2018 ACVIM Forum Research Abstract Program: Seattle, Washington, June 14 - 15, 2018

Thirteen challenge trials and three observational studies were identified as eligible, and twelve challenge trials contained sufficient data to be included in our meta-analysis. A meta-analysis could not be performed for observational studies due to an insufficient number of studies. None of the challenge trials assessed lymphadenopathy, but for each of the remaining four clinical signs a separate random effects meta-analysis was performed. With the exception of anorexia, all summary odds ratios were less than the null value of 1. Overall, the findings of our meta-analysis suggest that North American Lyme vaccines reduce the odds of clinical illness in dogs following exposure to B. burgdorferi. However, these results should be interpreted with caution since a number of issues related to small sample size, study quality, and publication bias were identified. No experimental field trials were identified, highlighting a major gap in the literature on this topic.