After years of research into the upsurge of vacccine-associated sarcomas (VAS) in cats, the American Association of Feline Practitioners created a set of vaccination guidelines designed to give cats the disease protection they need while minimizing the risk of cancer.
The guidelines, published in 2006, are used by almost all veterinarians. They specify which vaccinations to use, the frequency of vaccination, and the part of the cat’s body in which the vaccine should be given.
But now, a highly respected veterinarian is recommending another change: Stop giving adjuvanted vaccines to cats, immediately.
Dr. Alice Wolf, an internal medicine specialist and professor of small animal medicine at Texas A&M University, delivered that message to a packed room of veterinarians at the 83rd Western Veterinary Conference in Las Vegas.
Adjuvants are substances containing aluminum, which are added to vaccines in order to increase the body’s immune response. Ever since the AAFP concluded that adjuvants are strongly implicated in the development of VAS in cats, vaccines containing adjuvants have been listed in the “non-core” — to be given only to cats at high risk of the disease in question — section of their guidelines.
Vaccine-associated sarcomas were not seen before the mid- to late 1980s, when modified-live virus vaccines were removed from the market after cases of vaccine-induced rabies developed, said Wolfe. They were replaced by killed adjuvanted vaccines, including a new one for feline leukemia virus (FeLV).
The World Health Organization classifies veterinary vaccine adjuvants as a class 3 (out of 4 classes) carcinogen. Class 4 is the highest risk.
“If your doctor offered you a choice of two flu shots, one containing a class 3 carcinogen and one that didnt, which one would you choose?” Wolf asked the room. “Why would you make a different choice for your patients?”
The incidence of VAS is 1.3 in 1,000 to 1 in 10,000. What that means in real numbers is that up to 20,000 cats per year develop cancers as a result of vaccination.
Even one cat is too many if this is a problem we can avoid, Wolf said.
This creates a conundrum when it comes to rabies vaccinations. Is it better to give a nonadjuvanted recombinant vaccine each year, or to give a killed adjuvanted vaccine every three years?
In my humble opinion, it is better to give a much less reactive product more frequently than a much more reactive product less frequently, Wolf said.
Wolf cited a study by Dr. Julie Levy, the Maddies Professor of Shelter Medicine at the University of Florida, showing that modified-live vaccines were much more effective than killed vaccines, providing earlier onset of protection and protection of more animals. The recombinant vaccine for feline leukemia virus (FeLV) is as effective as the alternative.
In her talk, titled Feline Vaccination: Protocols, Products and Problems, Wolf also discussed whether cats need vaccines beyond the core rabies and FVRCP (feline viral rhinotracheitis, calicivirus, and panleukopenia). In most cases, the answer is no.
The vaccine for FeLV is universally recommended for kittens because they are most susceptible to the disease. Older cats, with fully developed immune systems, are much more resistant to FeLV. After kittenhood, vaccinate only if the cat is at high risk — that is, if and how often he goes outside, and if he’s exposed to other FeLV-positive cats in the household.
Which vaccines should cats not receive? Wolf listed those with little or no efficacy: giardia, feline infectious peritonitis, feline immunodeficiency virus, virulent calicivirus, and bordetella.
The bottom line: Ask your vet what he or she has read about the latest vaccine research. Veterinarians read professional journals and regularly take continuing education classes, so they are more likely to be up to date on their peers’ research than lay people. Ask what kind of vaccines your cat is getting — modified-live, recombinant, or adjuvanted killed virus. Then, work with your vet to develop a vaccination schedule tailored to your cat’s age, lifestyle and general health.
[Source: Pet Connection]
