Why Vaccine Titers To Determine Vaccine Infectious Disease Protection Is A Bad Idea

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Antibodies, or immune messenger proteins that mark infectious disease organisms to be targeted by the immune system for removal, have gained a lot of attention in the age of COVID-19. From protection following infection to measurable antibodies created by vaccine, antibodies are the rage right now. They also have reignited client questions about running vaccine antibody titers in placed of the AVMA and AAHA established immunization protocols.

If titers told the whole immunology story as it pertains to protection, I would tell every client, “Sure, spend hundreds of dollars on vaccine titers every year instead of the vaccine you pay $20 for once every 3 years.” The problem is, antibodies, while an important marker of infectious disease protection, are one small cog in the wheel of immunity.

The truth is, the immune system is extremely complex, so much so that I spent 5 days week in immunology class for an entire semester in vet school and walked away with the basic functions and structure of the immune system, but realistically was left just scratching the surface of its depth and complexity. In reality, antibody titers tell part of the story, but other key aspects of immunity such as memory T-cells and an enormous cascade of immune messenger molecules tell the rest, making simple antibody titer a far less than perfect indicator of true immunity to an infectious disease.

This was displayed clearly in a research paper published in 1998 by renowned virologist and immunologist, Dr. Ronald Shultz, on the duration of protection of killed or modified live viral vaccines in dogs and cats, research that ultimately was in large measure the basis for vaccine reform in the early 2000’s by the AVMA and AAHA. The research studied not just duration of post vaccinal antibody, but also also duration of protection when challenged with the disease. The difference of antibody level versus real-life protection reported in the paper was very enlightening.

Canine distemper duration of immunity (DOI) varied considerably by strain.

  • Rockborn/snyderhill strain had a 15 year antibody DOI with a challenge DOI of 7 years.
  • Onderstepoort strain had a 9 year Antibody DOI with challenge DOI of 5 years
  • rCanine Distemper virus has a 3 year antibody DOI and a challenge DOI of 3 years

Rabies virus had a 7 year antibody DOI and a challenge DOI of 3 years.

From this research, it is clear that duration of antibody titers are substantially longer than challenge with the actual infectious disease, meaning that checking a titer that shows acceptable levels of antibody may not necessarily translate to real life protection.

A such, my stance on administration of vaccine boosters remains the same: the AVMA and AAHA adopted protocols of viral core vaccines boosted once every three years, and bacterin based vaccines administered yearly. Bacterin vaccines such as Leptospirosis and Lyme are less immuno-reactive and therefore are more short lived than modified live and kill viral vaccines.

Dr. Roger Welton is a practicing veterinarian and highly regarded media personality through a number of topics and platforms. He is the author of The Man In The White Coat: A Veterinarian’s Tail Of Love. In addition to being passionate about integrative veterinary medicine for which he is a globally recognized expert, Dr. Welton was also an accomplished college lacrosse player and remains to this day very involved in the sport.  He is president of Maybeck Animal Hospital , general partner of Grant Animal Clinic, and runs the successful veterinary/animal health  blogs Web-DVM and Dr. Roger’s Holistic Veterinary Care.  Dr. Welton fulfills his passion for lacrosse through his lacrosse and sport blog, The Creator’s Game.

Article Sourse, Duration of Immunity for Canine and Feline Vaccines: A Review

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