Beginning in 1998, Andrew Wakefield proposed the hypothesis that being vaccinated against measles contributed to autism, including identifying a new syndrome, "autistic enterocolitis",  in which autism was in part gastrointestinal inflammation caused by vaccination against measles.  His research was roundly debunked, and the majority of his co-authors retracted their contributions.

However, belief in the vaccination-autism connection lived on.   A case study, repeating Wakefield's method of sampling gut tissue, has just been published in the Public Library of Science journal, PLOS-One.

This study provides strong evidence against association of autism with persistent MV RNA in the GI tract or MMR exposure. Autism with GI disturbances is associated with elevated rates of regression in language or other skills and may represent an endophenotype distinct from other ASD.

Predictably, anti-vaccination activists and those who insist that vaccination does too cause autism are decrying the study.

Citation: Hornig M, Briese T, Buie T, Bauman ML, Lauwers G, et al. (2008) Lack of Association between Measles Virus Vaccine and Autism with Enteropathy: A Case-Control Study. PLoS ONE 3(9): e3140. doi:10.1371/journal.pone.0003140

Previously:

MMR and Autism: No Link at All--How The World Was Hoodwinked by Wakefield

Elsewhere:
The Great Beyond
LeftBrain/RightBrain
One Dad's Opinion
Respectful Insolence
Aetiology
Scientific American