Apparent Lack of Association between Primary Immune-Mediated Thrombocytopenia and Recent Vaccination in Dogs
A.A. Huang; J. Coe; G.E. Moore; J.C. Scott-Moncrieff
I’ve written about the proposed association of vaccination and immune-mediated diseases, in particular immune-mediated hemolytic anemia (destruction of red blood cells). For that disease, the evidence is contradictory, and in general it seems likely that very rare cases of immune-mediated disease are triggered by vaccination, but this is not a common or widespread problem, and the vast majority of cases occur from natural exposure to triggers in the environment, probably in dogs with a genetic susceptibility since there are breed predilections.
This study looked for an association between vaccination and immune-mediated thromboctopenia (ITP, the destruction of platelets, necessary for blood clotting). Looking back through medical records at dogs diagnosed with ITP and then comparing them to dogs of similar age, sex, and breed with other diseases, the authors did not find that vaccination increased the odds of developing ITP.
Again, all the usual caveats about small, retrospective, case-controlled studies apply, so these results cannot be viewed as the final word on the question. But even this qualified evidence is more reliable than the wild guesses, hunches, and clinical impressions of those who confidently blame vaccines for diseases like ITP.