An update on vaccines and titer testing for dogs and cats

 An update on vaccines and titer testing for dogs and cats

Despite research showing that most vaccines have a much longer duration of immunity than originally thought, many veterinarians and their clients still opt for annual boosters. Find out how to break free of this mold and protect your dog or cat from over-vaccination.

The harmful effects of over-vaccination in dogs and cats is not a new topic. And if you’ve ever had an animal who reacted badly to too many vaccines, then you know it’s a real issue. Yet many conventional veterinarians still believe what they originally learned about vaccines, and promote annual boosters. In fact, yearly vaccination remains the single most common reason for annual check-ups or “wellness visits”. This article looks at the vaccines your dog or cat really needs, and how to help protect him from the harmful effects of over-vaccination through titer testing and other alternatives to conventional vaccine protocols.

Why annual boosters aren’t necessary

Discussions about the adverse effects of too many vaccines has been ongoing for decades, yet the newer knowledge is still considered controversial. Some veterinarians continue to tell their clients that there is no scientific evidence linking vaccinations with adverse effects and serious illness. Meanwhile, both pro-vaccine and anti-vaccine zealots abound with hysteria and misinformation, even though neither of these polarized views is helpful.

The truth is, when an adequate immune memory has already been established, there is little reason to introduce unnecessary antigen, adjuvant and other excipients (as well as preservatives) by administering booster vaccines. By measuring serum antibody titer levels triennially, or more often if needed, your veterinarian can assess whether a given animal’s humoral immune response has fallen below levels of adequate immune memory. In that event, an appropriate vaccine booster can be administered.

There is no such thing as an “up to date” or “due” vaccination. Enlightened veterinarians now offer a package of separated vaccine components, when available, rather than give them all together, since published data show more adverse reactions when multiple vaccines are administered at the same time.

Vaccine adjuvants increase risk of adverse events

Adding adjuvants to vaccines is intended to accelerate, prolong or enhance antigen-specific immune responses, thereby promoting their immunogenicity. However, this increases the risk of autoimmune and inflammatory adverse events. All licensed canine rabies vaccines still contain adjuvants, and most have thimerosal (mercury) or aluminum salts, whereas cats can receive a safer recombinant non-adjuvanted version. Importantly, killed inactivated vaccines containing adjuvants make up about 15% of the veterinary biologicals used, but have been associated with 85% of post-vaccination reactions.

Currently, particular attention is being focused on these heavy metal salts — thimerosal (mercury) and aluminum – being used in human and animal vaccines. Aluminum and mercury have recently been found in the brains of autistic people, and from vaccine adjuvants that cross the blood-brain barrier after injection and then persist lifelong. Clearly, there is an urgent need to remove heavy metals, like aluminum and mercury, from all vaccines, but especially from those given to human and animal neonates and infants.

Vaccination vs. immunization

While the act of vaccination may not equate to actual immunization, vaccinated and truly immunized animals should be fully protected from disease, as immune memory cell immunity persists lifelong.  Thus, giving boosters to immunized animals is unwise, as it introduces unnecessary antigen, excipient adjuvants, preservatives and other trace materials into their bodies.

In the intervening years between booster vaccinations, and in the case of geriatric pets, circulating humoral immunity can be evaluated by measuring serum vaccine antibody titers as an indication of the presence of immune memory. Titer tests do not distinguish between immunity generated by vaccination and/or exposure to the disease, although the magnitude of immunity produced solely by vaccination is usually lower.

Alternatives to conventional vaccine practices

As an alternative to annual boosters, and to help protect your dog or cat from vaccine-related adverse events, discuss the following alternatives with your veterinarian. If he or she dismisses your concerns and/or insists on annual vaccines, it’s time to look for another vet.

  • Measure serum antibody titer levels.
  • Avoid unnecessary vaccines or over-vaccinating (see below).
  • Separate highly antigenic vaccines such as rabies from others by at least ten days.
  • Use thimerosal-free rabies vaccines for dogs, and as late as legally allowed.
  • Use caution when vaccinating sick or febrile animals.
  • Tailor a specific minimal vaccine protocol for dog/cat breeds or families at risk for adverse reactions.
  • Start the vaccination series later (nine to ten weeks for a puppy; eight weeks for a kitten).
  • Avoid revaccination of an animal with a prior adverse event.

