B’Lyme-y, should I vaccinate the dog or not?

(Or…all I want for Christmas is for somebody to tell me if I should advise vaccination for K9 Lyme disease)

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On the fairly long list of things the average veterinarian might request from the rosy cheeked & jolly one this holiday season, (after world peace and mandatory pet insurance plans), might be a wish for clear consensus on all things related to Canine Lyme disease.

Failing that, a definitive stance on one aspect, Lyme vaccination, would be kind’ve nice.

Well, Santa (or a team from the University of Guelph) and a sackful of PRISMA prepped systematic review, may have come a bit early this year. Since, seriously, nothin’ says Christmas like meta-analysis, eh? However, bear with me when I translate (likely poorly) that these types of terms reflect a solid attempt by this group of researchers to try and deliver to practicing veterinary clinicians (and pet-owners) a much-needed evidence-based assessment on a topic that doesn’t require a cup of cocoa or a simmering fire to get folks heated. 

Using defined inclusion and exclusion criteria, or a ‘what’s out and what’s in’ list to tackle assessment of studies that reported the use of Borrelia burgdorferi (the agent of Lyme disease) vaccines in dogs, the researchers started with 1570 studies. That seems like a lot…. but using their standardized criteria, they ended up with 3 observational (the most current dated 2005) and 13 challenge studies (with only 5 of the 13 (38%) done in the past 10 years, and all done in dogs < 18 m of age).  

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Don’t worry, I am getting to the holiday miracle (or epiphany) portion of this, i.e. should we (or should we not) consider Lyme vaccination effective? [Cue the little drummer boy] The summary of evidence completed by the researchers suggests that vaccination lowers the risk of clinical sign (lameness, anorexia, fever) development in vaccinated dogs vs. unvaccinated dogs.

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However, it is worthwhile (IMHO) to keep reading. [Cue the Grinch, get ready to have your heart shrink 2 sizes too small] As the article goes on to raise a number of concerns regarding study aspects frequently assumed when chatting about Lyme research, such as, were ticks infected with B. burgdorferi (i.e. did anyone check?), were dogs classified as negative before the study began (i.e. did anyone screen for B. burgdorferi status?), and ‘Are these articles relevant for the current vaccines (i.e. have vaccines changed over the years? And if so in what direction?’). Okay- I admit that last concern was mine.

Similarly, there was only one observational study that looked at clinical signs, and as the researchers quite rightly point out, clinical signs of Lyme disease are not all created equal…and this lack of information on clinical signs (individually or clumped together), their duration or severity is fairly critical (essential) for those of us attempting to make recommendations based on risks of clinical disease and with respect to prioritization of canine quality of life.

It is tough to weigh the pros and cons of a vaccine decision without having the questions the researchers outlined answered. However, I think this research team has earned a wassail (or at the very least a latke) for raising further awareness regarding the lack (and limitations) of studies on Lyme disease. Particularly the need for clinically focused studies (i.e. those performed in the field), as unfortunately, a disease model (along with a gold standard test) for B. burgdorferi and Lyme disease in dogs continues to remain on future ‘letters to Santa’ wish lists. 

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It’s going to require some serious sugarplums (or a nutcracker) to entice veterinarians to initiate and participate in broader based studies reflecting what occurs in general veterinary practise for many (most) K9 diseases and prevention strategies. And until this style of research occurs, I’ll assume that Santa is going to leave me (and my still unanswered question regarding Lyme vaccination) on his ‘naughty’ vs. ‘nice’ list.