In the September, 2006 issue of "Your Dog", the Newsletter of The Cummings School of Veterinary Medicine at Tufts University, an article in the "Cutting Edge" section addressed new recommendations endorsed by the AVMA for canine vaccination schedules. The full article by Amy D. Shojai appears below, courtesy of "Your Dog" (http://www.tufts.edu/vet/publications/yourdog/). We encourage you to read it and discuss the recommendations with your veterinarian.

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Cutting Edge

Annual Boosters Are
No Longer Needed

New research verifies the main
vaccines’ three-year immunity

Not every dog needs every shot every year.

Owners and veterinarians should decide on vaccinations based on lifestyle and incidence of disease in their area.

The guidelines are changing how veterinarians practice medicine.

By Amy D. Shojai

Pepper suffered a severe vaccine reaction last year. The Miniature Schnauzer began breathing rapidly, her face swelled and hives covered her torso until the welts raised her fur in splotches. “It happened an hour after she received the seven-in-one shot at the vet,” said owner Linda Backus of Little Hocking, Ohio.
Luckily, Pepper recovered. When a second dog, Nikki, suffered a similar reaction after receiving the injection combining seven vaccines, Backus decided to vaccinate more selectively and less frequently. “I love my veterinarian,” she said, “but when it comes time for more shots, I find a veterinarian who does not give the seven-in-one.”
Adverse reactions are the No. 1 reason experts recommended changes – principally fewer annual booster shots – to guidelines from the American Animal Hospital Association.

Evaluate Risks
Veterinarians used to routinely give dogs annual booster vaccinations, based on the science at the time. Today research shows that not every dog needs every shot every year. Instead, their owners and veterinarians should decide on appropriate vaccinations based on individual need and evaluation of risk, such as canine lifestyle and incidence of a given disease in their area. Previous guidelines, released in 2003, had suggested switching revaccination from yearly to every three years. New research strongly supports that view.
“The most significant change in the guidelines is the duration of immunity has now been verified for at least three years for the main vaccines -- distemper, canine adenovirus-2 (hepatitis) and parvovirus,” said oncologist Susan Cotter, DVM, Distinguished Professor at the Cummings School of Veterinary Medicine at Tufts University. “The main difference is in the assurance that the three-year recommendation is based on good evidence.”
Dr. Cotter served on the Canine Vaccine Task Force that revised the guidelines. The international group included practitioners, internists, infectious disease experts and immunologists. Among their other important recommendations, said Dr. Cotter:
• “If the vaccine is given for Bordetella -- kennel cough -- it is best used intra-nasally, not by injection.
• “Leptospirosis and Borrelia (Lyme) vaccines should be given only to dogs at significant risk. Geographic variation exists for risk.” Among other states, canine leptospirosis has been reported in Florida, Alabama, Georgia, Massachusetts, New York and New Jersey. It’s spread through the urine of affected wild animals. (Diplomates of the American College of Veterinary Medicine believe the use of Lyme vaccines still is controversial and most do not administer them.) Lyme disease has surfaced in all states but predominantly in the Northeast, North Central and Northern California. The vaccines give only partial, relatively short-term immunity.
• “Vaccines against canine adenovirus-1 [an older form of hepatitis], giardia and coronavirus are not recommended.”
• “Killed rabies vaccine should be given to all puppies at 3 months of age and 1 year later,” Dr. Cotter said. “After that, it is effective for three years, even though some states continue to require it yearly.
– A vaccine for measles, a virus similar to distemper, is no longer recommended as part of routine puppy vaccinations.
“Tufts follows the recommendations of AAHA,” said Mary Labato, DVM, an internist at the Cummings School. “There have been studies looking at viral exposure to animals vaccinated long ago to see how protective immunity is. That demonstrated that we could extend out the vaccine protocols. But it is still up to the individual veterinarian.”
The updated guidelines -- available at www.aahanet.org -- are changing how veterinarians practice medicine and will impact the way manufacturers market their products. The yearly veterinary visit that once emphasized vaccinations will now focus on wellness care. The new guidelines encourage rational vaccination rather than simply use-it-because-it’s-available, said internist Richard B. Ford, DVM, faculty member at North Carolina State University and a member of the Canine Vaccine Task Force.
Thirty to 40 years ago dogs received only four kinds of vaccines. Giving distemper, hepatitis, leptospirosis and rabies vaccines to all dogs was considered state-of-the-art medicine, said Dennis Macy, DVM, a professor and internist at Colorado State University School of Veterinary Medicine.
At the time, studies determined that immunity against distemper lasted less than one year in 33 percent of vaccinated dogs, said Dr. Macy. Based on that decades-old study, annual revaccination became the default recommendation, and soon veterinarians were revaccinating dogs annually with all available vaccines.
When dogs received more and more shots each year as new ones became available, veterinarians and owners noticed adverse reactions. Sensitive dogs like Pepper and Nikki suffered possibly lethal anaphylactic reactions -- toy breeds seem most susceptible. Over-vaccination also has been linked to chronic immune-mediated conditions, such as polyarthritis -- multiple joint arthritis -- and inhaled allergies, said Dr. Macy. In rare cases, live vaccines induce the disease they were designed to prevent. “The only cases of distemper we saw at CSU last year were vaccine-induced,” he said.

