“VETERINARIANS AND DOG OWNERS NEED TO KNOW ABOUT BOTH THE BENEFITS AND RISKS OF VACCINES AND OTHER THERAPEUTICS.”
Donald Klingborg
Two new reports on vaccines issued in the past year indicate that adult dogs may not need to be revaccinated annually. These reports issued by the American Veterinary Medical Association (AVMA) and the American Animal Hospital Association (AAHA) tell us that immunity protection for core vaccines – distemper, parvovirus, adenovirus and rabies – are likely to last much longer than one year.
Duration of immunity (DOI) – how long immune protection lasts – is the critical determining factor, but it is not simple to define because it is based on the complex interplay between a dog’s immune response and the vaccine and may be difficult to assess in an individual dog, according to the AAHA report. Vaccine use should be determined based on disease incidence and severity, vaccine protection and safety, and the health, welfare and lifestyle of an individual dog.
Ultimately, both associations say it is impossible to make a general statement on the use of vaccines. Instead, they encourage veterinarians to adopt customized vaccination programs that focus on what is best for a particular dog. Revaccination recommendations should be designed to create and maintain clinically relevant immunity while minimizing adverse event potential, the AVMA report says.
Predisposed Breeds
For breeds such as the American Cocker Spaniel that are more prone to adverse vaccine reactions including immune-mediated hematological conditions, alternative approaches are best for preventing infectious health conditions, says W. Jean Dodds, D.V.M., an immunologist/hematologist and president of Hemopet in Garden Grove, Calif. In an article in the May/June 2001 issue of the Journal of the American Animal Hospital Association, Dodds advocates measuring serum antibody titers, avoiding unnecessary vaccines, and using caution in vaccinating breeds known to be at risk for immunological reactions.
Dodds began studying families of dogs with increased frequency of immune-mediated hematological conditions 30 years ago. Among the more commonly recognized predisposed breeds are the Akita, American Cocker Spaniel, German Shepherd Dog, Golden Retriever, Irish Setter, Great Dane, Kerry Blue Terrier, and all Dachshund and Poodle varieties. For these breeds, Dodds’ recommendation is to give the puppy vaccine series and then to refrain from giving booster vaccinations until at least after puberty, if at all.1
Ultimately, veterinarians should be encouraged during the initial visit with a puppy owner or breeder to review current information about the breed’s known congenital and heritable traits, Dodds says. For those breeds at increased risk, the potential for adverse reactions to routine vaccinations should be discussed as part of this wellness program.1
No Perfect Vaccine
Vaccines are medically powerful agents for which important medical decisions considering relative risks and benefits must be individualized to the needs of the dogs, says the AVMA report. Vaccines are designed to minimize the adverse clinical signs associated with the disease, but may not prevent infection.
Early vaccines from the late 1950s lacked the safety and efficacy of current products and often resulted in adverse reactions or short durations of immunity.2 Thus, the recommendations for revaccination of core vaccines – annually for parvovirus, distemper and adenovirus and one to three years for rabies, based on state law – reflect these limitations and are based on a better safe than sorry approach. After all, the diseases these vaccines were designed to prevent were widespread and devastating.
Core vaccines are given for conditions that cause significant morbidity and mortality and are widely distributed. Vaccinations are of paramount importance in breeding kennels, where population density and the opportunity for exposure to other dogs are among the most critical issues.
Scientific knowledge about vaccines has resulted in tremendous improvements; however, the ultimate goal of combining 100 percent efficacy and 100 percent safety into the same vaccine product is not a reality at this time.2 A vaccine that is virtually free of all adverse side effects would likely be a poor stimulant of immunity or produce a short DOI.
Although most dogs respond well to vaccines, vaccination carries some risk. Some of the most common adverse reactions are mild and short term and include fever, sluggishness and reduced appetite. Dogs also may experience temporary pain or subtle swelling at the site of vaccination. Although most adverse responses resolve within a day or two, excessive pain, swelling or listlessness should be discussed with a veterinarian. If a dog has repeated vomiting or diarrhea, whole body itching, difficulty breathing, collapse or swelling of the face or legs, a veterinarian should be contacted. These signs may indicate an allergic reaction, and in rare instances, death may occur.3
Immune-Mediated Reactions
Clinical signs associated with immune-mediated reactions to vaccinations include susceptibility to autoimmune hemolytic anemia (AIHA) and immune-mediated thrombocytopenia (ITP), a condition that results in decreased blood platelets.1 In addition, liver enzymes may be markedly elevated, liver or kidney failure may occur independently or accompany bone-marrow suppression, and seizures may occur in puppies and adult dogs. Reactions may occur from 24 to 72 hours after vaccination, or seven to 45 days later in a delayed-type immunological response.3 For breeds or families of dogs with increased frequency of immune-mediated hematological conditions, Dodds recommends measuring serum antibody titers to reduce the risk of adverse reactions and to avoid unnecessary vaccinations. “This blood test helps to determine whether or not your dog will be protected from the infectious health condition if it were to be exposed,” she says.
Reporting Adverse Reactions
Currently, there is no federal or state mandate for veterinarians to report adverse events associated with vaccination. “The need is obvious,” says Donald Klingborg, chairman of the AVMA council that prepared the vaccine report. “Veterinarians and dog owners need to know about both the benefits and risks of vaccines and other therapeutics. We know more about the benefits because there is an insufficient system to capture, analyze and report adverse events associated with vaccine products.”
Reporting could lead to the detection of unrecognized reactions and increase awareness of known reactions, to the recognition of risk factors associated with reaction, to the identification of vaccine lots with unusual events or unexpected numbers of adverse events, and to further studies.1
Options for Maintaining Vaccinal Immunity
Vaccination schedules should be modified on the basis of changes in a dog’s age, health status, home and travel environment and lifestyle. Most important, vaccinations should be considered just one part of an individualized comprehensive, preventative health-care plan.
Alternatives to annual booster vaccinations such as serum vaccine titer testing should be considered. By checking titers annually, one can assess whether a dog’s potential immune response has decreased to unacceptable levels. In that event, appropriate vaccine booster can be administered.
Used with permission from the Purina Pro Club Cocker Spaniel Update, Nestlé Purina PetCare Company.
1 Dodds WJ. Vaccination Protocols for Dogs Predisposed to Vaccine Reactions. Journal of the American Animal Hospital Association. 2001;37:1-4.
2 Report of the American Animal Hospital Association (AAHA) Canine Vaccine Task Force: 2003 Canine Vaccine Guidelines, Recommendations, and Supporting Literature.
3 What you should know about Vaccination brochure. American Veterinary Medical Association. Revised 10/02.
The 2009 ASC Annual Flushing Spaniel Show