Vaccination Policy
Are We "Overvaccinating" Cats?
Lately some cat owners and some researchers have wondered whether we may not be "overvaccinating" cats. Do they need to be vaccinated yearly; does the immunity last only one year? Are there any currently recognized problems associated with vaccination? Are there likely to be unrecognized problems?
IMMUNITY - In August 1997 a controversial article published in the veterinary journal Feline Practice by researchers at the Cornell Feline Health Center suggested that immunity produced by the Feline distemper, Calici, Herpesvirus (3 in 1) vaccine may last several years. This could be true as well for the Feline Leukemia Virus vaccine and has long been known to be true for some Rabies vaccines. Why then have we been vaccinating cats yearly? The academic answer would be because it has not been practical to check the level of immunity of each cat for each vaccine, or because it would be too expensive to do so, and so the safest course of action would be to just vaccinate yearly. If the aforementioned study is valid then things may be changing; it may be reasonable to vaccinate at less frequent intervals.
PROBLEMS
The highest profile problem discussed lately in relation to feline vaccination has been vaccine induced cancer. These tumors are generally sarcomas, occur at the site of Rabies and/or Feline Leukemia Virus vaccinations and can be malignant and aggressive. They occur in approximately 1 in 10,000 vaccinated cats. Why this has only been noticed recently, and why they are associated with these two vaccines is not definitively known. Conceivably they have been around for a while and their relationship to vaccination sites not recognized. Some researchers believe that an adjuvant added to the vaccine to increase its effectiveness may have something to do with these tumors. This problem has been one of the spurs to the vaccination-frequency controversy.
The simple reaction to the above is to not vaccinate. As someone smarter than me said, "Any philosophy which will fit in a nutshell belongs there." The diseases for which we vaccinate still kill far, far more cats than the tumors so this solution is not entirely rational.
UNRECOGNIZED PROBLEMS
When any regimen of medication, natural or synthesized, vitamins, food, or exercise is contemplated an overwhelmingly important question is what are the risks? Many times these risks are known, printed on the package, contained in the product insert but many times not. The risks of allergic reactions, local tissue reactions and now tumors are recognized but what about the unknown? The whole thrust of vaccination/immunization is to modulate the immune system, to manipulate it, change it in order to protect the animal. Perhaps then, in this process, unintended changes are made to the immune system. Immune diseases like lupus, hemolytic anemias, allergies, rheumatoid arthritis result from dysregulation of the immune system. Are some of them caused by or exacerbated by vaccines? Possibly. More than that is hard to say at the moment. But even if this is not known that does not mean that we cannot take some action.
APPROPRIATE ACTION
It seems as though a small number of tumors may be associated with Rabies or Feline Leukemia vaccines. It is also true that many more cats suffer from the diseases prevented by vaccines. It is a cause of concern to some researchers that constant stimulation and manipulation of the immune system may have unintended effects. It also seems that the vaccines we have been using may be more effective in most cats than previously known.
So what is the appropriate action? Perhaps appropriate response is to tailor the vaccination regimen to the individual cat. I think that all cats should be vaccinated as kittens. Cats with very little exposure probably need infrequent vaccination. Cats with significant exposure, outdoor cats, cats that escape from the house every week or so, cats who travel may need vaccination but less frequently than previously thought, perhaps every two or three years. Bottom line? Vaccinate only as much as necessary to protect the cat in question.
©2008, Matthew J. Ehrenberg
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Lately some cat owners and some researchers have wondered whether we may not be "overvaccinating" cats. Do they need to be vaccinated yearly; does the immunity last only one year? Are there any currently recognized problems associated with vaccination? Are there likely to be unrecognized problems?
IMMUNITY - In August 1997 a controversial article published in the veterinary journal Feline Practice by researchers at the Cornell Feline Health Center suggested that immunity produced by the Feline distemper, Calici, Herpesvirus (3 in 1) vaccine may last several years. This could be true as well for the Feline Leukemia Virus vaccine and has long been known to be true for some Rabies vaccines. Why then have we been vaccinating cats yearly? The academic answer would be because it has not been practical to check the level of immunity of each cat for each vaccine, or because it would be too expensive to do so, and so the safest course of action would be to just vaccinate yearly. If the aforementioned study is valid then things may be changing; it may be reasonable to vaccinate at less frequent intervals.
PROBLEMS
The highest profile problem discussed lately in relation to feline vaccination has been vaccine induced cancer. These tumors are generally sarcomas, occur at the site of Rabies and/or Feline Leukemia Virus vaccinations and can be malignant and aggressive. They occur in approximately 1 in 10,000 vaccinated cats. Why this has only been noticed recently, and why they are associated with these two vaccines is not definitively known. Conceivably they have been around for a while and their relationship to vaccination sites not recognized. Some researchers believe that an adjuvant added to the vaccine to increase its effectiveness may have something to do with these tumors. This problem has been one of the spurs to the vaccination-frequency controversy.
The simple reaction to the above is to not vaccinate. As someone smarter than me said, "Any philosophy which will fit in a nutshell belongs there." The diseases for which we vaccinate still kill far, far more cats than the tumors so this solution is not entirely rational.
UNRECOGNIZED PROBLEMS
When any regimen of medication, natural or synthesized, vitamins, food, or exercise is contemplated an overwhelmingly important question is what are the risks? Many times these risks are known, printed on the package, contained in the product insert but many times not. The risks of allergic reactions, local tissue reactions and now tumors are recognized but what about the unknown? The whole thrust of vaccination/immunization is to modulate the immune system, to manipulate it, change it in order to protect the animal. Perhaps then, in this process, unintended changes are made to the immune system. Immune diseases like lupus, hemolytic anemias, allergies, rheumatoid arthritis result from dysregulation of the immune system. Are some of them caused by or exacerbated by vaccines? Possibly. More than that is hard to say at the moment. But even if this is not known that does not mean that we cannot take some action.
APPROPRIATE ACTION
It seems as though a small number of tumors may be associated with Rabies or Feline Leukemia vaccines. It is also true that many more cats suffer from the diseases prevented by vaccines. It is a cause of concern to some researchers that constant stimulation and manipulation of the immune system may have unintended effects. It also seems that the vaccines we have been using may be more effective in most cats than previously known.
So what is the appropriate action? Perhaps appropriate response is to tailor the vaccination regimen to the individual cat. I think that all cats should be vaccinated as kittens. Cats with very little exposure probably need infrequent vaccination. Cats with significant exposure, outdoor cats, cats that escape from the house every week or so, cats who travel may need vaccination but less frequently than previously thought, perhaps every two or three years. Bottom line? Vaccinate only as much as necessary to protect the cat in question.
©2008, Matthew J. Ehrenberg