Does My Cat Really Need Another Vaccine? by Shawn Messionier, DVM

July 29, 2012

Dr. Shawn Messonier

When you get the annual reminder from your veterinarian this year telling you that it’s time for your cat’s booster vaccinations, ask yourself the following question: does my cat really need another set of vaccinations? While it’s important to have ongoing preventive health care for your cat, annual vaccinations may not necessarily be part of their preventive care. In this article I’ll share with you a more natural option to the standard recommendation of annual vaccines. 

The Pros and Cons of Vaccines

When used properly, vaccines can be life-saving for your cat. There are many infectious diseases that cats can contract that are not routinely seen thanks to vaccines. Feline panleukopenia virus infection, feline calici virus infection, and feline rhinotracheitis virus infection are not seen as commonly as they once were as most cats are vaccinated against these diseases.

Vaccines work to protect your cat against infectious diseases in one of two ways. First, vaccines can induce what is called humoral protection. Humoral protection occurs when white blood cells, B lymphocytes and plasma cells, produce antibodies when these white blood cells encounter the infectious particles contained in the vaccine. These antibodies circulate throughout your cat’s body, and will attack the infectious organism, preventing disease.

The second way in which vaccines induce immunity against infectious diseases is through cell-mediated protection. A different set of white blood cells, T lymphocytes, are activated by exposure to the infectious organisms contained in the vaccine. These T lymphocytes can directly attack infectious organisms and stimulate other cells to also kill the infectious organism, preventing disease. While this explanation of immunity is extremely simplified, it gives you an idea how vaccines work in keeping your pets safe from infectious diseases.

Vaccines can also work however, in an inappropriate or harmful fashion. With exposure to a vaccine, especially repeated and unnecessary exposure, the immune system may not work properly. The white blood cells which are activated by the infectious organisms in a vaccine might accidentally attack normal tissue in the pet’s body, causing what is called an autoimmune disease like lupus or pemphigus. No one knows exactly why this happens, but it is a very serious side effect that can occur when pets are given too many vaccines.

Acute vaccine reactions can also occur. While more common in puppies and in dogs, kidneys and cats can also develop an acute allergic response to any vaccine. These pets may develop itching, vomiting, diarrhea, difficulty breathing, hides, and even collapse in cardiovascular failure followed by death within minutes to hours following a vaccine.

Vaccines may also be linked to cancer in pets, through an abnormal reaction of the pet’s immune system. In cats especially, a certain kind of cancer called an injection site sarcoma can develop at the site of a vaccine. These sarcoma tumors are very aggressive and are reported to develop in 1 in 10,000 up to 1 in 1000 cats which receive frequent (annual) vaccines! This means that for every 1000-10,000 cats I vaccinate annually, I know I will directly cause the death of at least 1 cat! If this situation occurred in people, I’d have my license revoked and go to jail, yet this is considered acceptable in veterinary medicine.

Proper treatment involves surgical removal, radiation, chemotherapy, and various supplements to help slow down the growth of the cancer. It is not known exactly why some cats develop these tumors following vaccination. However, the pathology of the of the tumor suggests that some cats are genetically predisposed to developing chronic inflammation at the site of the vaccine. Since chronic inflammation can lead to cancer, it is thought that those cats genetically predisposed to this condition develop the tumor following excessive inflammation at the site of the vaccine. 

A New Approach to Vaccination

While vaccines can be an important part of preventive care for your cat, experts tell us annual vaccinations are not needed for most if any cats. We have wonderful vaccines available to us. All of them are capable of producing long-lasting immunity in your cat. This means that most cats will only require a few vaccines in their entire lifetimes. Since the maximum duration of immunity to any given vaccine in your cat is unknown, we can’t make a standard recommendation on how often your cat should be vaccinated. While many experts, including schools of veterinary medicine, recommend vaccinations every three years, we know that for many cats even this frequency of vaccination is excessive.

