n Current Veterinary Therapy XI in 1992 (This is a purely conventional textbook, and Drs. Schultz and Phillips are respected veterinary immunologists in the academic community):
A practice that was started many years ago and that lacks scientific validity or verification is annual revaccinations. Almost without exception there is no immunologic requirement for annual revaccination. Immunity to viruses persists for years or for the life of the animal. Successful vaccination to most bacterial pathogens produces an immunologic memory that remains for years, allowing an animal to develop a protective anamnestic (secondary) response when exposed to virulent organisms.
Only the immune response to toxins requires boosters (e.g. tetanus toxin booster, in humans, is recommended once every 7-10 years), and no toxin vaccines are currently used for dogs and cats. Furthermore, revaccination with most viral vaccines fails to stimulate an anamnestic (secondary) response as a result of interference by existing antibody (similar to maternal antibody interference).
The practice of annual vaccination in our opinion should be considered of questionable efficacy unless it is used as a mechanism to provide an annual physical examination or is required by law (i.e., certain states require annual revaccination for rabies). (Italics added) In essence, Drs. Schultz and Phillips are stating that the only reasons for annual vaccination are legal (as with rabies vaccination) or as a means of manipulating guardians into bringing their companions for examinations (rather than simply recommending an examination). They also clearly state that booster vaccines provide no other benefit, including improved or added immunization.
Although it has been some years since this was published, the veterinary community has made little headway toward following these recommendations. Some university experts now recommend vaccinations every three years, and other university clinics recommend titer testing to determine need. While both concepts are a step in the right direction, they still do not reflect the actual picture.
As the above quote indicates, immunologic memory lasts for years (usually for the life of the individual). This memory is not dependent upon titers, nor do titer levels always accurately indicate the immune status. A titer is a reflection of the quantity of circulating antibodies (immunoglobulins) to a given antigen (in this case, an organism). Cells in the body produce the antibody. These cells retain the ability to produce antibodies toward a given antigen for quite a long time, usually for life.
Upon re-exposure, they can produce antibody within forty-eight hours. As a consequence of this capability, there is no need for the body to expend the energy needed to maintain circulating antibodies. A low or absent titer, therefore, does not mean the body is unprotected. The body may simply have cells ready to act, like firefighters playing cards until they are needed. When booster vaccines are administered, antibodies destroy the vaccine particles before they can augment the immunity, and nothing is accomplished.
With kittens, antibodies (maternal antibody) may be passed from the mother to the kittens via the umbilical cord and via colostrum (the first milk). This antibody serves to protect the kitten, but it also can interfere with vaccination. For this reason, we often vaccinate kittens multiple times, in hopes that we will give a vaccination shortly after the maternal antibody diminishes to a level that will not interfere with vaccination. This is often overkill, as one vaccination can induce immunity in approximately 95 percent of animals if the timing is correct.
Multiple vaccination, particularly with combination vaccines, is one of the greatest contributors to vaccine-induced illness. Limiting vaccination to one or two doses of appropriately indicated vaccines could greatly reduce disease from vaccination. In my opinion, this would be a huge step in the right direction for those who are too fearful to avoid vaccines entirely.
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