Prior to 2003, veterinarians turned to a variety of sources to decide how often to vaccinate their canine patients. Since then, thanks to the work of experts in immunity, infectious diseases and internal medicine, they have been able to look to a set of guidelines, most recently updated just last year and published in the September-October 2011 issue of the Journal of the American Animal Hospital Association.
Ronald D. Schultz, Ph.D., of the University of Wisconsin School of Veterinary Medicine Department of Pathobiological Sciences has been part of the collaborative effort to develop and update the guidelines from their beginnings. But he’s studied vaccines, their effectiveness and longevity since the 1970s.
As his work, then done at Cornell University with other researchers, was demonstrating how long the immunity from vaccines lasts, “The need to really get some standardization of vaccination programs” became clear, he says. “We needed to put more science into the practice of vaccination,” he says.
He recalls that it was the American Association of Feline Practitioners that first decided, in 1998, to put guidelines together for cats, so practitioners would “better appreciate when to do it, how to do it, what vaccines to use and what the potential effects of over-vaccination could be.”.
Today, the American Animal Hospital Association facilitates the updating of the standards, now known as the “AAHA Canine Vaccination Guidelines.” The American Veterinary Medical Association, which formerly had a committee to gather experts who drafted recommendations, “pretty much now endorses” the guidelines, Schultz says. “They felt that this was a good way to go – that those experts in vaccines and immunology with an interest in specific species should probably make the guidelines available.”
The 2011 guidelines continue to emphasize that all puppies should have an initial vaccination series to protect them from distemper, parvovirus, hepatitis and adenovirus, between the ages of 6 and 16 weeks, with each dose administered three to four weeks apart. The final dose must be given after 14 weeks of age “to minimize the risk of maternal antibody interference,” the guidelines state. If the last shot is given any earlier, the puppy may not develop immunity to one or more of the viruses.
In addition, a rabies vaccination should be administered no earlier than 12 weeks of age. While a three-year vaccine can be used, the puppy will still need another dose one year later. At that time, a three-year vaccine may be used, depending on the jurisdiction in which it lives. Some cities and counties still require an annual rabies vaccination, but most accept a three-year vaccination.
Those four vaccines (CAV-2 creates immunity to both hepatitis and adenovirus) are considered “core,” meaning that every healthy dog should be vaccinated to prevent those viruses.
Numerous other vaccines, such as those for leptospirosis, bordetella, parainfluenza and Lyme disease are “noncore.” Only in dogs that live in areas with disease prevalence is the vaccine recommended. If any of these is an issue for your dogs, annual vaccination is needed. In addition, the Lyme disease vaccine does not eliminate the need to use tick prevention products on your dogs, according to the guidelines.
Falling into the “not recommended” vaccine category are:
- • MV, sometimes used for temporary immunization against distemper;
- • Leptospira interrogans 2-way; the 4-way is recommended if a dog is in danger of exposure; and
- • Coronavirus, because it doesn’t significantly reduce disease.
Although all vaccinations were given annually for many years in the 1970s through the 1990s, the guidelines recommend repeating core vaccines no more often than every three years.
However, Schultz’s work and that of other researchers has shown that immunity can last for many years, depending on the virus.
Because of this, many dog owners have turned to blood tests to determine whether their dog needs a booster vaccine for a particular virus. While this can be expensive, it is not an uncommon practice. The 2011 guidelines include updated recommendations on serologic testing.
“Antibody assays for CDV [distemper] and CPV-2 [parvovirus] – the two tests performed most often – are the tests of greatest benefit in monitoring immunity, especially after the puppy vaccination series,” reads the serologic section of the guidelines. Schultz supports testing puppies after the series to ensure that appropriate antibodies have been developed. Otherwise, you may think your dog is protected, when, in fact, it isn’t. If it doesn’t have necessary antibodies, it can be revaccinated. Although rare, some puppies will never respond to a parvovirus or distemper vaccine.
Antibody tests can also be used to show that a dog is still protected from disease due to vaccines or natural immunization – from exposure or maternal antibodies. Several studies have shown that “antibodies to the core vaccine viruses might persist in the absence of revaccination for many years. All of the major vaccine manufacturers have products that were shown to provide a minimum [duration of immunity] of three years.”
The section concludes that “antibody-negative dogs should be revaccinated. Similarly, dogs that have been actively immunized by vaccination or naturally by infection that have antibodies to CDV, CPV-2, or CAV-1 do not need to be revaccinated.”
However, testing for antibodies from other vaccines, such as leptospirosis or Lyme, is not helpful in deciding whether to revaccinate “because the antibody may persist for a short time or there is no known correlation between serum antibody tests routinely performed and protection.”
The 2011 version of the guidelines also have a new FAQs section to answer common questions asked by practicing veterinarians, such as “Is it safe to inject different vaccines (not part of a single commercial product) into the same dog at the same appointment?” and “Should the large dog (e.g., Great Dane) be injected with the same volume of vaccine as the small dog (e.g., Chihuahua)?” The answer to the first question is “yes,” as long as the second vaccine is injected in a different spot. The second answer is also “yes,” as all dogs should get the same amount of vaccine regardless of size.
According to the introduction to the guidelines, they are “recommendations” and “should not be construed as dictating an exclusive protocol, course of treatment or procedure. Variations in practice may be warranted based on the needs of the individual patient, resources, and limitations unique to each individual practice setting.”
Schultz says veterinarians’ adoption of the guidelines, and even the concept that each dog’s needs should be considered before deciding on a vaccination protocol, runs the gamut.
“It varies widely as on any medical topic, on their interest and knowledge on the topic. I think in 2012, there are still practitioners who are doing what they did in 1970 or 1980 or 1990, whenever they got into practice. They probably haven’t changed very much.
“The guidelines are there, and that’s exactly what they are. There’s no mandate for them to follow them.
“In other cases, there are practitioners who have been out there since the ‘70s or ‘80s that have embraced the guidelines and completely changed their programs.”
He adds, however, that even newly graduated veterinarians who go into long-established practices may find that they have to follow what’s being done at that practice unless they can convince the practice owner otherwise.
“It’s all over the board. Some feel the guidelines recommend too many vaccines and too often. Some are just anti-vaccines.”
Another misperception of the guidelines over the years is that the task force went from recommending annual boosters to triennial boosters. Schultz points out that the guidelines never said that boosters should be given every three years. They have always said to wait “at least” three years between boosters.
To see the current guidelines, click here.