Field: Medicine › EpidemiologyType: Couldn't replicate a published resultArea: autism spectrum disorderTarget: Measles virus RNA in bowel tissue after MMR vaccinationStage: replication
Hypothesis
Children with autism and bowel problems would carry measles virus RNA in their bowel tissue more often than children with bowel problems alone, as a 1998 report suggested.
What failed
In bowel tissue from 25 children with autism and bowel problems and 13 controls, tested blind in three laboratories (including the original one), measles virus RNA did not differ between groups. Onset of autism and bowel symptoms was not related to the timing of the MMR vaccine.
Broken assumption
Persistent measles virus from the MMR vaccine in the bowel is linked to autism.
Why
The original finding did not reproduce when tested with the same design in blinded laboratories.
From the published paper: Hornig et al. PLoS ONE, 2008. ↗Public domain