What are titers, related to vaccines?

What are titers and what do they mean for my dog?

by Anne Jones RN, BSNE

Probably the hottest topic in the life of dogs today is vaccination protocol. How often should my dog receive vaccines and which ones should he receive? That topic is covered elsewhere but the basic thinking today is that dogs carry immunity for much longer than one year and that they only need a few basic (Core) vaccines unless there are exceptional reasons for others, such as for Lyme disease. You can read in more detail about Bichons and vaccines and about the immune system in another place.

One recommendation that you will read is to use titers once the basic immunity has been established. Current thinking and recommended protocol is that boosters past the first one should be no more often than every three years. This is the current "safe" veterinary recommendation but research is ongoing and vaccines have proven to be effective for much longer than three years and titers can substantiate that your dog does remain immunized. So what is a titer?

A serum antibody titer is a blood test that measures the immune response to a disease-causing organism. The test actually measures the antibody response when challenged and the response (or antibody level) reflects past exposure or vaccination to a particular disease - or a need for additional protection in order to prevent infection. A positive result shows presence of adequate antibodies and a negative indicates need for protection. The most common titers in dogs are those that test for CPV (canine parvovirus) and CDV (canine distemper virus) but there are others. Only when the serum antibody tests show protection to be less than adequate is it necessary to give boosters. Though a rabies titer is available, state laws may vary as to whether a titer can replace vaccination boosters.

Different laboratories may have different standards of protective response so it is important that your veterinarian is knowledgeable about the recognized standard for the lab he/she is using. However a general rule will be that the higher the titer reading, the greater the protection. A dog that has an acceptable reading does not need further protection and giving booster vaccines will challenge the immune system needlessly to produce more antibodies. Studies indicate that immunity is maintained once it becomes established at a given level, regardless if from vaccines or from having the disease. Testing every 2-3 years will show when that level is reached.

Actual expected readings will vary from lab to lab so it serves no purpose in quoting the expected values. The important message in this article is to state that having titers run on your dog, while possibly more expensive than boosters in some clinics, are cheaper in the long run than treating immune mediated illnesses that can be fatal. Comparison studies continue as to the how long dogs retain immune status after initial vaccines and first boosters. Your best ally in protecting your dog will be your own veterinarian but you may need to have frank discussion with your vet to come to an agreed upon policy for giving boosters or using titers. The current stated protocol for core vaccines (distemper, parvo, adenovirus and rabies) is every three years but expect that time frame to be extended as research supporting lasting immunity reaches the veterinary journals. Titers are the safe course to follow.

Source: http://www.bichonhealth.org/HealthInfo/Titers.htm