk factor for ITP or IMHA, it is possible that these dogs are being left vulnerable to infectious diseases unnecessarily.

In this small study, survey results were available for 44 dogs. There were several relevant findings:

  1. The average time from most recent vaccination to the initial onset of IMHA was 351 days. Such a long period makes it unlikely that vaccination was a major trigger for IMHA in many of these dogs. It still might have been in the subset who were vaccinated closer in time to the onset of their illness. This study found no such temporal relationship, but a different study design would be necesary to confirm that.Previous studies have found only a small proportion of IMHA cases received vaccinations in the 2-4 weeks before the onset of their illness, and most found no difference in recent vaccination rates between dogs who developed these diseases and comparison dogs who did not. So far, the overall data suggests that vaccination is rarely a proximal trigger for these autoimmune disease, though whether they play a role as an overall risk factor isn’t known.
  2. About half of the dogs had not been vaccinated since their IMHA diagnosis. This is consistent with the common practice of many vets to eschew vaccination in dogs who have had a history of autoimmune disease. However, about half of these dogs did receive vaccines after their diagnosis, and almost all of these were rabies vaccines. This is likely because rabies vaccination is legally required in most of the U.S. and exceptions are not always allowed for dogs with a history of autoimmune disease.Only 2 of the 21 dogs who were vaccinated following their IMHA had any reported adverse reaction. These two reactions were typical of the acute hypersensitivity reaction seen with vaccination. No relapse of IMHA or other autoimmune disease was reported in the vaccinated dogs. This suggests that such dogs may not be more sensitive to vaccination than other dogs, though again the size and methodology of this study is not adequate to demonstrate that with any certainty.
  3. Though this is just a small bit of data, it does fit into the larger context of existing evidence in dogs, and the much more comprehensive evidence in humans, suggesting that vaccines play an extremely small role, if any, in triggering such autoimmune diseases, While caution is warranted, and certainly unnecessary vaccination should be avoided on principle, there is no justification for extreme and confident claims that vaccines are a major cause of these autoimmune diseases in our pets or that what risk may exist outweighs the benefits of appropriate vaccination.
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19 Responses to Evidence Update: Vaccination and Autoimmune Disease

  1. DogsMum says:

    You may sound knowledgeable and I admire the fact that you do refer to scientific evidence for every article. However. I lost my dog to IMHA as a result of vaccination, L4 containing thiomersal to be precise. Until that moment my boy was healthy and never required any medical attention or help.

    Since then I have also met at least 30 dog owners who lost their dogs to IMHA as a result of L4 vaccine. I have then switched the vet and now work with the one who spent several years studying IMHA with particular interest in the link between vaccinations and the condition (as well as other side-effects)

    They DO NOT use L4 vaccine in their practice because since it was introduced by other surgeries, the number of dogs dying from IMHA increased from 1-2 per year to at least a dozen! True, there is no firm evidence between the disease and specific ingredient, but one has to be blind and brain-washed NOT to see the link.

    I do still advocate vaccinations because I am not from the dark ages and do understand the importance of immunisation, but I would strongly disagree with the fact that vaccine is not linked to IMHA as well as several other fatal conditions.

  2. skeptvet says:

    I understand why your experience leads you to this conclusion. The problem is that when others have entirely different experiences if there is no controlled data you end up with clashing anecdotes and everyone simply chooses to believe their own and ignore everyone else’s. That vaccine has been widely used, and we certainly use it often at my hospital. We’ve seen no change in the occurrence of IMHA and have not had any dogs develop IMHA associated with receiving this vaccine. Likewise, since the vaccine was introduced, there is no evidence of any increase in the incidence of IMHA. And if you think the thiomersal is responsible, why has this association not been seen in humans, when that preservative was widely used for many years, or with all the other vaccines containing the same ingredient? Again, all you have is anecdotes and opinions, and while the conclusion you’ve drawn is reasonable based on these anecdotes, it is not consistent with the experiences of many others. Either we then give up on determining the truth and just all believe our own stories, or we rely on controlled research data rather than anecdotes.

  3. As another evidence-inspired practitioner, I am grateful for the time and effort Skeptvet puts forth in this continuing discussion. An anecdote, if you’ll allow. A mid-career small fluffy dog with known history of immune-mediated thrombocytopenia (low blood platelets, leading to bruising/bleeding) arrived for a rabies booster. Young couple owners, very nervous about boostering a dog with an immune mediated disease. We’re in PA and have a rabies vaccine law. The law, though, allows us to make a medical decision not to vaccinate, if the attending vet thinks it might be risky. I thought it was risky, to the relief of the owners, completed the exam, signed a rabies waiver (which is sent to our Dept. of Ag.), and off they went. 10 days later, bruising, petechia–platelets too low to count on CBC. This from not vaccinating a little fluffy dog. I cheekily offer this anecdote as proof that not vaccinating for rabies can lead to ITP. I did tell the owners how glad I was to not vaccinate, as this case would have left us all indelibly persuaded that the episode was vaccine-related, when it was very clearly not. I remain not inclined to booster this dog, he remains “lapsed” on his rabies in the eyes of the law.

