Measles virus and Crohn's disease: a critical appraisal of the current literature.

The etiology of inflammatory bowel disease (IBD) is unknown. Recent reports in the literature have suggested that measles virus, both wild-type and vaccine-attenuated, might be a risk factor for Crohn's disease. We used the well-accepted Bradford-Hill criteria to evaluate the possible causal association between measles and IBD. Although the association may be biologically plausible, the literature lacks consistency, specificity, strength, and dose response. The current literature does not support an association between measles virus and IBD.