There are many diseases that are fatal to cats. Fortunately, we have the ability to prevent many of these by the use of very effective vaccines. In order to be effective, these vaccines must be given as a series of injections. Ideally, they are given at about 8, 12, and 16 weeks of age, but this schedule may vary somewhat depending on several factors.
The routine vaccination schedule will protect your kitten from five diseases: feline distemper, three respiratory organisms, and rabies. The first four are included in a combination vaccine that is given at 8, 12, and 16 weeks old. Rabies vaccine is given at 12 – 16 weeks of age. Leukemia vaccine is appropriate for any cat but a necessity if your cat does or will go outside or if you have another cat that goes in and out. This deadly disease is transmitted by contact with other cats, especially when fighting occurs. A vaccine is also available for protection against feline infectious peritonitis (FIP), an uncommon disease that is most likely to occur in groups of cats.
Why does my kitten need more than one vaccination for feline distemper, upper respiratory infections, and leukemia?
When the kitten nurses its mother, it receives a temporary form of immunity through its mother’s milk. This immunity is in the form of proteins called antibodies. For about 24-48 hours after birth, the kitten’s intestine allows absorption of these antibodies directly into the blood stream. This immunity is of benefit during the first few weeks of the kitten’s life, but, at some point, this immunity fails and the kitten must be able to make its own long-lasting immunity. Vaccinations are used for this purpose. As long as the mother’s antibodies are present, vaccinations do not “take” or provide protection. The mother’s antibodies will neutralize the vaccine so the vaccine does not get a chance to stimulate the kitten’s immune system.
Many factors determine when the kitten will be able to respond to vaccines. These include the level of immunity in the mother cat, how much of the antibody has been absorbed by the nursing kitten, and the number of vaccines the kitten receives. Since we do not know when an individual kitten will lose the short-term immunity, we give a series of vaccinations. We hope that at least two of these will fall in the window of time when the kitten has lost the immunity from its mother but has not yet been exposed to disease. A single vaccination, even if effective, is not likely to stimulate the long-term immunity, which is so important.
Rabies vaccine is an exception to this, since one injection given at the proper age and time is enough to produce long-term immunity.