The most commonly performed medical procedure for pet cats is annual immunization. For many years this has been a standard practice and recommendation. Over the last few years, new information has come to light that has caused us to question the validity of this recommendation. Research has shown that most cats can mount an immune response to vaccination that lasts longer than 12 months; in some instances vaccines have produced immunity lasting many years. As a result, many veterinarians have recommended vaccinating cats every 3 years rather than annually. But is this recommendation the best one? Is it possible that a better vaccine protocol would be more suitable for your cat? Does every cat even need any vaccines? This article will explore the topic of immunization and present a holistic alternative that has worked well in my practice.
While the recommendation for annual immunization has been the standard of practice for many years, there is really no scientific basis for it. Because there are potential short term and long term complications with vaccinations (see box,) and because it’s not good medical practice to do something that is of no real value and potential harm to our patients, researchers have investigated the value of increasing the time interval between vaccinations. Current recommendations are for most cats to be immunized every 3 years, although individual recommendations will vary based upon many factors (indoor versus outdoor cat, young cat versus older cat, etc.) While vaccinating every 3 years is preferable to vaccinating every year, I believe it’s better to try and determine what’s best for each individual cat rather than accepting a blanket recommendation for all of my feline patients. Therefore, in my practice I prefer the use of antibody (vaccine) titers to determine the need for vaccination.
These simple blood tests can give us information about an individual pet's antibody status in relation to specific diseases. In simple terms, antibodies are proteins made by the pet's white blood cells (specifically B lymphocytes.) These antibodies are made whenever a pet contacts an infectious organism (virus or bacteria, as a result of a natural infection) or is vaccinated (the vaccine uses low doses of infectious organisms, tricking the immune system to form protective antibodies without causing disease as might occur in a natural infection.) Using a titer test reveals each pet's antibody status. These results are then interpreted in an attempt to determine if the pet is currently protected against a specific infectious disease or if the pet may require immunization.
There are both pros and cons to the use of vaccine (antibody) titers to determine the need to immunize pets.
Pros:
- Easy to perform.
- Inexpensive (usually under $50.)
- Gives us specific information about each individual patient, allowing the doctor and owner to make a rational and informed decision.
- Replaces the current recommendation for vaccinating every pet regardless of actual need every 1-3 years.
Cons:
- While inexpensive, the extra cost may prohibit some owners from taking advantage of the testing.
- Some diseases will not be titered; rather, automatic immunization will still be given. This is the case for the rabies vaccine, which must be given following state law.
- Not all diseases produce a measurable titer. (For example, antibody levels have been shown to correlate with protection against feline panleukopenia virus but not with feline enteric coronavirus or feline chlamydial infection. Cellular immunity (rather than antibodies) provides protection against feline rhinotracheitis virus and feline infectious peritonitis virus, making titers inaccurate in interpreting protection for these diseases.) There is still adequate protection due to the cellular immunity the vaccines for these diseases produce.
- Titers, like vaccines, are not perfect. There is no guarantee that a pet with an adequate titer (or an annual vaccination) will not become infected or become ill with a disease. The titer only tells us that the pet should have adequate antibodies to fight off the infectious organism and that the pet possesses the ability to mount a secondary antibody response (and fight off the disease.)
- There is no agreed upon correct titer level for determining protective titers. Currently, doctors must use all of the conflicting information available and make an educated decision regarding what constitutes an "adequate, protective" titer. For feline panleukopenia, one suggested protective titer is >1:40, and this can be used as a rough guideline. (Currently, the use of titers is not perfect but gives us some information about each individual pet. Most holistic doctors will consider immunization if the pet fails to detect a titer of anywhere from >1:5, although some will use the upper end of the titers as mentioned above. The presence of any titer for those diseases in which titer information correlates with disease protection indicates the ability of the pet to respond to immunization and possibly infection. More research is needed to determine which vaccines induce the longest lasting protection, and how titer levels correlate with these specific vaccines.)