MMR ( measles, mumps, and rubella ) vaccine does not seems to increase the risk of Crohn’s disease.

It has been hypothesised that the MMR vaccine increases the risk of autism and Crohn's disease.
Although a possible link with autism has been extensively studied and refuted, a link with Crohn's disease has not.

Valerie Seagroatt, from University of Oxford ( UK ), analysed data on hospital admissions for Crohn’s disease in children and adolescents over the 12 years from April 1991 to March 2003, in England.
She tracked Crohn's disease before and after the MMR vaccine was introduced in the U.K. in 1988, replacing the single measles vaccine.

There were 4463 admissions for Crohn's disease, 923 of which occurred in populations with a vaccination rate of 84% ( those born in 1988-9 or later ).
Although the age specific rates increased over the study period, no obvious changes occurred that coincided with the introduction of MMR vaccine.
The estimated rate ratio for the MMR vaccination programme ( rates in populations with a vaccination rate of 84% compared with those with a rate of 7% ) was 0.95 .

” The introduction of MMR vaccine, replacing the single measles vaccine, was not associated with an increase in Crohn's disease,” says Seagroatt. “ Given the precision of the rate ratio, all but a small risk would have been detected. This was an ecological study, and findings from such studies generally need to be treated cautiously because of potential for confounding. Could the negative finding from this analysis be due to confounding? If so, some factor(s) would have to be negatively associated with Crohn's disease, be introduced over the same three year period, and be targeted at the same population of infants as MMR vaccine to mask a true association. This seems highly unlikely. “

Source: British Medical Journal, 2005


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