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The Daily Vet by petMD

The Daily Vet is a blog featuring veterinarians from all walks of life. Every week they will tackle entertaining, interesting, and sometimes difficult topics in the world of animal medicine – all in the hopes that their unique insights and personal experiences will help you to understand your pets.

Vaccination Opt Out Letters

Recently it has become more common for owners to request that veterinarians write letters for various public health agencies or businesses stating their pets are too old, frail, or ill to receive vaccines. The reasons vary from a presumed fear that vaccines can cause problems or exacerbate existing problems to skepticism about disease risk to presumed parallels of reports of human side effects to vaccines.


The hope is that these letters will prevent exclusion from services such as air travel, boarding and day care, grooming, and most importantly, licensing, despite the lack of vaccinations. What is interesting about this phenomenon is that it is increasing despite the fact that vaccination protocols in pets are commonly every three years instead of the old yearly protocols.


The Legal Right to Opt Out of Vaccinations


There is no legal requirement for pets to be vaccinated for diseases that protect their health. Vaccines that help prevent the common well known infectious diseases of cats and dogs were all developed to improve the health of pets and reduce the contagion of these major diseases.


Because pets are considered property, it is the owners’ right to determine the level of health protection they wish for their pets, and they are free to choose which vaccines they want or whether to vaccinate at all. It is also the right of any business, even veterinary hospitals, to deny services to unvaccinated animals in order to protect the health of other pets and patients. More and more pediatricians are denying service to parents that have opted out of vaccines for their children. These doctors fear potential waiting-room contagion in other yet-to-be vaccinated children or those that may have yet to develop full immunity.


Immunity is not necessarily established after one or two sets of vaccines (also a subject for a future blog) in humans or pets. Also, many diseases in humans and pets are on the rise again due to parents and pet owners opting out of vaccinations against these diseases.


All veterinarians agree that there are occasions when vaccines can be delayed until a pet’s condition is resolved or improved. But absolving an animal from all future vaccinations simply because it is has a chronic condition or is old is questionable. There is no hard, universal evidence that vaccinations are detrimental to these animals or that they will cause disease or cancer. In fact, unvaccinated infirm or geriatric animals may be at higher risk if exposed to contagious diseases.


Vaccine reactions most commonly occur in younger pets, not in older, ill pets. Animals that have had previous allergic episodes can generally be pretreated with medication to prevent or minimize vaccine reactions. With the exception of previous, vaccine-specific anaphylactic reactions (life-threating systemic failure), opt out letters are not appropriate for animals with a history of allergic vaccine reactions.


Rabies and Pet Licensing


Rabies vaccines are not given to pets to protect the animal, they are given to protect humans. Public health departments, the agencies that determine rabies vaccine protocols, are only concerned about the welfare of humans, hence all of the regulations regarding rabies vaccines, especially in dogs. These regulations are not without reason. With the exception of three children in recent years, rabies is always fatal once a human begins to display symptoms. The American Veterinary Medical Association reports 55,000 annual deaths worldwide due to rabies and 1-2 deaths annually in the U.S. Skunks and bats are the leading vectors of rabies in the U.S. In some areas fox and coyotes are also a threat. Because many states classify cats as wanderers they are not subject to public health laws related to rabies except in individual jurisdictions. This short story will demonstrate why this is a problem.


I have always required that my patients have a current rabies vaccine in order to protect my staff, in case they are bitten by an uncooperative pet. I had a client who insisted that she would not comply and I politely refused her further veterinary services. Two years later she came back to the practice somewhat apologetic. It happened that a bat flew into her apartment and bit her two unvaccinated cats. The bat was found to be rabid. The cats were immediately vaccinated and all turned out well. What might have happened if the bat had escaped without her knowing that it bit the cats?


There is no evidence that a rabies vaccine every three years will harm older or chronically ill pets. Research indicating the association of vaccines, particularly rabies vaccines, and fibrosarcoma in cats has yet to prove a cause and effect.


With rare exceptions, opt out letters are not appropriate for rabies vaccines.



Dr. Ken Tudor



Image: Byelikova Oksana / via Shutterstock


Comments  17

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  • There is too evidence!
    05/30/2013 12:16pm

    Dr. Tudor writes: "There is no evidence that a rabies vaccine every three years will harm older or chronically ill pets." --- Yes, there is. Why must you write in such absolute terms when you have not done the necessary research?