  4. Val says:

    I recently adopted a 10-year-old dog who had never been vaccinated. Before I could get her her shots, she was diagnosed with SLO and my vet didn’t want to vaccinate her. I don’t know if I should second-guess this decision or not.

  5. skeptvet says:

    If the dogs has truly never been vaccinated, then there is some significant risk from several infectious diseases, and vaccination makes sense. That said, it is very rare to see a dog that age who has never had vaccines, and often they have them as puppies and the records aren’t there. You could get titers checked which would at least indicate past vaccination if positive.

  6. Joan Cumisky says:

    I adopted a dog and found she has ITP and cardiac disease. She is on 20 mg Doxycycline and 5 mg of Enalapril. Is it safe for her to get a rabies vaccine?

  7. skeptvet says:

    As you can see from this article, there is no simple right answer. There is some evidence vaccination might be a risk factor for ITP, but it is weak and inconsistent. Rabies risk is also probably pretty low for most dogs who have been properly vaccinated in the past, but it is generally legally required. I often recommend asking the relevant authority for a medical exemption from rabies vaccination for dogs with a history of autoimmune disease as a precaution, unless there is some clear reason to think they may be at risk (dogs who regularly encounter wildlife that can carry rabies, such as raccoons, skunks, bats, or others depending on your area). However, I have also seen dogs with a history of ITP who subsequently received rabies vaccination with no recurrence or other ill effects. So while I think it is reasonable to avoid the vaccine if you can, there is not strong evidence to support claims that it would be harmful.

  8. Deborah Cottrell says:

    We’ve been using the L4 for several years, and I can still count on one hand the number of cases of AIHA. The incidence has not changed, and we’re talking about several thousand doses. If Dog’s Mum’s vet really thinks the data is there, he should certainly publish it. Why isn’t he doing that? Does he not want to help other dogs avoid AIHA? Or is it because the data is not really there?

  9. The Other Science Guy says:

    As a scientist I agree with and understand SkepVet.

    As someone who lost his healthy happy dog Spanky (Australian Shepherd mix) to IMHA in 2003 after an unnecessary vaccine as a requirement for boarding, I agree with DogsMum (except the thermiserol parts)

    I still vaccinate my dog GMO (female rat terrier mix). But I am careful to find a vet who agrees that the vaccine requirements for dogs might be a bit overzealoused and I never board her because of their vaccine mandates. For example, my dog is rarely around other dogs so I don’t vaccinate her against kennel cough. But we do live in the forest so definitely vaccinate against Lyme.

    SkepVet: My experience with IMHA happened in 2003 in your area of California. I would be glad to speak with you privately and give testimony of my account. And I will keep my scientist hat on when I do. However, I do have a tiny bit of resentment towards the staff of the facility in question but I don’t believe they are completely negligent. Spanky had been vaccinated many times before without incident so I believe he just got a bad batch of 6 in 1

  10. The Other Science Guy says:

    2 out of 21. That’s 30%

    Ok, let’s have a little fun.
    I think we can all agree, having unprotected sex with a member of the opposite sex has been show to cause pregnancy in pre-menopausal women. This research has been peer reviewed ?

    But is that every encounter? No. In fact, only about 1 out of 104 encounters between heterosexual monogamous couples will result in pregnancy. Yet our species is spitting out babies like ice cubes in the dispenser. And I haven’t even provided the data on the number of pregnancies that don’t make it to full term!

    I happen to work for one of those “big evil pharma conglomerates” who make the vaccines for dogs. I’ll have to look and see if there is any data that correlates directly to acute IMHA within 3 days of receiving a vaccine(s)

    With respect, it doesn’t mean vaccines never cause IMHA, it just means that the direct correlations between vaccinations and IMHA are so low that the risk of not vaccinating outweighs the risk of vaccinating.

    Also, I must add, I agree with those findings. Even though I believe I experienced the small end of the percentile, and believe I lost an otherwise healthy and asymptomatic dog to IMHA days after receiving the 6 in 1 vaccine, I will still choose to vaccinate my dogs rather than not because the risks of declining outweigh the risks of vaccinating.

  11. skeptvet says:

    I’m sorry that happened to your pet! Of course, serious adverse reactions can happen, and it seems likely that rare cases of IMHA can be triggered by vaccines (though it has been very difficult to prove since it is so uncommon and since dogs are exposed to many potential triggers every day in the course of ordinary life). I don’t know about a “bad batch” since IMHA appears to be triggered by any antigen if the genetics and circumstances are aligned in just the wrong way, but there is a lot we still don’t understand about the disease. In any case, unnecessary vaccinations given due to rigid boarding policies rather than a considered evaluation of risks and benefits in consultation with your vet is certainly never appropriate.

  12. Math Guy says:

    2 out of 21 is actually 9.5%, not 30%. (Responding to The Other Science Guy’s second 9-4-17 post.)

    I’d say the basic mechanism of mammalian reproduction has been studied enough to qualify it as having been peer reviewed, and yet I still agree with your implication that, clearly, there is more work to be done by diligent researchers in the field.

