>From 2005: http://www.avma.org/journals/javma/articles_public/vafstf_050601.asp
"DR. JANE BRUNT: I've seen vaccine-associated sarcomas, as have my colleagues. It seems clear to me and my colleagues in AAFP that results of additional studies are not needed to prove that there is an association between vaccine administration and sarcoma formation in cats. On the other hand, there are a number of others who have not seen a vaccine-associated sarcoma, and they are more inclined to continue to vaccinate as they always have. Veterinarians' belief in the association between vaccine administration and sarcoma formation depends on what their experience has been." "DR. HENDRICK: My opinion, on the basis of what I know about basic pathology and what I have observed, is that cats have a predisposition to develop sarcomas in response to inflammation, but something changed in 1989. Suddenly, we started seeing more sarcomas than the sporadic ones that we would have seen after administration of various injectables. In my opinion, what changed was new formulations for vaccines. In some way, they promoted a more robust, unusual, or exuberant inflammatory response and that led to an increase in the development of sarcomas. Something happened and not just because of the higher frequency of vaccine administration, compared with other injectables. Cats have been receiving vaccines more often than lufenuron, fluids, or methylprednisolone acetate sterile aqueous suspension." "DR. THOMAS ELSTON: Regarding the AAFP/AFM's recommendations on the use of FeLV vaccines, there is at least potential for a change in the occurrence of fibrosarcomas. The AAFP/AFM guidelines28 recommend that FeLV vaccines be used only in those cats at risk of direct exposure to FeLV-infected cats. With lifestyle changes in this country, we are seeing more and more cats being housed totally indoors, as much as half of the cat population. With this much of the cat population at low to no risk, the use of FeLV vaccine should, at least in theory, have decreased significantly. The effect of that should be a reduction in FeLV vaccine site fibrosarcomas. An example of that effect in an admittedly small sample size is that in my practice, where 90% of my patients no longer receive FeLV vaccines, during the last five years, I have not seen any fibrosarcomas associated with FeLV vaccines but continue to see as many fibrosarcomas associated with administration of rabies virus vaccines." (note that this translates into the fact that BEFORE, when he gave the FELV vaccine routinely, he WAS seeing FELV vaccine induced sarcomas) "DR. GLICKMAN: Monitoring the ratio of vaccination site to nonvaccination site sarcomas is a good indicator of change, even if numbers of submissions of masses to laboratories vary. Results of one study clearly indicate that the ratio of vaccination site sarcomas to nonvaccination site sarcomas seen in a typical diagnostic laboratory has increased dramatically. In 1989, the ratio was 0.54, meaning there were half as many vaccination site sarcomas as there were nonvaccination site sarcomas. A year later, the ratio was 1.0; it more than doubled. In 1991, the ratio was 1.47; in 1992, it was 1.86; in 1993, it was 2.6; and in 1994, it was 4.3.27 We haven't followed it beyond that. This type of data can be collected from various laboratories to see if there is concordance and to get an idea of whether the problem is getting worse or getting better." and this, from lower on the same page, not directly related to the question of if there is newer evidence, but yet this is a respected veterinary professional's opinion on the need for the FELV vaccine, and thus I feel it deserves to be read by anyone considering using this vaccine (especially since I was just pointing this out in my last reply, without the source to quote from): What guidance can we provide to veterinary practitioners? DR. SCHULTZ: Because adjuvanted FeLV vaccines have been implicated in vaccine-associated sarcoma development, I suggest limiting FeLV vaccination even beyond the current AAFP/AFM recommendations. There is a strict age-related susceptibility to FeLV. Approximately 90% of kittens younger than three weeks old will become persistently infected when sufficiently challenged. Between three weeks and three months of age, approximately 50% will become infected when similarly challenged. Between three months and approximately nine months of age, the number decreases to approximately 30%, and over a year of age, the number is < 15%. Results of an independent study 66 indicates this, as do results of every manufacturer of an FeLV vaccine. For FeLV, my current recommendation is to vaccinate the kitten that is at risk, and virtually all kittens are at risk. You can rarely determine what a kitten's lifestyle is going to be, and kittens are at the greatest risk of infection because of the age-related resistance to FeLV infection that develops in cats as they mature. If the cat is still at risk of exposure at a year of age, then revaccinate at that time. Thereafter, I recommend never revaccinating the cat. I don't know the incidence of vaccine-associated sarcomas associated with FeLV vaccines, nor do I know the risk of a nonvaccinated cat developing FeLV-associated disease, but I would suggest that the risks are probably about the same. In fact, it's possible that the risk of developing a vaccine-associated sarcoma may even be greater than the risk of developing FeLV-associated disease. With the prevalence of FeLV viremia between 1% to 3% nationwide, the fact that FeLV is not highly contagious, and the fact that adult cats have extraordinary innate resistance to persistent infection, the risk of FeLV infection in cats vaccinated according to this recommendation is probably 0.001% to 0.0001%. Ironically, I believe that cats at greatest risk of developing persistent infection (ie, cats younger than four months old) actually receive little or no benefit from the vaccine. Effective immunity requires two or more weeks to develop after administration of the second dose of vaccine, by which time those cats are at least 12 weeks of age and are developing innate resistance. Phaewryn http://ucat.us/domesticcatlinks.html Special Needs Cat Resources