  • 05/30/2013 03:30pm


    Thanks for your comment. It is so right.

    I lost a cat to Vaccine Associated Sarcoma two years ago due to a rabies vaccine. There is belief that littermates may have a genetic link to this disese, and I will not vaccinate my surviving littermate again due to this health concern.

  • 05/30/2013 10:43pm

    PLEASE address the fact that my Chihuahua (on heart meds and high blood pressure meds) (age 11) should take the rabies vaccination when he had a severe allergic reaction the last time he was given it!?

  • reactions & fibrosarcomas
    05/30/2013 03:59pm

    I was just listening to a podcast yesterday from Dr Ron Schultz, the pre-eminent vaccine scientist and researcher in the US. There is plenty of evidence that vaccines confer risks for adverse reactions, particularly among immunocomprominsed animals, and there is a DIRECT link between rabies vaccine and fibrosarcoma in cats. The risk of an adverse reaction must be weighed against the benefit of disease resistance that vaccines provide.

  • What about titers?
    05/30/2013 04:53pm

    You forgot two VERY important things:

    1. Titers (blood tests) can be done to prove a dog still has immunity from prior vaccines that have been given, such as rabies and distemper. Titer results are becoming widely accepted in lieu of proof of vaccination. This is a great solution for the pet owner who is concerned about giving vaccines to sick or older pets who have received vaccinations in the past. Some titer results are showing that certain dogs retain immunity through adulthood after getting their 1 yr boosters. Each dog is different so you can't assume, you have to titer.

    2. Not a whole lot is known about the longevity of specific vaccines and it's quite possible that older pets who have received regular vaccines as puppies and young adults can retain that immunity through their senior years without having to be re-vaccinated (again, titers come in handy). The vaccine protocols started out as a best guess and over time, the recommendations have changed as more research has proved the longevity of some vaccines. Dr. Jean Dodds is just one person who's leading a study into the longevity of the rabies vaccine in hopes of improving vaccine protocols.

  • Vaccines are dangerous!
    05/30/2013 05:38pm

    Why is there no mention of the biggest baddest white elephant in the room when one talks about vaccines - VAS!

    Less risk as they get older my foot. Allergies and reactions can happen at any stage in one's life.. feline / canine or human!!

    Giving the rabies vaccine every three years for a cat is much more dangerous. the three year vaccine has been shown to have higher incidents of VAS then the 'Safer' one year vaccine (which also has some incidents of vas)

    why is it we give 1cc of vaccine to a 1 lb pet and 150 lb pet? doesn't that seem a little extreme and dangerous? Incidents of VAS are much higher the smaller the animal.

    Lastly, you also do not discuss how long the vaccines are safe for. The current protocol is no more often then every three years, implying that the vaccine is actually effective much longer then three. I recently read that it has been shown to be effective up to seven years..

    if vets are so darn worried about their staff (and I'm not saying they shouldn't be) then they should be worried even when a pet is vaccinated. No vaccine is 100% protection. The staff can also be vaccinated for rabies which would also help in reducing the risk. and if you were to be aware of the human rabies vaccine, you would know that it isn't given every year.. or every three years..

  • Rabies Vaccine
    05/30/2013 07:38pm

    Your anecdote covers a situation very close to what happened in our home a couple of summers ago. I was greatly relieved to only have to worry about myself when our FIV+ cat decided to encourage a bat to come in through a door accessing our deck, that was open for his exercise time late in the evening. We had just taken this cat in for his booster vaccine after thinking it over carefully because of his FIV status, and advancing age. As the bat was able to fly back and forth through the ceiling fan blades while the fan was on, it was very difficult to escort it back outside, especially as I already had to worry about my own protection. Cats can sense our emotions and it was good that our FIV boy wasn't sensing that I was afraid for him. It kept him more calm, and gave me the opportunity to think clearly and 'escort' the threat out of the house with the use of a screen from one of the windows.

    As our cat was already immune compromised with his FIV status showing worse each year in lab reports, you would expect that he, if any cat, would have a reaction to vaccines, but he didn't.

    And, as you stated, there is no credible scientific data showing a connection between sarcomas and vaccinations, or surely the detractors of your post would have been smart enough to include them in their attacks.