Be sure to watch your animal’s behavior and health after vaccination and alert your vet to any problems.

Vaccine titer testing

When doing titer (serum antibody) testing on your dog or cat, your veterinarian will assess the immunologic status of your animal against the common clinically-important infectious diseases, and determine if vaccine boosters are required or advisable. Protection is indicated by a positive titer result. Any measureable antibody level shows protection.

Once your dog or cat’s titer stabilizes, it should remain constant for many years. Titers are sustained unless he has a serious medical problem such as cancer, or receives high or prolonged doses of immune-suppressive drugs.

When determining a vaccine protocol for your dog or cat, it’s important to be able to dialogue with your veterinarian. By working with an enlightened vet, whether conventional, integrative or holistic, you can help ensure your animal remains protected from important infectious diseases without over-vaccination and the risk of adverse effects.

Which vaccines does your dog or cat truly need?


  • Modified live virus (MLV) or recombinant “core” vaccines (canine distemper, CDV; canine hepatitis, CAV-2; and canine parvovirus, CPV) preferably either at nine to ten and 14 to 16 weeks of age (minimum protocol); or at nine, 12 and 16 to 18 weeks of age. A bivalent CDV + CPV vaccine can be given instead, as preferred by this author.
  • For the optional bordetella or kennel cough vaccines, the oral version is preferred over the intranasal, although both offer more complete protection than the injectable version.
  • Leptospirosis vaccines protect against only four serovars of the organism. They are also second to rabies vaccines when it comes to hypersensitivity risk and other adverse effects. This vaccine should only be considered if leptospirosis is endemic in your area.
  • While canine influenza viruses (H3N2 and H3N8) are highly contagious, most infected dogs have mild to no clinical issues, unless they develop a high fever and are at risk for secondary pneumonia. Vaccination, while being widely promoted, is still optional.


  • Core vaccines (feline panleukopenia, FPV; feline calicivirus; feline rhinotracheitis/herpes) given as MLV or killed, inactivated or intranasal products are started in a two- or three-dose series beginning, for example, at seven to nine weeks of age and 12 to 16 weeks; or at seven, 11 and 16 weeks.
  • Some people consider feline leukemia virus (FeLV) vaccine important, especially among cats that live outdoors or are indoor/outdoor. Options are a recombinant non-adjuvanted or a killed adjuvanted vaccine.
  • Feline immune deficiency virus (FIV) vaccine is available in an adjuvanted killed virus vaccine for cats with an exposure risk similar to that of FeLV.
  • Other vaccines (chlamydia, feline infectious peritonitis (FIP)) are generally not recommended or are optional, and depend on circumstances and disease risk in your area.

Focus on rabies

The prevalence of reported rabies cases has been stable or decreasing for the past 15 years — except in bats, where it is increasing. For example, during 2015, about 100,000 samples were submitted for rabies diagnostics in the US, and 5,508 (5.6%) were positive. Of the positives, 92% cases were in wildlife (31% in bats, 29% in raccoons, 25% in skunks, 6% in foxes).  In dogs, the rate was 1%, in cats 4%, and in cattle 1.5%. In the first half of 2019, ten rabid bats have been identified in Los Angeles County, which is double the number for the same period in 2018. Approximately 38 rabid bats have been encountered each year in this county since 2011, which represents about 15% of the bats tested.

In Canada, meanwhile, the Canadian Food Inspection Agency tested 2,295 bat samples for rabies in 2015, and 151 (6.6%) were positive. This represented a 19.7% increase in the number of samples tested and a 62.4% increase over the number of positive bat samples tested in 2014.

Although the routine vaccination of domestic animals continues to be the mainstay in rabies control and prevention, the Rabies Challenge Fund is showing that the duration of immunity of rabies vaccines is longer than the one- or three-year revaccination protocol currently in use. Results show that:

  1. The duration of immunity to rabies in vaccinated dogs is at least five years.
  2. Immunologic memory exists even in vaccinated dogs with low rabies serum antibody titers.
  3. Non-adjuvanted recombinant rabies vaccines induced excellent antibody responses in previously vaccinated dogs 14 days after administration.

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