  13. Jennifer says:

    There is little evidence because vets are not required to report adverse reactions. Even the AAHA website states this. https://www.aaha.org/guidelines/canine_vaccination_guidelines/vaccine_adverse_reactions.aspx

  14. skeptvet says:

    Perhaps, though as I said below

    1. We can’t assume more reactions are occurring than we know about any more than we can assume there are no unreported reactions. Guessing doesn’t make us any better informed or safer.
    2. If reactions are this mild and self-limiting, should they affect our vaccination practices? Does worrying about them, or even counting them if they actually occur, make us safer, or does it make us more afraid of vaccines, which can lead us to choosing vulnerability to serious disease over mild, self-limiting reactions to vaccines?

    Reporting without followup investigation has been shown to be a real problem since it creates the impression of risk even when most reported reactions turn out not to be related to vaccination. VAERS, for example, contains an enormous collection of anecdotes about adverse reactions. These are never investigated to identify any real connection to vaccination, regardless of what the people reporting them believe. And when controlled studies on vaccines are done, they show far fewer reactions, suggesting most reports don’t represent real adverse events. It does no good to collect anecdotes without properly vetting them because much of the time they don’t mean what people believe they mean, and the impression of risk they create is inaccurate.

  15. James says:

    Please help me. Out of sheer ignorance, stupidity, and frugality to save money, I took my dog, age 11, to Petco for 4 vaccinations for 7 different things all at once – rabies (was past due), DHPP, bordetella, and lepto. She was fine until 6 months later when she manifested a softball-sized tumor in her abdomen that was wrapped around the root of the mesentery and as such was deemed non-resectable. There were also multiple jejunal perforations and septic peritonitis. Please inform me what causal role an autoimmune reaction from these vaccines and adjuvants might have played in the development of this tumor. Also, the surgeon said the tumor showed what appeared to be collagenous fibers. What could this be? (mesenteric fibromatosis, sclerosing mesenteritis, fibrosarcoma, adenocarcinoma, extraskeletal osteosarcoma)?

  16. skeptvet says:

    I’m sorry that you went through this experience. Unfortunately, there isn’t any way I can determine the cause or type of your dog’s cancer or what role, if any, vaccines might have played in it. Sadly, older dogs often develop cancer. There is no evidence to suggest vaccines are a significant risk factor for this regardless of the timing, but no one has all the answers for these awful situations.

  17. Julie says:

    Hi there, as the owner of a now deceased puppy due to autoimmune disease, and having seen the system, I’m wondering if these diseases are being reported or studied at all. My dog got sick one week after his last round of puppy shots. He’d had a reaction to his first lot of shots and so the breeder requested I do a “killed parvo” shot at 12 weeks. I rang around 4 different local vets who either didn’t know what I was talking about, or said that the killed parvo didn’t work. The last vet I spoke to said he could do that shot but it would cost me $500 and convinced me all would be fine and just to go ahead with the normal schedule. He received anti-inflammatories and antihistamines with his 12 week shots. We just went ahead with the 16 week shots as normal. One week later he was at death’s door from meningitis and immune-mediated polyarthritis and he also had signs of immune-mediated thrombocytopenia. We kept him alive for a couple of months until we realised he would never be the same dog, and he was not happy or responding to the medication properly and had relapses often. All but one vet discounted my questioning of the vaccines as a cause. I asked the specialist if she’d report it anyway and her answer was, and I quote, “I don’t have to.” My thoughts are these.. these vets would have been more than happy to attribute the cause or trigger of these diseases to an infection or bacteria or parasite (all tests came back clear), but were not willing to say that injected disease components could also do the same thing. Also, aren’t vaccines designed to ‘trigger’ the immune system? His immune system was certainly triggered by something. Also, if no one is reporting these events, how do we know for certain? I suspect there are many, many people who would not consider vaccines to be the cause if it’s happening a week or more after the shots. I since heard a friend say their puppy dropped dead one week after his 12 week visit of unknown cause. No one questioned this. The vets I met all certainly would not have questioned if I hadn’t have. I have also been in contact with people who have received financial compensation to help pay for the vet bills due to autoimmune disease from the vaccine manufacturers. I’ve also read reports of adverse reactions stating that the autoimmune diseases my dog had were listed as “probable” or “possible” as the cause under certain vaccines. Heck, whilst doing research I came across a youtube video of a greyhound that entered rescue and then shortly after developed SLE/lupus. Of course, this dog would have entered rescue and had every medication and vaccination that was required. My point is, no one is asking the questions. No one is making the links. No one is reporting these events.

  18. skeptvet says:

    Unfortunately, the fact that you believe the vaccine is responsible for what happened to your pup doesn’t mean it is true. The problem is not that people haven’t studied the question, it is that studies haven’t turned out consistent with the idea that vaccines are a common cause of immune disease. When faced with a conflict between what seems like the case to us as individuals or what is consistent with the scientific evidence, most of the time it turns out we as individuals are mistaken not the evidence. This is understandably hard to accept, but it has proven true so many times, and much suffering has been eliminated by relying on science that we never succeeding in eliminating when we relied on anecdotes. I’m sorry for your loss, but I don’t believe it means what you think it means.

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