There has been justifiable concern over the last two decades that some cats appear to develop a cancerous mass, called a sarcoma, after being vaccinated. In most cases these sarcomas appear months or years after the vaccine.
Enough aggressively invasive cancers were seen that it caused a shift in not only where we choose to vaccinate but also in the vaccines we recommended.
The veterinary profession used to, in general, just vaccinate everyone the same based on the same cookie-cutter recipe we had used for years. There wasn't a discussion with owners over what individual needs a pet might have or how their lifestyle might influence their vaccine needs.
The first few cases of feline sarcomas opened the door to change our way of thinking and delivering vaccines.
These sarcomas, when seen are very invasive to the tissue, are difficult to remove, and almost impossible to remove adequately to stop recurrence. When found, and elected to treat, these cases often need to be referred to a surgical specialist to not only remove, but also to an oncologist to follow up with. In our practice we have had very limited success with treating them. The tumors ability to penetrate deep into tissue and the lean body structure of cats usually proves too difficult for us to surgically remove completely.
Because of the terrible prognosis these tumors present, and the difficulty in treating them, most veterinarians now discuss the pets lifestyle and environmental needs before we just pull up the shots and deliver them.
The vaccine that has been affiliated with the greatest number of sarcomas is the feline leukemia vaccine. For every appointment that I have with a client I discuss what environment their cat lives in and we also discuss any possible exposures. If my client has an inside only, or even predominantly inside, cat then we usually elect to skip this vaccine.
Many vets have also switched to 3 year vaccines instead of the yearly boosters. Scientific studies have shown that these 3 year vaccines provide at least three years of duration of immunity to cats. This has significantly reduced the number of vaccines a pet gets, and hopefully reduces the likelihood of them getting a sarcoma.
Unfortunately, I know of some veterinary practices who have not switched to 3 year vaccines because they don't want to lose a yearly examination and shot opportunity. We vets know that many cat households will not bring their pet in for an examination if there isn't a shot needed. Now I would argue that the greatest value to your pet is the physical examination. I know that shots are very important to the young growing pets, and as I have just stated, we don't want to over vaccinate anyone, but those young pets are so susceptible to preventable diseases that vaccinating saves many kittens lives. If your vet is vaccinating yearly please ask them why? If you are still concerned about over vaccination, ask your vet if they can give your cat a 3 year vaccine? Or ask another veterinarian in your area if they also give yearly vaccines. I firmly believe that the only right vaccine protocol is the one safest for your pet.
It is also very important to mention that annual or semi-annual exams save lives. We often find early treatable diseases, and are able to intervene to either slow down its course or alter it completely.
When vaccinating we used to always use the area between the shoulder blades to give our sq shots. There is ample amount of skin, and it is an easy and effective place to "scruff" and hold a cat. Now we try to deliver the shots as low on a limb as possible. The theory is that if we do encounter a tumor in the future that we can remove the tumor by removing the limb if needed. When the best possible outcome is surgical removal to achieve clean tumor free margins the loss of a limb is sometimes the best option we have.