News roundup

Study shows no link between MMR vaccination and autism

London Susan Mayor

The measles, mumps, and rubella vaccine (MMR vaccine) is not associated with increased risk of pervasive developmental disorders—including autism—according to a case-control study that has confirmed the findings of previous studies (Lancet 2004;364:963-9).

The case-control study used the UK general practice research database—a large database of patients’ electronic clinical records—to identify 1294 people born in 1973 or later who had been diagnosed as having a pervasive developmental disorder recorded between 1987 and 2001. Full medical records—including hospital clinic letters and specialist reports—were checked for more than 300 of these people, and the diagnosis was confirmed in more than 90% of the group. They were matched to controls who did not develop this type of disorder, based on age, sex, and general practice.

Results showed that 78% (1010/1294) of cases, who were diagnosed with pervasive development disorder, had been given the MMR vaccine, but a higher proportion (3671; 82%) of controls, without such a disorder, had been given the vaccine.

The odds ratio for association between having the MMR vaccine and having a pervasive development disorder was 0.86 (95% confidence interval 0.68 to 1.09), indicating no relationship. Findings were similar when restricted to children diagnosed with autism, to children vaccinated before their 3rd birthday, or to the period before media coverage in 1998 of the hypothesis linking the MMR vaccine with autism.

One of the researchers, Liam Smeeth, senior lecturer in clinical epidemiology at the London School of Hygiene and Tropical Medicine, London, said, "We found no convincing evidence that MMR vaccination increases the risk of autism or other pervasive developmental disorders." He considered that the strengths of the study included its large size—more than 1000 cases of pervasive developmental disorder—and the use of population based data.

Vaccination was recorded before the date of diagnosis, so there was no scope for recall bias. In addition, the study allowed examination of data recorded before the hypothesis that MMR increased the risk of autism had been proposed.

The study, funded by the UK Medical Research Council, showed a similar lack of association between MMR vaccination and autism as previous studies in the United States and Scandinavia, based on systematic review. Dr Smeeth reported, "A pooled estimate of all of these studies—carried out in different settings—showed no link between MMR and autism. We can now move on and look for the real causes of autism."

He considered that the focus on MMR and autism had potentially hampered research into pervasive developmental disorders: "These are severe diseases for which very little is known about causation; this absence of knowledge might itself have contributed to the misplaced emphasis on MMR as a cause. Research into the real origins of autism is urgently needed."
 

Rapid Responses:

Read all Rapid Responses

"We can now move on..." Oh no you don't Prof Smeeth!

John Stone
bmj.com, 17 Sep 2004 [Full text]

Same old, same old..

Jamie S Robertson
bmj.com, 17 Sep 2004 [Full text]

IS THERE ANYBODY THERE?

John Stone
bmj.com, 19 Sep 2004 [Full text]

Environmental reasons for increases in autism

Ellen c G Grant
bmj.com, 19 Sep 2004 [Full text]

Re: IS THERE ANYBODY THERE?

Adam Jacobs
bmj.com, 20 Sep 2004 [Full text]

Adam Jacobs' response

John Stone
bmj.com, 20 Sep 2004 [Full text]

The Bigger They Are…

F. Edward Yazbak
bmj.com, 20 Sep 2004 [Full text]

Danish MMR study

Hilary L Davidson
bmj.com, 20 Sep 2004 [Full text]

Re: Danish MMR study

Adam Jacobs
bmj.com, 22 Sep 2004 [Full text]

Re: Danish MMR study

John Stone
bmj.com, 22 Sep 2004 [Full text]

Re: Re: Danish MMR study

L. Travis Haws
bmj.com, 22 Sep 2004 [Full text]

Re: Re: Re: Danish MMR study

Adam Jacobs
bmj.com, 23 Sep 2004 [Full text]

Re: Re: Re: Re: Danish MMR study

L. Travis Haws
bmj.com, 24 Sep 2004 [Full text]

Re: Re: Re: Re: Re: Danish MMR study

Adam Jacobs
bmj.com, 24 Sep 2004 [Full text]

GPRD case control with or without control control?

John P Heptonstall
bmj.com, 25 Sep 2004 [Full text]

Re: Danish MMR study

Graeme Johnston
bmj.com, 27 Sep 2004 [Full text]

Re: GPRD case control with or without control control?

Adam Jacobs
bmj.com, 27 Sep 2004 [Full text]

Re: Re: GPRD case control with or without control control?

John P. Heptonstall
bmj.com, 28 Sep 2004 [Full text]

Re: Re: GPRD case control with or without control control?

Carol Johnston
bmj.com, 28 Sep 2004 [Full text]

Re: Re: Re: GPRD case control with or without control control?

Adam Jacobs
bmj.com, 28 Sep 2004 [Full text]

Re: Re: Re: Re: GPRD case control with or without control control?

John P Heptonstall
bmj.com, 29 Sep 2004 [Full text]

Re: Danish MMR study

Raymond Gallup
bmj.com, 30 Sep 2004 [Full text]

Re: Re: Re: Re: Re: GPRD case control with or without control control?

Adam Jacobs
bmj.com, 30 Sep 2004 [Full text]

Re: Re: Re: Re: Re: Re: GPRD case control with or without control control?

John Stone
bmj.com, 30 Sep 2004 [Full text]

Re: Re: Re: Re: Re: Re: Re: GPRD case control with or without control control?

Adam Jacobs
bmj.com, 1 Oct 2004 [Full text]

Re: Re: Re: Re: Re: Re: Re: Re:

John Stone
bmj.com, 3 Oct 2004 [Full text]

Re: Re: Re: Re: Re: Re: GPRD case control with or without control control?

John P Heptonstall
bmj.com, 4 Oct 2004 [Full text]

John Stone's response

Adam Jacobs
bmj.com, 4 Oct 2004 [Full text]

Re: Re: Re: Re: Re: Re: Re: GPRD case control with or without control control?

Adam Jacobs
bmj.com, 4 Oct 2004 [Full text]

Re: Re: Re: Re: Re: Re: Re: Re: GPRD case control with or without control control?

John P Heptonstall
bmj.com, 4 Oct 2004 [Full text]

Re: John Stone's response

John Stone
bmj.com, 4 Oct 2004 [Full text]

Response to the two Johns

Adam Jacobs
bmj.com, 5 Oct 2004 [Full text]

Re: Response to the two Johns

John P Heptonstall
bmj.com, 5 Oct 2004 [Full text]

Re: Response to the two Johns

John Stone
bmj.com, 5 Oct 2004 [Full text]

Re: Re: Response to the two Johns

Adam Jacobs
bmj.com, 5 Oct 2004 [Full text]

Criticisms confounding Smeeth et al

John P Heptonstall
bmj.com, 7 Oct 2004 [Full text]

Out of time

John Stone
bmj.com, 7 Oct 2004 [Full text]

Re: Criticisms confounding Smeeth et al

John P Heptonstall
bmj.com, 9 Nov 2004 [Full text]

Re: Out of time (Adam Jacobs's interests)

John Stone
bmj.com, 12 Nov 2004 [Full text]

A letter the Lancet failed to publish

John Stone
bmj.com, 22 Dec 2004 [Full text]