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2693 pages added, reviewed or updated during the last month (last updated: 14/4/2021)

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MMR and autism

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  • a paper by a team from the Royal Free Hospital reported on 12 children who appeared to have a new syndrome (1)
    • the age range of the children was 3-10 years
    • clinical findings in each case were varied
    • 11 of 12 children had patchy chronic colitis on colonoscopy
    • 7 children had ileal lymphoid hyperplasia on histological examination
    • there were severe behavioural and developmental disorders but no neurological abnormalities amongst the group of children
      • 9 children were autistic
      • 3 other children had severe developmental delay
      • in 8 of the cases, parents had linked the administration of the MMR vaccine to the child's behavioural disorder
    • the authors of the paper speculated that MMR vaccine may have had a role in the development of this syndrome; however autism often develops at approximately the age when the MMR vaccine is given
  • the authors speculated on a causal link between the bowel abnormalities and the developmental problems. However in almost all cases, the behavioural symptoms were apparent before any bowel symptoms were noted
    • the small number of cases and the problems of recall bias and ascertainment bias make the linking of the MMR vaccine to this syndrome speculative and unlikely to be causal

The Chief Medical Officer, after reviewing the current evidence, has concluded that there is no evidence to support suggestions that measles or MMR vaccines are implicated in Crohn's or autism. Also more recently a large population-based study involving 573,303 children with a follow up for a total of 2,129,864 person years concluded that the measles, mumps and rubella vaccine was not associated with autism (4).


  1. Wakefield AJ et al (1997), Lancet, 351, 637-41
  2. CSM (June 1999). Current Problems in Pharmacovigilance, 25, 9-12.
  3. Chief Medical Officer (27/3/98), PL/CMO/98/2
  4. Madsem KM et al (2002). A population-based study of measles, mumps, and rubella vaccination and autism. N Eng J Med, 347, 1477-82.

Last reviewed 01/2018