An Array of Choices
The number of vaccinations and ways they’re manufactured and administered have increased to a smorgasbord of choices. They include “mega-combos,” often referred to as the five-way, six-way or even eight-way injections.
Today, more than two dozen types of canine vaccines in more than 100 different products are on the market. “That alone drives the need for us to look at how often we vaccinate with which vaccines,” Dr. Ford said.
One complicating factor: “There has been no change in most vaccines as to how they are licensed and what the packet insert recommends as to vaccine frequency and boostering,” Dr. Labato said. That has raised concerns among some veterinarians regarding liability if they vaccinate contrary to label specifications. So far, only a few manufacturers provide three-year labels.
Because duration of immunity may vary widely, the “combo” shots may result in dogs being under-vaccinated for some agents and over-vaccinated for others. Dr. Macy said as a result he’s now seeing manufacturers “de-packaging” combo shots, which allows veterinarians to more easily customize vaccinations.
In other changes to the guidelines, categories of vaccines are now designated core, or recommended; non-core, or optional; and not recommended. The categories are based on health risks associated with infection, incidence and severity of a disease, and the vaccine’s effectiveness.
Core vaccines should be administered to every dog 6 months old or older or who hasn’t previously received vaccinations. They prevent diseases that are particularly dangerous, have wide distribution or are contagious to people. Rabies vaccinations are considered core, with both the one-year injection lasting three-plus years, but again, state laws may mandate a different frequency.

Treatable Infections
Non-core includes vaccines that protect dogs against less common or less severe infections that are either self-limiting or treatable, such as coronavirus. Non-core vaccines should be given only to dogs at risk for exposure. Deciding factors include age, the disease’s geographic distribution and lifestyle. For example, dogs kept strictly indoors may be less likely to be exposed to diseases than free-roaming animals.
Shelter medicine recommendations, which are new to the 2006 publication, differ from those for the private practitioner. They don’t use the terms core and non-core. “We’re trying to manage, not prevent, disease in the shelter setting,” Dr. Ford said.
Vaccines designated as not recommended are associated with potentially serious adverse events and/or don’t prevent infection. “The easiest example is the old hepatitis vaccine -- the adenovirus-1,” said Dr. Ford. “Dogs can lose their vision, dogs can lose their kidneys, and they can die [if vaccinated with it].”
Veterinarians no longer use the adenovirus-1 vaccine because it’s considered risky, but some products remain available through catalog and Internet sales, usually in the multi-dose vaccines. Seventeen to 19 percent of vaccinated dogs in the U.S. receive vaccines through the Internet or catalogs, risking illness if a dangerous vaccine is used or vaccination is given inappropriately, Dr. Ford said.
The American Veterinary Medical Association has expressed concern that veterinarians have no mechanism for reporting and receiving adverse drug and vaccine information. “There is no rule or law that adverse reactions actually be reported,” said Dr. Labato. Therefore, accurate numbers are not available. It’s too soon to tell if adverse events have declined as a result of new vaccination recommendations, she said.

Develop a Database
“There is a proposal out now to develop a centralized database to report, comparable to the Vaccine Adverse Event Reporting System used by the FDA in humans,” said Dr. Ford. “It’s probably a couple of years away.”
The Canine Vaccine Task Force recognized that not all veterinarians agree which vaccines belong in each category. Therefore, the guidelines encourage individual practices to designate the vaccines that constitute core and non-core for their practice, based on a health risk assessment.
The vaccines that are given and their frequency require medical judgment. “We want consumers to know that vaccination is absolutely the best buck for the dog’s health dollar,” Dr. Ford said. “If dogs need vaccinations at that annual exam, it’s a good time to give them.”
In the final analysis, Dr. Cotter said, “The important point is that the benefits of recommended vaccines far outweigh any risks.”

Amy D. Shojai is free-lance writer in Sherman, Texas.

SIDEBAR:
Tests to Monitor Immunity
Vary in Accuracy and Usefulness

When vaccine guidelines first recommended revaccination at three-year intervals rather than one were published three years ago, some veterinarians and owners were reluctant to trust the report. They turned to antibody titer tests to measure immunity, and controversy ensured. “Titers probably stand out as one of the preeminent issues for veterinarians,” said Dr. Ford.
Antibodies are specialized protective proteins created by the immune system when exposed “naturally” to a virus or bacterium or when given a vaccine. Measuring immune components in the blood -- serum antibody titers -- helps determine if a dog has an adequate protection to a given disease agent. Theoretically, this determines if the dog requires revaccination or has sufficient duration of immunity.
While many laboratories today offer vaccine titer tests, they often cost more than revaccination and may not be cost effective for many owners. More to the point, no standard method exists for measuring vaccine titers. What one laboratory defines as a protective antibody level may be defined differently by another. Different test methods, varying in accuracy and usefulness, also exist.
For instance, the existing titer tests for leptospirosis are used only to assess infection, not protection. “Titer or no titer, the leptospirosis vaccine does not guarantee any prevention against infection,” said Dr. Ford.
Individual dogs may have very high titers for extended periods of time for some but not all vaccines. Also, different infectious agents and vaccines create different levels of immunity. Some last longer than others, making duration of immunity studies even more critical.
“There are only two titers that carry any weight, and that’s distemper and parvo,” Dr. Ford said. “Those are the only ones I’d recommend that anybody do.”

c 2006 Cummings School of Veterinary Medicine at Tufts University "Your Dog: the newsletter for caring dog owners"