The story of an adverse canine vaccination reaction detailed in recent weeks in my friend Roxanne Hawn’s Champion of My Heart blog inspired me to go back to a piece I wrote for Your Dog newsletter in late 2010. It’s long, so I broke it into two parts. Part 1 puts the larger issues of vaccination in context, while Part 2 discusses what can go wrong — and how to try to prevent it .
Why Vaccinate?
Vaccinations are not only essential to the health of your dog. By preventing the spread of dangerous, highly contagious diseases, they’re also key to the health of the canine community. But one size doesn’t fit all. The type and frequency of vaccines that dogs receive need to be tailored to their individual, ever shifting, circumstances.
Linda Ross, DVM, ACVIM at Cummings School of Veterinary Medicine at Tufts University, stresses the need to discuss vaccination with your veterinarian. “Beyond the vaccines that are generally recommended for all dogs, there are others that depend on where you live, whether you put your dog in a kennel, go to the dog park, etc.,” she says. “A vet who is familiar with your dog’s routine and medical history can help you decide what’s best for your pet at different life stages.”
Vaccination is the introduction — usually by injection but sometimes nasally or transdermally (by direct application to the skin) — of killed or deactivated organisms in order to provide immunity against the diseases they cause.
The vaccines in widespread use fall into two general categories: the core group, recommended for dogs across the board, and the noncore, which are prescribed based on a dog’s individual circumstances.
Core Vaccines
Core vaccines protect against diseases that are common in North America, that are particularly dangerous and difficult to treat, and that are very easily transmitted. The American Animal Hospital Association (AAHA) Canine Vaccination Guidelines includes in this group distemper, which often causes seizures and spinal cord damage; parvovirus, resulting in severe vomiting and diarrhea; adenovirus, an upper respiratory illness (the vaccine also helps prevent canine hepatitis); and rabies, as dire as depicted in horror films but usually more quickly fatal than plot requirements dictate
Dr. Ross explains that, in order to make sure individuals don’t get these diseases, the entire population has to be vaccinated against them. “This may be where some people’s confusion comes in,” she says. “Owners say, ‘My dog gotten hasn’t gotten vaccinated and he hasn’t gotten sick.’” This is true, she points out, only because these diseases have been widely eliminated as a result of major vaccination programs. “If the percentage of immunization in the canine population were to drop and one of these diseases were to turn up, it would spread very rapidly,” Dr. Ross says.
Of the four core vaccines, rabies is a special case. Because this agonizing illness can be spread to humans as well as to other dogs and it has an extremely high mortality rate, vaccinations are required by law in the United States. “Rabies is always fatal to the animals,” Dr. Ross says, “and it’s fatal to humans about 99.99 percent of the time.”
Noncore Vaccines
Geography and travel habits are among the factors veterinarians take into account when recommending noncore vaccines, which protect against diseases that are less widespread and, usually, less dangerous, although severe enough to want to minimize their threat. They include parainfluenza and Bordetella, both associated with kennel cough; canine influenza; Leptospirosis, which causes liver and kidney dysfunction; and Lyme disease, transmitted by the same tick that infects humans but causing somewhat less severe symptoms in dogs.
According to the AAHA, health threats associated with these diseases vary not only by region but also from city to city and even from one section of town to another. Southwest desert-dwellers don’t have to worry about inoculating their dogs against Lyme disease, for example — unless they take them on regular summer vacations to the northeast shore, the type of warm, humid environment where the disease-bearing ticks thrive.
Lifestyle is another thing vets consider when suggesting vaccinations. Dogs that don’t go to daycare and who are not boarded overnight generally don’t need to be concerned about kennel cough, for example.
How soon and how often?
Except in the case of rabies, where immunization is government mandated, there are no strict protocols for veterinarians to follow when determining which vaccines to give their canine patients. Also not standardized — and far more complex in its variables — is the frequency with which vaccines are administered. The duration and degree of immunity provided by each vaccine varies from manufacturer to manufacturer as well as from dog to dog, depending on age, breed and general health.
It’s generally agreed that dogs need to complete a series of core vaccinations when they are puppies and then get booster shots a year later. Dr. Ross says, “We’re never entirely sure when the immunity from the mother wears off but, assuming the puppies were nursing, we recommend starting a series of vaccinations at eight to ten weeks.” Anything before six weeks is too early, she notes. After the initial vaccinations, follow-ups should be given over a period of three or four weeks, with the final immunizations given at 12 to 16 weeks. “Wait one year after the final shot to give the booster,” Dr. Ross suggests, “rather than scheduling them a year from the first shot.”
After the initial one-year booster, the AAHA Canine Vaccine Guidelines recommend that the distemper, adenovirus and parvovirus core vaccines be administered once every three years. This cut back from what was once an annual booster is in keeping with the growing recognition that protection lasts longer than previously thought. It’s hypothesized that, in adult dogs that have been boostered since they were puppies, immunity may last for 5 to 7 years or even a lifetime. This has led veterinarians to vaccinate less frequently for the core diseases.
However, for an adult dog that doesn’t have a documented vaccination history, Dr. Ross advises adopters to repeat an initial vaccination for the core diseases after three to four weeks. She suggests a quarantine period for dogs from shelter or rescue groups that are adopted into homes where there are other pets.
Special Cases: The Shelter
Animal shelters create an environment that is particularly conducive to the spread of disease — a fact that has been recognized by the AAHA, which has a separate section for shelter medicine in its vaccination guidelines. “Core diseases are more likely to turn up in shelters, which often house litters of young animals that have not been vaccinated,” Dr. Ross says. And because shelters tend to keep a lot of animals in a confined space, diseases can spread rapidly, no matter how much care the shelter staff takes. The AAHA guidelines advise that dogs at least six weeks old be vaccinated as soon as they enter the facility, with the age lowered to four weeks if there’s already an outbreak.
When coming into a home with other pets, the new family member should be isolated initially. “If the dog hasn’t been vaccinated, you need to have it done immediately,” Dr. Ross says. And it’s important to allow time for the vaccination to take effect or for a disease that the dog might have been exposed to pre-vaccination to show up. Dr. Ross recommends two weeks of separation from the other pets. “That may be a little long,” she says, “but it’s better to err on the side of caution.”
Dogs bought from a pet store need to be treated in the same was as shelter dogs, according to Dr. Ross. Even if they didn’t come from puppy mills, as almost all pet store dogs do, they’re usually kept in close quarters with other dogs of unknown origin.
For more about the special circumstances of shelter medicine, see Shelter Medicine: Veterninary Challenges and Solutions.