In a society becoming increasingly naturally minded, it should come as no surprise that this trend also applies to people’s pets. I have blogged quite a bit about alternative medicine techniques that carry no side effect but offer proven benefits to dogs and cats, and the popularity of these techniques and how mainstream they have become in my practice, as a testament to how much people are choosing a more natural existence for their pets as well. Knowing that immunizations, while necessary components to canine and feline disease prevention, can stress the body in the short term and have been linked to rare problems later in life, pet owners began to really question the necessity of the frequency by which veterinarians were vaccinating their pets.
Thankfully, the industry responded, and though extensive research in the early 2000s, the American Veterinary Medical Association established reformed vaccination protocols that led to less frequent vaccinations for core vaccines that offered longer protection than previously known; while being more discerning with the administration of non-core vaccines with regard to the individual patient’s actual risk factors (lifestyle, geographical location, breed, etc.). For example, rather than give the core canine distemper-parvo-hepatitis-parainfluenza (DHPP) vaccine and the core feline panleukopenia-calicivirus-herpes virus (FVRCP) once yearly for dogs and cats, respectively, we began administering these vaccines once every 3 years. For the non-core vaccines, leptospirosis, lyme, bordatella for dogs, and feline leukemia for cats, these vaccines have been tailored to the patient’s individual lifestyle and disease risk, which vary not just from patient to patient, but from one region to another.
With regard to the core rabies vaccine, the 3 year vaccine is effective, safe and approved for dogs in all jurisdictions I am aware of (from legal standpoint) for both dogs and cats, but given a past speculated link of the 3 year rabies vaccine to risk of malignant tumor formation in cats, many veterinarians advise the one year rabies Purvax manufactured by the veterinary pharmaceutical Merial. Although this link has largely been disproven, with so many feline owners remaining concerned about the link nonetheless, many veterinarians continue to use the 1 year rabies Purvax in cats.
Now that all the background of vaccine reform history in the past decade has been established, I will move on to the topic at hand: antibody titers. An antibody titer is a measure of protective antibody generated in the body from vaccines that mimic the disease (while not themselves causing disease), or from having survived a bout of the actual disease and generated antibodies to it. Antibodies are markers that attach to a bacterial or viral foreign invader and target it for removal by immune system cells.
Learning that measurement of protective antibody titers was one of the components of the research that led to vaccine reform, the establishment’s reform for some pet owners have not taken things far enough for their desire to have their pets live as naturally as possible. As a result, in lieu of getting vaccines for their pets per our latest reform guidelines, they instead demand that their pet first have blood titers checked to determine whether or not vaccination is necessary.
The flaw in relying on titers is that, as I stated, titers are only one small component of vaccine efficacy research. Realistically, the immune system is so complex, that titers are not reliable for every individual and for every disease, as has been proven time and again in research settings where protective titers did not hold up against a challenge to a given disease. Remember that antibodies target the foreign invaders for destruction, but it is other immune system cells that actually destroy the invader. An insufficiency in this process may leave a pet at risk for a given disease even if protective antibody titers are present. Therefore, protective titers are really in the end little more than an approximation of a pet’s immunity to a given disease.
The story, however, does not end there. In the case of the three major and life threatening diseases vaccinated for in the canine core DHPP vaccine (distemper, parvo, and hepatitis), antibody titer does seem to correlate well with adequate protection against disease. Therefore, if owners wish to rely on titers to decide on whether or not their dog needs to be vaccinated, if they do not mind the increased expense of titer testing rather than just vaccinating, I support that decision. Unfortunately, for rabies and the non-core vaccines, titers not proven even nearly as reliable in determining individual disease protection. This is why in the case of rabies, any jurisdiction I am aware of will not accept proof of protective rabies antibodies as an alternative to a rabies vaccine for dogs and cats. Thus in the case of canine non-core vaccines and rabies, I do not advise reliance on antibody titer testing…nor is it even legal to do so for rabies anyway.
For cat owners that favor the idea of relying on antibody titer testing, the story is a bit more discouraging. For cats, titers for both core and non-core vaccines do not seem to correlate with protection from disease. As such, at this time and given the current vaccine technology, titer measurement in cats is not a good assessment of the necessity for vaccination. Thus, I would not advise any feline owner to rely on vaccine titers, but instead simply follow AVMA recommended vaccine protocols.