    However, I do think that as titer testing shows cats to still carry plenty of immunity after three years, I personally thing that a bit more flexibility should be available to owners who need it, AS LONG AS THERE IS A PAPER TRAIL, showing regular previous vaccinations. And of course, again, I am suggesting vaccinations other than the rabies vaccine as it is a threat for humans.

  • 05/30/2013 08:19pm

    Westcoastsyrinx writes: "And, as you stated, there is no credible scientific data showing a connection between sarcomas and vaccinations, or surely the detractors of your post would have been smart enough to include them in their attacks." --- Fibrosarcomas aside, the journals are replete with evidence that repetitions of rabies vaccinations have caused severe damage to older or chronically ill pets. I'm not going to do Dr. Tudor's homework just because he refuses to and yet insists upon making such absolute conclusory statements.

  • 04/13/2016 12:19am

    Wrong - it IS recognized and is called vaccine-associated sarcoma. It's killed both cats and dogs. I know of several. One was my sister-in-law's cat. She educated herself and has never again vaccinated any of their animals. They've been much healthier and lived longer, too. Vaccines are insanity and it's being recognized my greater numbers worldwide. Injecting disease, toxins, chemicals and blood/cells of other species can never bring health. Natural immunity will protect against viral diseases; that comes by exposure through the nose or mouth. Injection is unnatural and all vaccines cause harm, brain inflammation, and immune system suppression/confusion. Vaccines do not immunize; they sensitize - big difference.

    Juliette de Bairacli Levy prevented and cured distemper, parvovirus, rabies and more using only natural means of herbs, fasting, etc. but was unable to save those who were vaccinated and ate an unnatural diet (pet foods, kibble and other such poor nutrient foods).

    Google Edward Jenner's son to learn that he died at age 21 years after suffering poor health for many years. The result of being his father's vaccine guinea pig. You can also find stats on how much healthier unvaxed people are vs. vaxed. The same is true for animals. There is NO study - not even one - proving vaccination is safe. It makes big money for pharma and those who vaccinate. This is why it continues despite the billions of vaccine damaged lives.

  • Timing
    05/30/2013 09:31pm

    "a bat flew into her apartment and bit her two unvaccinated cats. The bat was found to be rabid. The cats were immediately vaccinated and all turned out well."

    I wasn't aware that a rabies vax could be given AFTER the animal has been bitten by a rabid critter. Is it a timing thing? If so, how quickly should a vaccination be given after an animal has been bitten by a critter known to carry rabies?

    I was also under the impression that the is a time frame necessary - maybe two or three weeks - before a rabies vaccination takes "full effect". Is that not true?

  • 05/30/2013 10:03pm

    It would be true if there had been no previous vaccinations. My understanding was that the person just chose to stop providing boosters, but that the cats may have had residual immunity from previous shots. I would presume one would need proof of previous vaccinations and when they were performed in order to prevent the cats from being euthanized.

    I know that we went to the trouble of having titers done on cats and ended up not doing boosters for the FIV+ boy for about seven or eight years, but had moved to a new area with a veterinarian who wanted the reassurance that our cats were covered to protect all animals coming to her clinic, which was an understandable precaution. As we had moved to a place where we could build a fence around a deck for our cats, they had more exposure than previously, so updating seemed the logical option at that point. As we had the encounter with a bat, I was extremely relieved and we do always stay currant with the rabies shots, in spite of thinking that possibly our cats could go longer between boosters.

  • 05/31/2013 01:36am

    I had the same exact same questions! This is a very interesting post as I've heard the same about the use of Titers to determine if vaccinations were necessary. I smell another blog post about Titers coming up.


  • vets should offer titer
    05/31/2013 02:53am

    As I have already told my stories before I wont tell you again,but my vets hate my internet research.But there are too many real life stories to ignore.I would like more articles about lyme vaccines.I only know that people( who can talk,)complained of severe side effects when it first was introduced for humans,forced it off the market.So why is it O.K. for our pets every year?Why is it people who love their pets(that I know personaly in my area)who can't afford these vaccines have healthier pets than me?I who love my pet so much I take him for everything that the vet says he needs all the time.Oviously its not the money,although I'm not rich,I'll put off my dentist for his scheduled vaccinations.When I mentioned titer instead to all the vets in my area,they say they don't offer that and its very expensive.I took 6 months off of vets visits and my baby is much healthier.I say vets have to research as much as we do,offer titers,and also prescriptions we can fill at our pharmacist for cheaper instead of buying them over their counter without even telling us of the option.I've been sacrificing too much only to love my baby" to death"

  • 06/03/2013 02:02pm

    Dr. Ronald Schultz, who is the top researcher in companion animal vaccines, only gives his pets the kitten/puppy round of vaccines and one follow-up booster. He titers them to make sure they have immunity and then doesn't do any more boosters for the rest of their lives. He gives the rabies boosters according to legal requirements "not because they immunologically necessary".

