Last week I gave a basic overview of vaccinations, including a discussion of why dogs need them. I made the distinction between core vaccines (those that every dog needs for public health reasons, including rabies, which is required by law) and noncore, which should be administered depending on a dog’s particular circumstances — exposure to other dogs, for example, or geographical location. The American Animal Hospital Association (AAHA) recommends that noncore vaccines be given whenever the risk of the disease is high enough to override the risk of vaccination.
Here I pick up with a discussion of “the risk of vaccination” part of that equation.
Very few dogs — less than ½ of 1% — have adverse reactions to vaccination. And most of those reactions are mild. But if your dog falls into a high-risk category (see the “Is Your Dog at Risk?” box) or you prefer to err on the side of caution, there are strategies that can help mitigate any potential problems.
A very large, comprehensive study — 1,226,159 dogs vaccinated with 3,439,576 doses of vaccine at 360 veterinary hospitals — conducted in 2005 determined that the dogs at greatest risk of having an adverse reaction to immunizations were young adult, small-breed, neutered dogs who received multiple vaccinations during a single office visit. (The results of this study can be found in JAVMA — Journal of the American Veterinary Medical Association — Vol. 227, No. 7, October 1, 2005; I would attach a pdf if I knew how.)
Most reactions fell into the following categories: swelling of the face and eye area (31%); raised, itchy areas (21%); generalized itching (15%); vomiting (10 %); swelling, inflammation, or soreness of the vaccination site (8 %); fever, lethargy, and lack of appetite (5.5%). Most dogs were successfully treated with an antihistamine and/or glucocorticoid (steroid that reduces inflammation).
— Small breeds. The larger the dog, the lower the risk of a reaction. Here’s why, and it’s a shocker: The manufacturers’ recommended dose for vaccines are not adjusted for body weight, in contrast to doses of almost all other veterinary pharmaceuticals.
Within the small breed category, the dogs most likely to experience symptoms after vaccination were dachshunds, pugs, Boston terriers, miniature pinschers and Chihuahuas. A genetic predisposition to allergies likely plays a role in this response because, in general, small mixed breeds had far fewer bad reactions to vaccination.
— Multiple vaccinations: The risk of a reaction increased as the number of vaccine doses administered per office visit increased, especially with small dogs. Each additional vaccine increased the likelihood of reaction by 27% in dogs that weighed less than 22 pounds and 12% in dogs larger than 22 pounds.
— Neutered dogs: Both male (27%) and female (38%) neutered dogs were more likely to have a reaction than sexually intact dogs.
— Young adults: Dogs of approximately 1 to 3 years old had the greatest number of adverse reactions, which is probably related to the fact that most boosters for puppy vaccinations are administered during this age span. Dogs older than 8 years experienced the fewest side effects.
There’s little you can do about most of the risk factors noted here — you can’t change your dog’s size or age or un-neuter him — but you can control how many vaccines you have your vet administer at a time. This requires spending additional money on individual office visits, but with an at risk dog it’s likely worth the investment in your peace of mind.
Another peace-of-mind inspiring tactic is to wait in the vet’s office for half an hour after the vaccination. Some 73% of reactions take place within the first 24 hours, and the most severe ones occur almost immediately.
Titers are blood tests that measure the level of immunity your dog has against various diseases by measuring the level of antibodies in the blood. Titering, also called vaccine serology, is becoming increasingly common.
Although effective in many cases, titering has several limitations, including expense. In addition to the cost of an office visit, you have to have your dog’s blood drawn and sent to be analyzed by a laboratory. Then, if your dog doesn’t show immunity, you have to return to the vet for a vaccination.
And titers are not available for all diseases. The most commonly administered and the most reliable are for the core diseases, parvovirus and distemper (there is also a titer for rabies, but no state allows its substitution for vaccination). Nor are all titer tests as useful as others. Linda Ross, DVM, ACVIM at Cummings School of Veterinary Medicine at Tufts University, gives the example of leptosporosis, which has many strains. A titer test might find antibodies for one subtype of the disease, but your dog might still be susceptible to others. In addition, titers aren’t always a good gauge of the level of protection. Some dogs that don’t have a measurable number of antibodies nevertheless have immunity to the disease.
There is also the question of how often to titer. Dr. Ross asks the hypothetical questions: “If your dog has antibodies to a certain disease, when do you check again? The following year? Two years?” Still, Dr. Ross says, “If a client is concerned, especially the owner of a breed that’s susceptible to a reaction, having titers done is a good alternative to vaccination for those who can afford it.”
Talk to your Vet
Overall, the most important way to feel confident about your dog’s immunizations is to discuss them in detail with your veterinarian. It’s a two-way street. On the one hand, you should be comfortable asking about the potential side effects of any proposed vaccinations and how to recognize them. Inquire too about whether there are any restrictions for your dog in the days immediately following vaccination.
In turn, you should make your vet aware of any symptoms or medical issues your dog is experiencing; if your dog’s immune system is preoccupied with fighting off another disease, vaccination should usually be postponed. It’s also crucial to let your veterinarian know about any side effects your dog might have experienced in the past, even if you considered them too minimal or unrelated to report them at the time.
As Dr. Ross notes, you can expect your veterinarian to be very familiar with the ins and outs of vaccination because it’s a routine part of every practice. This is one instance where the generalist is a specialist.