Cat Health General
Vaccinating Cats
Dr. Arnold Plotnick, D.V.M.
Vaccinations have probably done more to ensure the health of companion animals than any other advance in veterinary medicine. Veterinarians know that feline panleukopenia, canine distemper and other contagious infectious diseases have not gone away. They are always ready to reemerge.
Despite the many benefits of vaccinations, however, important questions have begun to come to light: Are veterinarians, as a profession, vaccinating too often? What about vaccine-induced tumors in cats, adverse vaccine reactions, and vaccines of limited or no value? There is no consensus on these issues.
In this issue of Animal Watch, we will look at feline vaccinations. "Vaccinating Fido in the 21st Century" will appear in the Summer 2000 issue.
YEARLY SHOTS
Annual vaccination for cats has long been the standard, but the recommendation was never based on scientifically validated studies. Over the past decade, both veterinarians and clients have begun to question the need for yearly boosters. Vaccine-associated tumors, in particular, have brought high visibility to the issue. Vaccination-site sarcomas (soft tissue tumors), associated more with some vaccines than with others (see "Lump Watch," below), dramatically illustrate that vaccination is not a benign procedure.
The American Association of Feline Practitioners (AAFP) and the Academy of Feline Medicine (AFM) Advisory Panel on Feline Vaccines have released a set of guidelines for feline vaccination in which they designate certain "core" vaccines. Because the diseases they immunize against are so serious and widespread, the core vaccines should be administered to all kittens and cats. The core vaccines are feline viral rhinotracheitis (FVR), feline calicivirus (FCV), feline panleukopenia (FPL) and rabies. Chlamydiosis, feline leukemia virus (FeLV), feline infectious peritonitis (FIP) and dermatophytosis (ringworm) are "non-core" vaccines and are recommended under some but not all circumstances. Since the release of the guidelines, feline Bordetella bronchiseptica has emerged as a respiratory pathogen of potential clinical significance. Whether or not a new vaccine against Bordatella bronchiseptica should be included with the core vaccines is controversial.
The ASPCA Bergh Memorial Animal Hospital recently adopted the position that it is not practical to recommend a single standard vaccination protocol for all cats. Instead, veterinarians should weigh each cat's risk of exposure to specific pathogens, the incidence and severity of disease, the efficacy and safety of available vaccines and client-specific requests and limitations. Our general recommendations for cats living in the New York metropolitan area are summarized in the table below, with the exact schedule to be tailored for each cat and owner.
LUMP WATCH
Epidemiological evidence shows a strong association between the administration of inactivated (killed) feline leukemia virus and rabies vaccines and subsequent soft tissue sarcoma development at vaccination sites. It is estimated that between 1 and 10 of every 10,000 of these vaccines result in vaccine-induced sarcoma. It is the individual veterinarian's responsibility to advise all cat owners of the risks of vaccine-induced sarcomas and instruct them to watch their cats for lumps.
Most post-vaccine lumps resolve in two to three months, and few vaccine-associated tumors occur sooner than three months after vaccination. Any lump at a vaccine site that is not gone by three months should be biopsied and examined by a pathologist. A biopsy will determine if surgery is needed and whether lumpectomy or radical surgery is indicated.
The mass should not be excised prior to biopsy. Attempts at simple excision of these tumors is seldom curative and ultimately leads to local recurrence with a more difficult second surgical attempt. These tumors are aggressive and difficult to manage. Even attempts at wide surgical excision often result in a 30 percent to 70 percent failure rate. These cases should be referred to a qualified surgeon before the second surgery. Clients who object to a biopsy procedure are encouraged to have a fine-needle aspirate and cytological examination performed.
More data are needed to pinpoint which vaccines are associated with local reactions or sarcomas. Accordingly, the AAFP and AFM recommend that veterinarians adhere to an anatomical "road map" when administering vaccinations. The Vaccine-Associated Sarcoma Task Force accepts the following sites:
- FVR/FCV/FPL: Administer subcutaneously (under the skin) over the right shoulder, as far down as practical.
- FeLV: Administer subcutaneously in the left rear leg ("left for leukemia"), as far down as practical.
