Vaccination site tumors...vaccinations save the lives of countless cats each year. But while vaccinations will continue to be life savers, owners need to keep in mind that vaccines are not a panacea. And, as with human vaccines, feline vaccines carry some small degree of risk.
Be selective choosing the cat vaccines that are really necessary, research the effectiveness prior to a feline vaccine. The rabies and FeLV (feline leukemia virus) killed vaccines have been investigated.
Back in 1991, two veterinary pathologists...Drs Mattie Hendrick and Michael Goldschmidt...at the School of Veterinary Medicine at the University of Pennsylvania reported on an increase in certain soft-tissue tumors (fibrosarcomas) at the most common injection sites for feline vaccines.
The increase followed on the heels of a mandatory rabies vaccination program in Pennsylvania. Later investigations studied cats diagnosed with fibrosarcomas. The results of the studies confirmed that there is, indeed, a connection between the increase of vaccination site tumors and the rabies and FeLV vaccines.
Non vaccine-related fibrosarcomas can occur in cats of any age, but older cats are the more likely victims. The standard treatment in such cases is to attempt to surgically remove the tumor and a surrounding area of normal tissue...to make sure no cancer cells remain.
But this surgical approach is usually unsuccessful in the younger, healthier cats with vaccination site tumors due to the typical site of these tumors...between the shoulder blades.
When a tumor is against a bone, it's very difficult to surgically remove the whole tumor because you can't get a big enough margin around it. And if you leave even a single cancerous cell behind, the tumor will recur. Unfortunately, fibrosarcomas are notorious for recurring.
Investigators don't yet fully understand why some vaccines may cause vaccination site tumors in a small number of cats. Nor have investigators found a particular manufacturer's vaccine to be at fault.
Since relatively few cats are stricken, owners should continue to have their cats vaccinated ...with this proviso: find out what vaccines your cat really needs. The combined FVRCP vaccine, which protects cats against feline panleukopania, feline rhinotracheitis, and feline calicivirus, is both safe and effective.
All cats should get it...along with routine boosters. In most states, a rabies vaccination is mandatory. Whenever possible, request a 3 year rather than a 1 year rabies vaccine to lessen the chances of vaccination site tumors.
Unlike the rabies vaccine, the FeLV is a vaccine of choice. It is unnecessary if your cat is 100 percent indoors. Even if an indoor cat darts out momentarily, its chances of catching FeLV are low. An indoor/outdoor cat, on the other hand, is at greater risk and probably should be vaccinated.
Precautions to Take
Recognizing the concern of both veterinarians and cat owners, by November, 1996, the Vaccine Associated Feline Sarcoma Task Force was formed. The following are the recommendations made during those early investigations and subsequent ones.