Feline Vaccines

Why do we vaccinate?

According to the AAHA⁽¹⁾ Position Statement on Vaccine Issues⁽²⁾:"The vaccination needs of dogs and cats should be assessed at least yearly and, if appropriate, vaccination schedules should be modified on the basis of changes in the patient's age, health status, home and travel environment, and lifestyle. Vaccinations should be considered just one component of an individualized, comprehensive preventive health-care plan based on the age, breed, health status, environment (potential exposure to harmful agents), lifestyle (contact with other animals), and travel habits of the dog or cat. We at HPVS believe whole-heartedly in this. Over-vaccination may be just as dangerous as not vaccinating, so getting the right balance is important.

Rabies

Rabies is a preventable viral disease of mammals most often transmitted through the bite of a rabid animal. The rabies virus infects the central nervous system and once clinical signs appear is almost always fatal. All known mammals are possible carriers of rabies, however small mammals such as mice and squirrels are rarely ever found to carry the disease. In Florida Raccoons are the most common carrier of rabies with foxes and bats coming in second. Cats are the most common domestic animal to test positive for rabies (62.2% of domestic cases in 2010)⁽³⁾.

Because of the link between vaccines and feline fibrosarcomas (cancer), guidelines for cats are a little different than for dogs. The AAFP (American Association of Feline Practitioners) Vaccine Advisory Panel⁽²⁾ "suggests that veterinarians use less inflammatory products whenever possible." In the case of the rabies virus vaccine the least inflammatory is a non-adjuvanted Canarypox virus-vectored recombinant (rRabies) made by Merial. The Purevax Rabies is currently only labeled as a one year vaccine, though we are hoping they will have the research in the near future to get a three year label.

As an aside AAHA Guidelines for dogs, cats, and ferrets recommend that "a single dose of a "3-yr" rabies vaccine be administered within 1 yr after administration of the initial dose, regardless of the animal's age at the time the initial dose was administered. Subsequently, revaccination with a "3-yr rabies" vaccine should be administered every 3 yr thereafter."

FL Statute 828.30(1)"All dogs, cats, and ferrets 4 months of age or older must be vaccinated by a licensed veterinarian against rabies with a vaccine that is licensed by the United States Department of Agriculture for use in those species. The owner of every dog, cat, and ferret shall have the animal revaccinated 12 months after the initial vaccination. Thereafter, the interval between vaccinations shall conform to the vaccine manufacturer's directions. The cost of vaccination must be borne by the animal's owner. Evidence of circulating rabies virus neutralizing antibodies shall not be used as a substitute for current vaccination in managing rabies exposure or determining the need for booster vaccinations."

FVRCP

FVR=Feline Viral Rhinotracheitis is caused by feline herpesvirus-1. It is a highly contagious upper respiratory disease of cats that can lead to pneumonia and ulcers in the eyes. Young kittens and older or sick cats are much more susceptible and have a higher mortality rate. Cats that are infected with the herpes virus are considered lifetime carriers and may show clinical signs of the disease during times of stress. Some cats that have severe infections may have permanant damage to their eyes or respiratory tract.

Unfortunately the way the disease enters and acts on the body makes the current vaccines available unable to prevent infection and shedding of virus, but they do greatly reduce local disease and protect vaccinated cats against serious systemic disease⁽⁴⁾.

C=Calicivirus is also a highly contagious respiratory disease in cats. There are numerous strains of this virus and they cause anything from mild sneezing to severe pneumonia and rapid death in young kittens and old cats. Common signs of this virus are very similar to the herpes virus but can also include severe conjunctivitis (pink eye). Permanant damage and reoccuring clinical signs are also a possibility. Vaccination also does not prevent infection or shedding of this disease, but significantly reduces or eliminates clinical signs associated with it.

P=Parvovirus (also known as Panleukopenia, Feline Distemper, and Feline infectious enteritis) is a highly contagious disease in cats that results in severe suppression of all types of white blood cells (panleukopenia) GI signs such as vomiting and diarrhea, high fever, and sudden death. Mortality rate may reach up to 90% in kittens under 6 months of age and may be as high as 50% in unprotected adult cats. It is shed mainly in the feces of infected cats, but the virus can remain in the environment for months to years. The vaccine is highly effective in producing complete immunity to this disease.

AAFP Guidelines recommend "Vaccines should be administered at intervals of 3 to 4 weeks until kittens are 16 weeks old starting at 8 to 9 weeks of age. The minimum vaccination interval during the primary series is 2 weeks, and the maximum recommended interval is 4 weeks. Kittens presented for booster vaccination 6 weeks or longer following administration of the previous dose of vaccine should receive at least 2 doses of vaccine, 3 to 4 weeks apart." Adult cats with unknown vaccine history should recieve two doses 2-4 weeks apart. The vaccine should be boostered in one year and then every three years thereafter.

