TO VACCINATE OR NOT TO VACCINATE: THAT IS THE QUESTION

Many feline guardians make the annual trip to their trusted veterinarian to get their cats vaccinated against common infectious diseases. It is rarely a comfortable outing for the cats or the guardian. Trying to get your cat into her carrier can be a harrowing experience, and lately people have begun asking themselves: If my cat doesn’t go outside, do I really need to put her through all this each year?

In the past, the answer to this question has always been that it’s better to be safe than sorry. However, recent studies have shown that it may not be necessary to vaccinate cats for every possible disease, and that there may even be a risk involved with vaccinating your companion animals too often.

Soft tissue sarcomas are a form of cancer that develop on the skin. These sarcomas are not something new, and they are seldom caused by the injection of a vaccine, but in the past decade, many veterinarians have reported an increase in sarcoma masses found on cats, oftentimes at the point where a vaccination needle enters the body.

Is this cause for alarm? Not necessarily, but it has brought attention from the veterinary community, and it has made people re-evaluate the issue of annual vaccinations for their cats. In response to this, a group of organizations joined together to form the Vaccine-Associated Feline Sarcoma Task Force (VAFSTF). The VAFSTF was created in 1996, and it is a coalition of national veterinary organizations dedicated to resolving this dilemma. The group is devoting considerable human and financial resources to determine the true scope of the problem, the cause, and the most effective treatment of vaccine-associated sarcomas.

The Task Force also provides insight and information to this emerging issue in feline healthcare. Dr. James R. Richards, one of the leaders of the Task Force, is the Director of the Cornell Feline Health Center at Cornell University. Tree House had the opportunity to speak with him about this important issue, and we asked some questions that might shed light on the subject of vaccine-associated sarcoma.

How common is vaccine-associated sarcoma? Does the Task Force think the occurrence is increasing, or just the recognition and reporting of the condition? 

Based on the information we receive from veterinarian offices across the country, we estimate that vaccine-associated sarcoma occurs 1 to 4 times in every 10,000 cats vaccinated. Because there is no registry in veterinary medicine, we can only estimate the frequency of occurrence of this form of cancer. We believe that this does not reflect an increase in sarcomas, just an increase in recognition and identification.

Is there any way to prevent sarcomas during vaccination?

 Not at this time. We believe that the genetic background of a cat predisposes him or her to sarcomas. There is no way to recognize which cats are more inclined to be afflicted, but sarcomas might manifest in some other manner if not through a vaccine-associated sarcoma. Feline guardians should evaluate the lifestyle of their cat and vaccinate only as necessary. If a cat should happen to be predisposed to sarcomas, it is always beneficial to reduce the chances of exposure to this disease as much as possible.

 What are the symptoms of vaccine-associated sarcoma? Can it be caught in the early stages to minimize the health risk to the cat?

 Early detection is the key, and it will result in a much better chance for recovery. If you take your cat to be vaccinated, be sure to monitor the vaccine point to ensure that your cat is reacting normally. Some things to look for initially are:

- discomfort at the site where the vaccine was given

- mild fever

- diminished appetite and activity

- sneezing at about four to seven days after administration of an intranasal vaccine

- development of a small, firm, non-painful swelling under the skin at the site where the vaccine was given. The swelling usually goes away after several weeks, but if you notice such a swelling, you should contact your veterinarian.

- a serious and potentially life-threatening allergic reaction within several minutes to an hour after vaccination.

The Task Force has developed a set of three principles which act as warning signs for concerned feline guardians:

• If the lump is increasing in size (1) month later.
• If the lump is over (2) centimeters (about the size of an olive).
• If the lump is present (3) months after the vaccination.

If any one of these situations occurs, have your veterinarian take a biopsy of the lump to identify its nature.

 If my cat is diagnosed with a sarcoma, what steps can be taken to treat this type of cancer?

 Surgery is the most successful form of treatment. If a biopsy confirms the sarcoma, your veterinarian may refer you to a veterinary oncologist or a veterinary surgical specialist. The removal of all of the tissue around the sarcoma seems to have better results than radiation therapy or chemotherapy. Unfortunately, sarcomas are an aggressive form of cancer, and they can often reappear quickly if any of the affected tissue remains in the body.

