A link between the MMR vaccine and Crohn's disease, a lifelong inflammatory condition of the intestines, has been suggested. Earlier studies have refuted a link between the But until now there have been no similar studies investigating a link with Crohn's disease, writes Valerie Seagroatt from England's University of Oxford.
Seagroatt tracked Crohn's disease before and after the MMR vaccine was introduced in the U.K. in 1988, replacing the single measles vaccine. The vaccine was not associated with an increase in Crohn's disease in national hospital records, she says.
Studies like hers deserve caution because they don't rule out other influences, says Seagroatt. However, she says it's "highly unlikely" that something else accounted for her findings.
Seagroatt's findings appear in the May 14 issue of the British Medical Journal.
About Crohn's Disease
Crohn's is an inflammatory bowel disease. Its cause is not known, but genetic and environmental factors may both be involved. Smoking increases the risk of Crohn's disease. The main symptoms are abdominal pain, rectal bleeding, and diarrhea.
Medications and, in some cases, surgery can help manage the disease.
Seagroatt studied British hospital admission records from 1991-2003. She focused on people aged 18 and older who were admitted to hospitals for emergency treatment and had a main diagnosis of Crohn's disease. She then compared this data with rates of Crohn's disease before 1988.
She found no increase in Crohn's disease after the MMR vaccine was introduced in the U.K.
Seagroatt says there had been speculation that "infections with multiple viruses in the MMR vaccine might increase the risk of Crohn's disease." However, she says her study "provides strong evidence" that the vaccine "is no less safe in this respect than the single measles vaccine."
The single vaccine for measles had initially been associated with higher rates of Crohn's disease, but later studies didn't confirm that, says Seagroatt.