by Jan Rasmusen
Enlightened veterinarians and pet parents have become increasingly wary of the health risks, and lack of benefits, associated with repeatedly vaccinating dogs after their initial “puppy shots.”
Is titer testing the solution to the over-vaccination problem?
Here’s a crash course to help you muddle through the mire of misinformation surrounding this simple blood test, and to help you decide whether or not to test your dog’s antibody titers.
What is Titer Testing?
A titer test (pronounced TIGHT-er) is a laboratory test measuring the existence and level of antibodies to disease in blood. Antibodies are produced when an antigen (like a virus or bacteria) provokes a response from the immune system. This response can come from natural exposure or from vaccination. (Note: titering is also called serum vaccine antibody titering and serologic vaccine titering.)
How is the Test Performed?
Your test result will have an explanation of what your pet’s test result means. But if you want to know more, here’s the test in a nutshell:
1. One mL of blood is drawn.
2. The sample is then diluted.
3. Titer levels, expressed as ratios, indicate how many times blood can be diluted before no antibodies are detected.
If blood can be diluted a 1000 times and still show antibodies, the ratio would be 1:1000. This is a “strong” titer. A titer of 1:2 would be weak.
Should I Test for All Diseases?
The most recommended test examines antibodies for both parvovirus and distemper, the two most important viruses. Rabies titers are also often tested. Usually, for most dogs, tests for other diseases are generally not considered useful or necessary.
Why Titer Test?
The parvovirus/distemper test can help you or others (vets, groomers, kennel owners, etc.) determine if your dog requires additional vaccination, and may save your dog unnecessary shots. It is especially useful when making a decision about vaccinating an animal with unknown vaccination history, or for determining if puppies have received immunity from vaccination.
Most experts believe strong titers are a more reliable indication of immunity than vaccination: tests show the actual immune response, not just the attempt to cause an immune response by vaccination. Do not expect, however, that everyone will accept test results in place of proof of vaccination.
The subject of immunity is complicated, and we are programmed to think of vaccination as “the gold standard” — the more, the better. Experts who challenge the status quo are often maligned. Humans don’t like change.
How often should I Test Titers for Parvo and Distemper?
You’re going to have to decide for yourself. Some vets recommend testing yearly, but this can be expensive. Others test every three years. Still others test five to seven years after vaccination.
Challenge tests show that successful vaccination against parvovirus gives most animals at least seven years of immunity. Distemper provides immunity for at least five to seven years.
Dr. Ron Schultz, one of the most renowned pet vaccination experts in USA, believes that once a test yields strong titers, you need not test again.
In Dr. Jean Dodd’s article on vaccine reactions, she quotes Dr. Schultz on the value of testing titers: “an animal with a positive test has sterilizing immunity and should be protected from infection. If that animal were vaccinated it would not respond with a significant increase in antibody titer, but may develop a hypersensitivity to vaccine components (e.g. fetal bovine serum).”
Does a Weak Titer Mean My Dog Needs a “Booster” Shot?
Maybe not for dogs that have previously shown strong titers. Many experts, including Dr. Schultz, say the dog’s immune system will have produced “memory cells” that will produce antibodies when they’re needed. Think of memory cells as reserve forces.
When known foreigners invade, they remember how to attack them. Dr. Shultz has said, “show that an animal with a positive test has sterilizing immunity and should be protected from infection. If that animal were vaccinated it would not respond with a significant increase in antibody titer, but may develop a hypersensitivity to vaccine components (e.g. fetal bovine serum).
Should I Test My Puppy?
Yes! If so, when? Ideally, puppies should have had their last vaccination after 16 weeks of age then should be tested to see if further vaccination is necessary. Such titer testing is the only way to ensure that a puppy has developed an immune response after vaccinating.
What do Titer Tests Cost?
Testing costs vary widely from practice to practice, so shop around. Some vets do in-house testing. Others use outside labs. Some mark up tests and services a little; others, a lot. You should be able to have parvo/distemper tests done most places for less than $100. Rabies tests, on the other hand, can cost considerably more, in large part because they are sent overnight to a lab.
Before jumping to the conclusion that vaccinating is much cheaper than testing, remember that testing can be a one-time (or at least rare) expense and is no riskier than any simple blood draw. Vaccinating, on the other hand, can potentially cause a lifetime of illness.
Should I Titer Test for Rabies?
The rabies titer test will give you an indication of your dog’s immunity if he or she is at particular risk for contracting rabies. It may be required prior to international travel.
(Note: a French challenge study has shown rabies vaccination gives immunity for at least five years. In the U.S, the Rabies Challenge Fund is doing concurrent tests for five years and seven years to extend the period between shots. This important nonprofit study is funded solely by donations from dog lovers like you.)
Can I Titer Test Immediately After Vaccination?
To get an accurate test, you must wait at least 14 days after vaccination before testing.
What if your vet, groomer, spouse, best friend, kennel owner or day care proprietor says titer testing is “voodoo science,” that your dog needs continued vaccination even if testing indicates otherwise?
Know that vets out of school longer than 10 years received little or no immunology or vaccinology training in school; they shouldn’t be considered experts unless they’ve devoted hundreds of hours to research and training. Others who want to influence you may have no training at all and may be acting out of fear.
Do your own research and advocate for your dog.