    Here's a good interview with Dr. Schultz: http://www.youtube.com/watch?v=L1Xd5ghnlJ4

    That doesn't mean everyone should do the same thing as Dr. Schultz does with his dogs and cats, but it says something. And like he says "there's probably no one who knows more about vaccines than me."

    Hopefully with the research from the Rabies Challenge (Fund), the legal requirement for rabies boosters will be extended. Dr. Schultz is involved in this important research. http://www.rabieschallengefund.org/education

    The issue about requiring vaccines for pets to be able to receive vet care is understandable, but that's where titers need to be more accepted and used, and there should be more guidelines for older or sick animals (those that have had vaccinations and boosters in the past). I've not had titers done yet, but was given a price from a holistic vet and it was only $100 for a rabies titer. I've often heard they are so expensive, but are they really? Also, how many older cats who have been vaccinated at some point actually get panleukopenia (the main disease cats are vaccinated for, other than rabies)?

    This is not a simple topic, and yes, certainly cats and dogs need to be immunized (different from being vaccinated, as Dr. Schultz says), but there will be more and more clients concerned about the issues of over-vaccination and we more info and better guidelines around the whole topic.

    Here's some more good information from Dr. Lisa Pierson about feline vaccines: http://www.catinfo.org/?link=vaccines

  • NOT
    09/11/2014 05:36am

    A link from your own web site.. You are killing dogs with your ignorance.
    Objective—To determine incidence rates and potential risk factors for vaccine-associated adverse events (VAAEs) diagnosed within 3 days of administration in dogs.
    Conclusions and Clinical Relevance—Young adult small-breed neutered dogs that received multiple vaccines per office visit were at greatest risk of a VAAE within 72 hours after vaccination. These factors should be considered in risk assessment and risk communication with clients regarding vaccination. (J Am Vet Med Assoc 2005;227:1102–1108)

  • 09/11/2014 03:42pm

    @Fishstick, I notice you didn't care to impart the full set of information from that sight.

    First, it was an "adverse event" which does not necessarily fall under the category of "killing" as you put it.

    Second, this is about the NUMBER of vaccines given per office visit, and as the number increases so does the risk, (well duh!).

    Third, it doesn't clarify whether the dogs "under" 10 pounds were given a full dog dose of these vaccines that I can see, and seeing as a 10 pound dog is smaller than a cat, I would personally want to discuss this with my veterinarian.

    I am not advocating the giving of more than just a rabies vaccine to miniature dogs that have no contact with the outside world, ergo no risk, but it is also clear you are an "anti-vaxer" activist as you don't mind distorting factual information on this topic AND you are only seeing the abstract of the study on the reference you have given. I would suggest that if a dog owner is concerned they should discuss with their veterinarian about the range of "adverse effects reported" in this paper, but there may be situations where a dog owner needs the vaccinations done, and perhaps looking further into the results of this paper for severity of "adverse reactions" might be an idea.

    One must presume you went searching on the net after watching NOVA yesterday and are not happy with the message given around vaccinations, in spite of the factual information given in the program.

  • 09/11/2014 03:58pm

    After reading the full paper I notice that the statistics for rabies alone, which is very important for our pets, is dropped by half over the statistics for multiple vaccines. and the larger the dog, the lower the "incidents of adverse events" which includes what veterinarians would consider an allergic reaction. It might be an itch for all you know.

    I wasn't impressed with this paper in that there was too much discretion on the part of the veterinarians, and 3 days is not enough time for a full picture of possible "adverse" reactions, as well as the fact that this paper doesn't point out that CORRELATION DOES NOT EQUAL CAUSATION. We don't know if the dog's food became an issue after vaccination or what other problems might have occured. Poor quality study.

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