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For most of us who share our lives with dogs, making sure they are vaccinated tops the list of preventive-care tasks. We mindfully take our puppies or newly adopted dogs for their recommended vaccines. We routinely return to our veterinarian or vaccine clinic when that postcard or email arrives, reminding us that our dogs are due for booster shots. We know vaccination offers critical protection from diseases such as canine parvovirus, canine distemper virus, rabies and more.
However, many of us question the concept of “routine” when it comes to vaccinations. While grateful for the protection that vaccines offer, we are increasingly aware of their possible unintended consequences. That’s where titer testing comes in.
Titer tests are among the tools that dog owners and veterinarians can use to help minimize the risks of both infectious diseases and unnecessary vaccinations. Simply put, these tests can tell you if a previous vaccine is still protecting your dog. If it’s still working, you don’t have to revaccinate.
Dr. Evelyn Sharp of My Personal Vet  in Santa Cruz, Calif., has used titer tests with her own dogs since she began practicing veterinary medicine in the mid-1990s. The first dog she regularly tested was her Border Collie mix, Ace. Titers showed that the protection provided by Ace’s initial puppy series and one-year booster lasted the rest of his life. With the recent availability of in-practice titer-test kits—VacciCheck from Biogal Laboratories and TiterCHEK from Synbiotics Corporation—titer testing has become even easier to do.
Because the newer titer-test kits are affordable, accurate and can be run inhouse (rather than by a lab), Dr. Sharp now suggests titer testing as part of preventive care. With the information she gets from the titers, she can provide a customized vaccination protocol for each dog, keeping the dog well protected while minimizing the risks of over-vaccination.
The most recent American Animal Hospital Association  (AAHA) Canine Vaccination Guidelines say that reported side effects from vaccines vary from injection-site reactions, lethargy, lack of appetite and fever to more serious adverse events, including allergic reactions, autoimmune problems and, rarely, sarcoma or other tumors. The decision about when to vaccinate requires a riskbenefit analysis. Most experts agree that vaccines are critical to the overall health and wellness of our dogs (and cats), but many also agree that giving a vaccine when it is not needed exposes animals to unnecessary hazards.
So what exactly is involved in titer testing? A “titer” is a method of measuring antibodies in a blood sample for specific diseases. Your vet will draw a small amount of blood and then run that blood through the test. Titers are usually expressed as a ratio; if the titer number is high, it means that your dog has enough antibodies to fight off that specific disease and is considered to have immunity from infection. For many of our dogs, that immunity is the result of a previous vaccine. However, immunity can also develop because a dog had the disease in the past. Either way, a high titer means your dog is protected.
If the test shows a low titer, your dog may not have immunity. The interesting and perhaps odd detail (odd, at least, from a layperson’s viewpoint) is that a low titer is not completely definitive. A dog may still have some protection. Still, the accepted standard with the in-house test kit is that a low titer means that you and your veterinarian should discuss revaccinating.
Just as vaccine prices vary, the price of a titer test can also vary from veterinary practice to veterinary practice. According to Dr. Sharp, the VacciCheck tests three diseases—parvovirus, distemper and adenovirus (canine hepatitis)— and generally runs between $45 and $80, which is a little more than most vaccines, but not unreasonably high.
AAHA vaccine guidelines say that titer testing is an appropriate way to check for immunity to parvovirus, distemper and adenovirus. However, it is not recommended for canine leptospirosis, bordetella or Lyme disease, because these vaccines only provide short-term protection.
Rabies vaccines do provide long-term protection, and the titer tests for rabies are also considered to be a very accurate measure of immunity. However, vaccination against rabies is mandated by law and at this time, no state in the U.S. accepts titer-test results in lieu of vaccination history. If your dog bites someone, she will still need to be quarantined, even if a titer test shows she has immunity. Specific types of rabies titer tests are used, however, when moving to rabies-free countries or regions—for example, Hawaii, Guam, Japan, New Zealand or Great Britain. In this case, the rabies titer test will help qualify a dog for a shorter quarantine.
Along with using titer tests to check for immunity to parvovirus, distemper and adenovirus in a previously vaccinated adult dog, titers are also a good option for a newly adopted dog whose vaccination or health history you may not know. In addition, a titer test may be used to make sure young puppies have responded to the initial vaccine series and are fully protected. If a pup did not respond, the vaccine may have been compromised, the mother’s immunity may still be active or the pup may be a non-responder (meaning she will not have an immune reaction to vaccines). Your veterinarian can help you decide on the best course of action if your pup does not have an acceptable titer.
Another place titer tests are gaining momentum is in the shelter environment, although with a much different goal than when used with individual dogs. There, titers are being used to help separate low-risk and high-risk dogs and cats during a disease outbreak. Shelter dogs who have a high titer to the outbreak disease—meaning they are at low risk for infection—can be separated from the higher-risk animals, and they may be considered adoptable. (You can learn more about titer testing in shelter environments by visiting maddiesfund. org and searching for “titer tests.”)
While vaccinating animals against infectious diseases is critical to protecting individual dogs and communities at large, over-vaccinating is also a real concern for those of us who share our lives with dogs. Titer tests give us another tool and can help when it comes time to discuss vaccines with our veterinarian and make the best health-care decisions for our dogs.