Fortunately, there is a simple and inexpensive way to determine your pet’s immunity. Determining your pet’s immunity to a given vaccine will allow your doctor to make a recommendation on how often your cat might require a vaccination. The test is called a blood antibody test, or more simply a titer test. The test measures one part of your pet’s immune system, the humoral immunity which measures antibodies. In our office, we measure a cat’s antibody or titer level against the following diseases: feline panleukopenia virus infection, feline calici virus infection, and feline rhinotracheitis virus infection. The test to measure the titers against these three diseases costs about $60. Results are received from the diagnostic laboratory within two to three weeks following the client’s office visit. Based upon the results of the test, it is been my experience that most cats only require vaccination a few times in their lives.

Unfortunately, the titer test is not a perfect test. It is however the only test which inexpensively allows us to look at an important part of your cat’s immune system. Without the information from this test, no veterinarian can accurately recommend a safe and effective vaccination interval.

While titer tests are used every day in doctors’ offices for diagnosing diseases, many conventional veterinarians still are opposed to using them in place of annual vaccination. The main complaint I hear from veterinarians is that they do not know how to interpret the results of a titer test. There is no agreed upon results for this test. In general, the presence of any titer indicates that your cat is capable of defending itself against infectious disease. Therefore, most veterinarians do not recommend vaccinating a cat which has any measurable titer. Other doctors like to see a titer of at least 1:4 or 1:20 or higher. If a titer of 1:4 or 1:20 or higher is not obtained, the veterinarian may vaccinate your cat.

While not perfect, using titer testing as a guide for vaccinating your cat is much better than vaccinating your cat every year, every three years, or based upon some other arbitrary recommendation.

Titer testing has proven itself in my practice and in the practices of many of my holistic colleagues around the world. Titer testing is inexpensive and is an easy way to take a look at an important part of your pet’s immune system. I recommend discussing this test with your veterinarian in an attempt to decrease the frequency of vaccinations in order to avoid unnecessary expense and minimize the chances of causing serious problems that can result from excessive vaccination.   

Posted with permission from Dr. Shawn Messonier, author of the award-winning The Natural Health Bible for Dogs & Cats and The Natural Vet’s Guide to Preventing and Treating Cancer in Dogs, among others. Dr. Shawn has  5 million satellite radio listeners on his award-winning show, Dr. Shawn-The Natural Vet, on Martha Stewart Radio Sirius/XM 110, Tuesday 7-8 PM CST.  

Related Articles:

Titer Testing: A Crash Course
Vaccines for Cats: We Need to Stop Overvaccinating by Lisa A. Pierson, DVM
Don’t Vaccinate Your Adult Cat for Distemper! by Jean Hofve, DVM


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2 Responses to Does My Cat Really Need Another Vaccine? by Shawn Messionier, DVM

  1. lloyd harrison on June 18, 2014 at 8:54 am

    my kitty is 14 years old and an indoor kitty but by law she must get the rabies vaccine still. 3years and 5 months ago she had the nobivac 3-year adjuvanted rabies vaccine and the year prior to that shot she had the purevac nonadjuvanted one. She had some reactions to each kind -and at that time I knew nothing about the difference in adjuvanted and non. Now that I know the problems with the adjuvanted,it seems best to choose the non-adjuvanted purevac for her now-but since it’s a one year vaccine only, she’d then be forced to get another each year-and as she ages, I’m thinking the re-vaccination each year wouldn’t be good for her either. therefore I’m in a quandary and need to soon proceed with one or the other. could you please – since I value your opinion greatly, give me your opinion? I’ve read your book and love it and its help -for people and pets–and all on your website too- but this exact answer I can’t seem to find in those writings. Thank you with all my heart! For your time in reading this when I know how busy you are and any advice you may have time to send me would be an answer to prayer!

    • adminjr on July 10, 2014 at 4:49 pm

      Lloyd, although this article was written by Dr. Messonier, what you have written won’t get to him. You might look at his contact into at Or you might search through the great articles at This is the site of a vet who loves, loves, loves cats, and she’s an expert on the subject.

      What I know is that adjuvants are especially dangerous for cats.

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