- Rabies: Administer subcutaneously in the right rear leg ("right for rabies"), as far down as practical.
- Other: Administer over the left shoulder, as far down as possible. Avoid the area between the shoulder blades. Subcutaneous injections are preferred to the intramuscular route, as this permits earlier detection of post-vaccine lumps. Veterinarians should document the location of all vaccinations in the cat's record.
To not vaccinate is not an option. Our challenge is to come up with a vaccination strategy that maximizes our ability to prevent infectious disease while minimizing the concurrence of adverse events. We should regard vaccination as we do anesthesia: generally safe, with relatively rare adverse reactions and side effects. However, no veterinarian would recommend anesthesia without a valid indication for it, nor would he perform a surgical procedure simply because it was "generally safe." In short, our goal should be to vaccinate more animals, but less often.
However, moving away from annual vaccinations undoubtedly will mean that many pets will lose the benefit of a yearly exam. Thus it becomes even more important for pet owners to understand that a comprehensive physical exam should be performed at least annually and ideally every six months to assess their pet's health and amend vaccine recommendations, if necessary.
| CORE VACCINES |
| Disease/ Vaccine |
Feline Viral rhinotrachetus (FVR) |
Feline calicivirus (FCV) |
Feline panleukopenia (FPL) |
Rabies |
| Description |
Severe upper respiratory infection (URI); FVR and FCV account for 85 percent of all URI's in cats
|
Also called feline distemper, severe intestinal infection | Fatal infection that affects the central nervous system | |
| Highest Risk |
Kittens | Kittens | Kittens in shelters, multi-cat homes and urban stray populations. | All unvaccinated, warm-blooded animals, including humans |
| Initial Dose(s) |
6 weeks, 9 weeks, 12 weeks
|
12 weeks (kittens younger than 12 weeks are ineligible) | ||
| Boosters |
One year after initial vaccination,
then every 3 years |
One year after initial vaccination, then every 3 years (local law may mandate greater frequency) | ||
| Comment |
Kittens seen at 12 weeks of age need only one vaccine
|
1 to 3 per 10,000 cats develop sarcoma at the vaccination site; 3-year intervals advised | ||
| NON-CORE VACCINES |
| Disease/ Vaccine |
Feline leukemia virus (FeLV) |
Feline Infectious peritonitis (FIP) | Chlamydiosis | Dermatophytosis (ringworm) | Bordella bronchiseptica |
| Description | Profound immunosup-pression; may cause lymphosarcoma | Immune system disease that may affect many different tissues | Mild URI signs plus lateral, then bi-lateral conjuntivitis |
Fungal skin infection; highly contagious, including to humans |
Bacterial URI |
| Highest Risk |
Outdoor kittens under 16 weeks (85 percent of kittens under 12 weeks will become infected if exposed) |
Kittens and cats under 1 year of age in multi-cat environments | Cats in shelters and multi-cat environments | Very young and very old cats | Young kittens |
| Initial Dose(s) |
9 weeks and 12 weeks if at high risk | Intranasal vaccine at 12 weeks and 15 weeks if at high risk | Either 1 dose, regardless of age, or 2 doses, 3 weeks apart, in accordance with manufacturer's recommendations |
Three doses, according to manufacturer's recommendation | Not established |
| Boosters | One year after initial vaccination, then annually if under constant close exposure to infected cats | One year after initial vaccination, then annually if continued high risk | Annually | Not established | Not established |
| Comment | Highest association with sarcoma at site of vaccination; do not over-vaccinate | Efficacy of the FIP vaccine is controversial | Fewer than 5 percent of URI cases involve chlamydia; more adverse systemic reactions than with other common vaccines |
Vaccine does not eliminate fungus; use as part of total therapy in persistant, multi-cat situations |
Further studies needed |
Dr. Plotnick is vice president of animal health at Bergh Memorial Animal Hospital.
© 2000 ASPCA
ASPCA Animal Watch - Spring 2000
Courtesy of
ASPCA
424 East 92nd St.
New York, NY 10128-6804
(212) 876-7700
www.aspca.org
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