MMR-autism link is clearly “busted”

Over at Aetiology, Jan Helldén mentioned a study:

“I would like to point everyone who believes that there is a connection between autism and vaccination to a Danish study that includes almost one tenth of the population. It was published in The New England Journal of Medicine in 2002 (KM Madsen, et al.: A Population-Based Study of Measles, Mumps, and Rubella Vaccination and Autism, NEMJ Vol. 347:1477-1482, No. 19). The abstract says it all.”


It has been suggested that vaccination against measles, mumps, and rubella (MMR) is a cause of autism.

We conducted a retrospective cohort study of all children born in Denmark from January 1991 through December 1998. The cohort was selected on the basis of data from the Danish Civil Registration System, which assigns a unique identification number to every live-born infant and new resident in Denmark. MMR-vaccination status was obtained from the Danish National Board of Health. Information on the children’s autism status was obtained from the Danish Psychiatric Central Register, which contains information on all diagnoses received by patients in psychiatric hospitals and outpatient clinics in Denmark. We obtained information on potential confounders from the Danish Medical Birth Registry, the National Hospital Registry, and Statistics Denmark.

Of the 537,303 children in the cohort (representing 2,129,864 person-years), 440,655 (82.0 percent) had received the MMR vaccine. We identified 316 children with a diagnosis of autistic disorder and 422 with a diagnosis of other autistic-spectrum disorders. After adjustment for potential confounders, the relative risk of autistic disorder in the group of vaccinated children, as compared with the unvaccinated group, was 0.92 (95 percent confidence interval, 0.68 to 1.24), and the relative risk of another autistic-spectrum disorder was 0.83 (95 percent confidence interval, 0.65 to 1.07). There was no association between the age at the time of vaccination, the time since vaccination, or the date of vaccination and the development of autistic disorder.

This study provides strong evidence against the hypothesis that MMR vaccination causes autism.

If I read this correctly, a vaccinated child has a 17% lower chance of getting an autism-spectrum disorder and an 8% lower chance of developing autism than one that is not vaccinated. In other words, vaccination seems to protect against autism. Interesting!

Thanks for the reference!


3 Responses to “MMR-autism link is clearly “busted””

  1. beebeeo Says:

    “If I read this correctly, a vaccinated child has a 17% lower chance of getting an autism-spectrum disorder and an 8% lower chance of developing autism than one that is not vaccinated.”
    No, you don’t read it correctly. If you look at the confidence intervals, they are too large to conclude that. The only conclusion is that there no statistically significant difference between the groups.

  2. micheleinmichigan Says:

    Connection is not causation. Just because in this study the group that are unvaccinated had a slightly higher rate of autism, it does not mean the vaccine provides some protection.

    The connection may be in the reason why the children didn’t receive the vaccine, allergies, seizures or other pre-existing medical conditions.

    Thanks for posting the study though. Good to see it rule out the connection of vaccines to autism.

  3. Tanto Bardianto Says:

    Thanks for the information friend

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