Rabies Vax Study Summary Rabies Challenge Fund
A study conducted according to the USDA Title 9 canine vaccine licensing standard, was begun more than five years ago. The purpose was to determine if the duration of immunity from commercially available rabies vaccines was longer than 3 years, with the goal of extending state-mandated rabies boosters for dogs to 5, and then 7 years. The first rabies vaccine studied was selected based on the superior response it provided in the USDA challenge trials for licensing. Another licensed rabies vaccine was administered to a second, separate group of dogs 2 years after the first study began so that a minimum of two commercially available rabies vaccines would be tested. The second vaccine selected is the one currently administered to a very high percentage of dogs. Both vaccines demonstrated excellent protection based on antibody testing for each of the first three study years. However, fewer than 30% of dogs in the first vaccine group, now five years since vaccination, had serum rabies antibody titer levels considered positive on the Rapid Fluorescent Focus Inhibition Test (RFFIT). (Note: RFFIT is the rabies titer standard established by the Centers for Disease Control within the USA [0.1 IU/mL] and the World Health Organization [0.5 IU/mL] for export to other rabies-free locations to be adequate to protect humans, not dogs, against rabies. There is no established standard for dogs, which means that the human standards must be extrapolated when assessing protection for other species.) Some of the dogs with low or no detected RFFIT antibody were further tested to determine if they had “immunologic memory”. This in vitro test shows whether memory is present or not, even in cases when serum antibody cannot be detected at a level considered to be protective. The results of this further testing indicated that most of the dogs vaccinated five years ago, even without a positive RFFIT, do have “immunologic memory”. As soon as a USDA licensed facility can be reserved, we plan to challenge some of those dogs with rabies virus to determine if the memory response demonstrated actually correlates with protection. Our conclusion from studies with the initial rabies vaccine is that the immunity conferred by that product, and assessed by the in vitro RFFIT, was excellent for the first three years, but declined during the fourth year, and continued to drop during the fifth year. The second vaccine group, which is now three years from vaccination, will remain on study for at least two more years. Principal Investigator, Dr. Ronald Schultz of the University of Wisconsin School of Veterinary Medicine, is preparing results of the study and details described above for scientific peer review and publication. That data will be made available to the public as soon as our paper has been accepted for publication. After completion of the peer-review process, it is our hope that this data will establish the world’s first canine rabies titer standard. If this data is further verified by challenge, it will provide a solid scientific base enabling states to incorporate titer clauses into their laws. PERMISSION GRANTED TO CROSS-POST |
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| interesting. The problem with waiting more than 3 years is many owners simply will not return. I know I forget and have to check the tags to remember. Of course the vet sends out reminders, but what if I have moved? How many owners would bother? Yes, everyone here, but the average pet owner doesn't care for their pet, keeping track of details. Don't get me wrong, I fully support reducing unnecessary vaxs for the dog's health, just many owners are lazy. |
SheepieBoss wrote: interesting. The problem with waiting more than 3 years is many owners simply will not return. You nailed it! This was one of our biggest issues when I worked as a vet tech. And the issue is two-fold. Leaving aside the long-term effectiveness of the vaccine (which this study looks to be addressing), the second issue is a legal one. An animal that is just one day overdue for it's rabies vaccination is legally considered to be unvaccinated. At our hospital we had three instances over the course of 5 years where we had to quarantine an animal in hospital for 6 months (the regulation in Delaware at that time) because they were bitten after their vaccination due date, and the animal that bit them was not captured and tested. We were not allowed to update their vaccination until the quarantine period was over. Worse, though, is the sheer stress of the quarantine. I won't get into the medical debate on vaccinations. But we live with lots of wildlife - coyote, 'possums, raccoons, chipmunks, squirrels, skunks - so I don't want to risk a stressful quarantine for my girl on a technicality. |
| Thanks Kris for the update! I was actually wondering where we were on the timeline, and what the results were showing. |
got sheep wrote: Thanks Kris for the update! I was actually wondering where we were on the timeline, and what the results were showing. We're far from being done, but the serological work is in on the first batch of dogs and we wanted to update the public. For me, personally, the possibility of establishing the world's first canine rabies titer standard after the peer-review process is the most important aspect of the studies. |
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