 If my cat never goes outside, what types of vaccines are recommended?

 The choice of which vaccines your cat should receive is dependent on a number of factors including:

1) Your cat's risk of exposure to the disease-causing organism (in part dependent on the health of other cats to which yours is exposed, and the environment in which your cat lives).

2) The risk an infected cat poses to human health (e. g., rabies).

3) The protective ability of the vaccine.

4) The frequency or severity of reactions the vaccine produces.

5) The age and health status of your cat.

6) Vaccine reactions your cat may have experienced in the past.

Your veterinarian can help guide you in deciding which vaccines are appropriate for your cat.

 Does my cat need to be vaccinated every year?

The answer depends upon the vaccine. Certain feline rabies vaccines provide protection for longer than one year, so vaccination with a triennially-approved rabies vaccine every three years (after the initial series is completed, and when consistent with local rabies vaccine requirements) is sufficient. Recent research has provided compelling evidence to suggest that panleukopenia/rhinotracheitis/calicivirus vaccines provide adequate protection for several years, so in response, many veterinarians are now recommending that this vaccine be "boosted" at three year intervals as well. Unfortunately, far less is known about the duration of protection provided by other vaccines. Until that information is known, annual vaccination with those products is a reasonable course of action.

 Are vaccines dangerous?

 Not usually. Unfortunately, a perfect, risk-free vaccine does not exist. Without question, vaccines have saved countless lives, and they continue to be indispensable weapons in the battle against feline infectious disease. But as with any medical procedure, there is a small chance that reactions may develop as a result of vaccination. In most cases, the risks associated with vaccination are much smaller than the risks of disease if vaccines were not given. But to minimize the risk, before your cat is vaccinated, please inform your veterinarian of any problems your cat is experiencing or any medication your cat is receiving.

 SIDEBAR

The following vaccines are currently available:

Feline Panleukopenia Virus Vaccine: Feline panleukopenia (also called feline distemper) is a highly contagious and deadly viral disease of cats. Feline panleukopenia virus is extremely hardy, is able to survive extremes of temperature and humidity for many months, and is resistant to most available disinfectants. Until recent years, panleukopenia was the most serious infectious disease of cats, claiming the lives of thousands every year. Thanks to the highly effective vaccines currently available, panleukopenia is now considered to be an uncommon disease. However, because of the serious nature of the disease and the continued presence of virus in the environment, vaccination is highly recommended for all cats.

Feline Calicivirus/Herpesvirus Vaccine: Feline calicivirus and feline herpes virus type I are responsible for 80-90% of infectious feline upper respiratory tract diseases. Most cats are exposed to either or both of these viruses at some time in their lives. Once infected, many cats never completely rid themselves of the virus. These "carrier" cats either continuously or intermittently shed the organisms for long periods of time -- perhaps for life -- and serve as a major source of infection to other cats. The currently available vaccines will minimize the severity of upper respiratory infections, although none will prevent disease in all situations. Vaccination is highly recommended for all cats.

Rabies Virus Vaccine: Rabies is an increasing threat to cats. At the present time, the number of reported feline rabies cases in the United States far exceeds that of all other domestic animals. Rabies in cats is also a major public health concern. Because of the routinely fatal outcome of infection in cats, and the potential for human exposure, rabies vaccination is highly recommended for all cats; it is required by law in most areas of the country.

Feline Leukemia Virus Vaccine: Feline leukemia virus (FeLV) is the leading viral killer of cats. The virus is spread from cat-to-cat through bite wounds, through casual contact with infected cats, and from an infected mother cat to her kittens. The individuals most at risk of infection are outdoor cats, indoor/outdoor cats, and cats exposed to such individuals. Cats living in households with FeLV-infected cats or with cats of unknown infection status are also at risk. Indoor-only cats with no exposure to potentially infected cats are extremely unlikely to become infected. FeLV vaccines are recommended for all cats at risk of exposure to the virus.

Chlamydia, Feline Infectious Peritonitis, and Ringworm Vaccines : Vaccines are available for each of these disease-causing organisms, but their use is not routinely recommended for all cats. Your veterinarian will help guide you in deciding whether your cat should receive any of these vaccines.