Monday Medical: Tail vaccine followup

Back in November we shared with you a breaking news story about a potential new vaccine protocol for cats.

This study examined the pros and cons of a vaccine administered toward the end of a cat's tail.

It was a novel approach and I really liked the general concept, since as many as 1 in 1,000 cats vaccinated will develop a cancerous tumor known as a fibrosarcoma.

(You can read more about fibrosarcomas and the tail vaccine study here.)

Should a vaccine-associated sarcoma (VAS) develop, a tail amputation might give a cat a much greater chance of survival than if it were delivered behind the shoulder blades or in a lower limb.

Dr. Sara Huber with one
of her 4-legged patients

But I wanted to know what animal practitioners thought of this idea. So I asked Dr. Sara Huber, one of the veterinarians at Leawood Plaza Animal Hospital, what her opinion was of the study's results.

Dr. Huber: "I think that the research is definitely promising. However, one study does not a protocol make.

"I base my vaccination protocols on the recommendations put in place by the AAFP. They base their recommendations on a large body of research and come to a consensus based on this research and what is best for the welfare of the pet.

"In theory, vaccination at the caudal third of the tail makes perfect sense. If a tumor were to develop, a tail amputation can be done quickly, easily, and with relatively little pain to the pet."

It does sound promising. But is it too soon to jump on the bandwagon? Knowledgeable friends and bloggers have expressed concern that misdelivered vaccine injections might end up in the nerve branch of the tail's spine.

I would imagine that would be painful for your pet. Plus, what kind of danger might that pose to a cat? 

We love the elegant curve of Maxwell's tail.
Still, we'd amputate in a heartbeat if it meant we could keep him alive.

As of now, these questions - as well as long term side effects of tail vaccines - have yet to be addressed.

Sara does find it promising that they seemed to get less of a reaction to vaccination in the tail than the distal hind limb. But she also finds it somewhat hard to believe.

Faraday agrees: vets are
SCARY. (But Dr. H is NICE)

"The study included 'only cats that were tame'," she told me, "which truthfully is not really representative of the average cat at the vet. They are frightened and stressed out and many of them do not just agree to sit quietly and accept a physical and vaccines.

"And I can't say I blame them! Its scary being put in a box and thrown in a vehicle and poked and prodded!

"I imagine that there will be a lot of vaccines going through the skin and ending up on the table. I personally would like to see more evidence based research on this topic prior to completely changing my protocol."


Sara also reminded me that "a discussion on sarcomas has to involve adjuvanted vs. non-adjuvanted vaccine." An adjuvant is a chemical added to a vaccine, oftentimes in an attempt to either stabilize the vaccine, increase its shelf-life, or increase the immune response in the one being vaccinated. Adjuvants have been identified as cancer-causing in cats. And they're not limited to vaccine injections, either. Some recently developed injectible flea repellents with adjuvants have been associated with cancer as well.

Sara argues that "with the greater options of non-adjuvanted vaccines available to us, we are able to reduce the risk of a chronic inflammatory reaction from the adjuvant and hopefully lower the chance of developing an injection site sarcoma while still adequately protecting our patients from disease."

Still, she concluded, "vaccine associated sarcomas are horrible. It is a topic that I think is very important to discuss with clients when designing a vaccine protocol for their specific pet."

We agree - and pray that research will continue until VAS becomes a topic found only in veterinary history books.

Monday Medical Disclaimer: 
I am not a veterinarian, and the information provided here is not intended in any way as a substitute for professional veterinary care. Nor should it be used to self-diagnose for your pet. This information is for educational purposes and to provide you with reputable documentation you can use to pose informed questions of your own to the veterinarian of your choice.

BREAKING: Tail vaccine for cats may save lives

We have long known that vaccines can cause cancer in cats at the injection site. And when it occurs, fibrosarcomas caused by vaccine have been found to be more virulent and aggressive than ones that naturally occur.

This has been established as a known factor, specifically for rabies and feline leukemia vaccines, says the University of Florida's Small Animal Hospital.

Dr. Julie Levy of the University's College of Veterinary Medicine commented that “one to ten cats out of every 10,000 vaccinated against infectious diseases develop cancer at the vaccine injection site.”

Historically, the injection site was located between the shoulder blades, which made treatment - excision of the tumor with clean margins - virtually impossible.

So in 2006, the Winn Feline Foundation recommended that the injection site be moved to a location where a tumor might more easily be removed.

The location recommended was either a front or back leg. The AAFP (American Association of Feline Practitioners) went even farther, suggesting the injections be made below the elbow or knee joint.

Studies of cats whose injection sites had moved to an intramuscular location such as the leg then began to show an increase in fibrosarcomas at that location. This uptick put to rest any doubts that vaccines (and possibly the adjuvants added to the vaccine to increase its effectiveness) were indeed to blame.

So it's fairly well accepted that in a small percentage of cats, this cancer will occur. And, Dr. Levy points out, even though this is a small percentage statistically, that's still thousands of cats each year who will be diagnosed with it.

Which is why a news release from the University of Florida veterinary college published October 31 brought some very welcome news:  

Julie Levy, D.V.M., Ph.D., and Maddie’s Professor of Shelter Medicine, unveiled the results of a study just completed where they looked at the impact of moving feline vaccine injection sites to the tip of the tail.

Their findings indicated that administering vaccinations in the tip of the cat’s tail was just as effective as vaccines given in traditional locations.

Tail vaccination allows for a far more effective surgical treatment of any cancer that will occur near the site, Levy says.

And because such treatment is less invasive (thus less expensive), she hopes that it will be something more pet owners would be willing to treat.

Treatment to the tail would also be less disfiguring for the animal - another plus. 


One major concern of those participating in the study was how well the injections would be received by the patient!  U of F veterinary student Cleon Hendricks, one of the participants in the research study, admitted to some apprehension. He was pleasantly surprised to find that the cats accepted vaccination in the tail just as well as they did in the leg!

UPDATE: We were unaware that a drug had been developed to deliver a six-month systemic flea prevention through injection, but discovered it in the course of researching this article. Please do not accept this for your pet if offered. The drug, called Program, has also been found to cause cancer in cats. Besides, you need to protect your cat for heartworm anyway, and monthly topical treatments that provide that protection will also handle fleas and ticks. 'Nuff said.

__________
Sources:

National Institutes for Health Article archive

VetMed's Shelter Medicine site library
University of Florida's College of Veterinary Medicine New Release
AVMA on the web
U of Fla Small Animal Hospital, on vaccination and sarcomas
Current studies on tail vaccination in cats
Vaccines - do our cats really need them?
Eigner, Diane R. "Feline Vaccine Guidelines". The Winn Feline Foundation. Retrieved 2006-08-27.
Cleon Hendrick's article on his experience participating in the study
Centers for Disease Control: About Adjuvants
Information on Vaccine-Associated Sarcomas