FeLV (Feline Leukemia Virus)

FeLV is a retrovirus that is a widespread disease in cats. It is present in about 5% of all cats in the USA⁽⁵⁾ making it one of the most common life-threatening disease in cats. The virus is spread through contact with infected saliva, blood, or from mother to kitten. Many cats will develop immunity to it, but in the ones that do not, the virus spread to the bone marrow causing immunosuppression and can lead to leukemia or lymphoma. Some cats can be carriers and show a negative test, but are spreading the virus through their body fluids and may become clinically ill from the diseaes in time of stress. Average lifespan of a FeLV positive cat is less than three years. They often die from other diseases due to the immunosuppression caused by the virus.

AAFP guidelines recommend that all kittens should be vaccinated for FeLV even when the cat is intended to be a totally indoor cat. The highest susceptibility to infection occurs in cats under one year of age⁽⁶⁾. All cats that have direct contact with cats of known positive or uncertain status, such as outdoor cats should also be vaccinated. Adult cats that are confined to a screen porch do not need vaccination.

As an aside all new cats should be tested for FeLV before being introduced into a new household and then retested based on their age in 3 to 6 months. Any sick cat that has even had a chance of exposure to the virus should be tested again as well. The virus is very fragile outside the cat's body and almost all common household cleaners will kill the virus.

FIV (Feline Immunodeficiency Virus)

FIV is a lentivirus that is most commonly seen in adult male cats that spend time outdoors. The virus is mainly spread through bite wounds from an infected cat. Cats may remain clinically unaffected for months to years, but the FIV is slowly causing degredation of the immune systom and eventually leads to immunosuppression and higher rate of infections and cancers. Infected cats can cohabitate with FIV negative cats as long as they are minimally aggressive since general contact, including sharing a food bowl and mutual grooming is not enough to transmit the disease.

The FIV vaccine is not considered a core vaccine by the AAFP. Consider FIV Vaccination in cats living with FIV-positive cats, particularly if there is fighting and in cats that go outside and fight or are attacked. Cats vaccinated with the current FIV vaccine will test positive for FIV antibodies. A visible (collar) and permanent (microchip) identification is strongly recommended for cats vaccinated against FIV since a positive test in an animal shelter may result in rapid euthanasia.

Possible Side Effects of Vaccines

Side effects most commonly observed include: reduced or loss of appetite (lasting for one or two feedings), pain at the injection site (possibly mild limping), lethargy (lack of activity), reluctance to walk and/or run, and mild fever. Treatment is usually not indicated and it is essential to NEVER give cats aspirin, tylenol, Advil, Alieve or other anti-inflammatories that you would take for a fever. Even a single dose of these medications could prove fatal to your cat. Hives, swelling of the face, vomiting, and diarrhea are signs of a slightly more severe reaction that usually requires treatment with an antihistamine +/- a steroid for a few days. An anaphylactic reaction is a medical emergency. Signs include sudden collapse, difficulty breathing, paleness of gums, sever swelling around head and neck. If you see any of these signs contact your vet immediately. There are a few very rare conditions associated with vaccinations that can occur a few weeks after administration. In using the non-adjuvanted, recombinate virus vaccines versus the whole killed virus vaccines we are significantly reducing the risk of a vaccine associated reaction. Not all vaccines are created equal.

Cats also have a unique complication of vaccine induced tumors called fibrosarcomas. The chance of a vaccine induced tumor is higher with the killed whole virus rabies and FeLV vaccines. It occurs at a rate of about 1 tumor per 10,000 vaccine doses given. While this risk is small it doesn't help if your cat is the one to get the tumor. The AAFP recommends cats be vaccinated low on their extremities (over the knee and near the elbow) so if a tumor appears the limb can be amputated to cure the cancer. While this sounds like a drastic and horrible approach, a cat developing a fibrosarcoma between his shoulder blades has no chance of being cured.

References

1. AAHA Position Statement on Vaccine Issues
2. The 2006 American Association of Feline Practitioners Feline Vaccine Advisory Panel Report
3. "Rabies surveillance in the United States during 2010" Jesse D. Blanton, mph; Dustyn Palmer, ba; Jessie Dyer, msph; Charles E. Rupprecht, vmd, phd
4. Povey RC, Koones H, Hays MB. Immunogenicity and safety of an inactivated vaccine for the prevention of rhinotracheitis, caliciviral disease, and panleukopenia in cats. J Am Vet Med Assoc 1980;177:347-350.
5. Levy JK, Scott HM, Lachtara JL, et al. Seroprevalence of feline leukemia virus and feline immunodeficiency virus infection among cats in North America and risk factors for seropositivity. J Am Vet Med Assoc 2006;228:371-376.
6. Hoover EA, Olsen RG, Hardy WD Jr, et al. Feline leukemia virus infection: age-related variation in response of cats to experimental infection. J Natl Cancer Inst 1976;57:365-369.