Titers and Vaccinations


What Is A Titre and Why Should I Measure One?

Titre is correctly spelled titre or titer.  It is pronounced tight-er.  It is a blood test which measures the immune response to an antigen exposure.  The number measured is an antibody level present at different titration or dilution levels of the blood.  The antigen that the body has been exposed to in order to stimulate the immune response could have been present in a vaccination or the disease itself.  If antibody levels are present in highly diluted blood, then that’s a high titre.  A high titre level may indicate lots of exposure, lots of protection or perhaps long-lasting immunity.  The titre level is one indicator of the body’s immune response to an antigenic stimulation.


A lot of research has been performed on dog and cat serum to establish what antibody titre levels are protective against distemper/parvo and distemper/rhino/calici respectively.  Comparable research does NOT exist to assert what titre levels are protective against the rabies virus.  Challenge studies based on time interval since last vaccination have been performed for rabies.  This is what dictates the 1 year initial, 3 year booster rule.  There is an ongoing study to try to prove the 3 year vaccine for rabies actually protects for 5 years.


It is useful to understand that the titre measures antibody levels in the blood which is part of the body’s humoral defense system.  In addition to this protection, our body has a cellular defense.  This is at the mucous lining level.  A body can stop an offending antigen as it enters your nasal passage or mouth for example, before it enters the bloodstream.  This protection is NOT measured by a titre.  So, if your pet has a low titre, that may increase his susceptibility to disease, but his cellular immunity could still afford him all the necessary protection.


Within the humoral defense are two levels:  sterilizing immunity and memory immunity.  If your pet has a high number of antibodies in the blood, it may be a sterilizing level.  This

means if he is exposed to the disease his body will neutralize it so easily, you won’t even know he was exposed!  If your pet has a low level of antibodies in the blood, it may be a memory level.  This means if he is exposed to the disease he may become somewhat ill, but will “remember” and fight and overcome the disease.


Thus, you should realize it is your pet’s immune response TO a vaccination, NOT the vaccination itself that protects your pet from disease.  There exists the phenomenon of no responders and low responders.  Some pets simply don’t respond to vaccination.  Some pets, even with repetitive vaccinations are low responders.  It is important to be aware if your pet is a poor responder.  You wouldn’t want to assume that just because your pet has been vaccinated that he is protected.  Many dog enthusiasts have heard of someone who has lost a pet to parvo even though the dog was vaccinated. 


There are many reasons for vaccination failure.  A titre is a blood draw that serves as one tool to assure you that your pet companion is protected.  Titre levels and recommendations based on them should be very individualized.  A pet’s lifestyle should be considered when making titre/vaccination recommendations. If your pet has a high titre, he does not need to be vaccinated with that antigen.  If he has a low titre despite a history of lots of exposure to that antigen, then another vaccination is not going to boost him any further.  In fact, repeating an unnecessary or ineffective vaccination could be harmful.


Vaccines have been associated with vomiting, diarrhea, fevers, rashes, anaphylaxis, vaccine site tumors, seizures and immune mediated disorders. A veterinarian who is experienced with utilizing titre information can provide you with guidance as to when to perform a titre and then based on that result, whether or not to boost. I recommend vaccinating puppies with distemper/hepatitis/parainfluenza/parvo at 8 and 12 weeks.  Do an in clinic titre at 16 weeks for rapid results.  It measures only distemper and parvo.  If it is positive for both then this means there is a sterilizing level of protection.  I then give the rabies vaccine.  If one or the other is negative there could still be adequate memory or even cellular immunity, however in a puppy who has not been over vaccinated, who has not had any reaction, and who could have had mother’s antibody present at time of prior vaccination, blocking the effectiveness of the vaccine, I would boost again with whichever individual vaccine was needed.


It is of notable interest that in hundreds of puppies/dogs on whom we performed hepatitis/adenovirus titre testing not one was unprotected.  Therefore we no longer test for this antibody level. At the dog’s annual wellness exam we perform a titre which delivers actual number results. This takes two weeks.  These results tell me if the pet’s prior vaccinations have stimulated the pet’s immune system to a degree that he has either memory or sterilizing immunity levels.  I decide based on the pet’s age, lifestyle, other disorders present, previous number of vaccines, guardian’s concerns about vaccine reactions, whether or not a booster is recommended. A technician calls the owner to report the results and recommendation.


The most a titre drops in one year is in half.  So depending on how high it starts the first time we check it, we can extrapolate and tell a client, a doggy day care, a boarding kennel, how often we feel a titre needs to be checked on an individual to assure that he is protected.  Some dogs are checked annually to satisfy a kennel requirement, others have NOT been checked NOR vaccinated for several years and then have still been found to have protective levels. Obviously, this saves the pet a lot of vaccine-associated risk and the client a lot of money.  Sometimes a new client whose pet has been vaccinated annually for many years receives his first titre test when older. Despite all that vaccine we determine he’s a low responder.  This tells us to stop vaccinating!  The client has been wasting money and taking unnecessary risk with his pet’s immune health.  That pet needs to be careful where he goes, what he sniffs and what he eats (i.e. other dog poo).


Specific canine titre parameters are as follows:
Michigan State University reports:

     CDV≥ 32                CPV≥ 80
     (Distemper)             (Parvo)
These levels would be considered protective. Roughly equivalent to sterilizing immunity.

Dr. Ron Schultz at the University of Wisconsin-Madison VMTH has explained that his research shows:
CDV≥ 4                 CPV≥ 20

May also be protective, but roughly equivalent to memory levels of immunity.


Specific feline titre parameters are as follows:

Michigan State:

CIV≥ 32          FVR≥ 16        FPV≥ 40

(Calici)       (Herpes/Rhino)   (Distemper/Panleukopenia)


Dr. Ron Schultz at the University of Wisconsin-Madison VMTH has explained that his research shows:

CIV≥ 4                    FVR≥ 2                     FPV≥ 8


Efficacy and legal guidelines for administration of rabies vaccine is based on duration of immunity to challenge studies, not on titre levels.  Therefore performance of titre testing for rabies protection does not yield useful results.  Keep in mind, vaccine manufacturers state that a vaccine should only be administered to ”healthy dogs and cats.”  Efficacy could be affected by “stress, weather, nutrition, disease, parasitism, concurrent treatments, individual idiosyncrasies or impaired immunological competency.”  Thus the administration of a vaccine does not guarantee protection.


Ask questions before you consent to the vaccination a pet with allergies, diabetes, otitis,
hypothyroidism, epilepsy, hyperadrenocorticism, kidney disease, cancer or other disease.