Autism and the MMR Vaccine Connection : Part 2

by National Institute of Health

(Page 2 of 3)

In 1999, Taylor and colleagues published a study that argued against the suggested link between autism and the MMR vaccine suggested in the Wakefield study. Taylor's study looked at all the known cases of ASD in children living in certain districts of London who were born in 1979, or later. Researchers then matched the ASD patients with an independent registry of vaccinations. The results of this study showed that:

The number of ASD cases had increased steadily since 1979, but there was no sharp increase in the number of cases after doctors started using the MMR vaccine in 1988.

Children showed symptoms of ASD and were diagnosed with ASD at the same ages, regardless of whether they were vaccinated before or after 18 months of age. This finding is important because if the MMR vaccine caused ASD, the children who were vaccinated earlier would show symptoms earlier.

By age two, vaccination coverage (the number of children who received vaccines) among children with ASD was nearly the same as vaccination coverage for children the same age who did not have ASD throughout the region. If the MMR vaccine and ASD autism were linked, then a greater number of children who had been vaccinated throughout the region would have ASD.

The first signs of autistic behavior or first diagnosis of ASD was not more likely to occur in time periods following the MMR vaccine than in other time periods.

Also in 1999, the United Kingdom's Committee on Safety of Medicine examined hundreds of reports collected by lawyers of patients with autism and similar disorders that families said they developed after receiving the MMR or MR vaccine. After a systematic, standardized review of the case information, the Committee found that the information did not support any link between vaccines and autism. Based on the evidence, the Committee concluded that there was no cause for concern about the safety of MMR or MR vaccines.

A study, done in Sweden in 1998, also showed no evidence of association between the MMR vaccine and autism. The study compared the number of autism cases in children from two Swedish towns before 1982, when local doctors first started using the MMR vaccine, and after 1982. The results showed no difference in the rate of autism between the two groups of children in either town.

Another study, done in England in 1997, looked at any possible link between the measles-specific vaccine (one part of the MMR vaccine) and different problems that result from damage to the nervous system, such as learning disabilities and behavior problems. These researchers found no proof that the measles vaccine was in any way linked to long-term damage to the nervous system.

Is there any research going on to find out if the MMR vaccine is linked to autism?

The NIH is doing a number of things to look into the claims about MMR vaccines and autism:

The Network on the Neurobiology and Genetics of Autism: Collaborative Programs of Excellence in Autism (CPEA), funded by the NICHD and the National Institute on Deafness and Other Communication Disorders (NIDCD), with additional funding from the CDC, are working together to study autism and the MMR vaccine. This research will examine people diagnosed with autism who seemed to develop normally, but then started to show autistic symptoms. This type of situation is called "regression." To learn as much as possible about these patients, researchers will compare them to people who do not have autism, and to people who showed autistic symptoms since birth, called classic autism. CPEA researchers will compare vaccination records to see if the onset of autism was associated with receipt of MMR and other vaccines. Lab tests will then look for any evidence of persistent infections that could be related to the MMR vaccine.

The NICHD is also working with other NIH Institutes, the CDC, the Environmental Protection Agency (EPA), and other federal agencies to conduct a large, long-term study of the effects of the environment on children's health. This study will follow 100,000 children from before birth to age 20, to track their growth and development, as well as their genetic blueprints and environmental factors that they encounter. Researchers hope to establish or rule out links between a variety of environmental events and normal and abnormal development, such as autism, asthma, and other childhood disorders that have shown dramatic increase. The study is currently under design.

Another NIH Institute, the National Institute of Neurological Disorders and Stroke (NINDS) is also conducting a retrospective case-control study to identify any molecular markers in neonatal blood of children with autism, with support from the California Department of Health Services and the Division of Bioengineering and Physical Science (DBEPS) at the NIH.

About the Author

NIH is the nation's medical research agency - making important medical discoveries that improve health and save lives. The National Institutes of Health (NIH), a part of the U.S. Department of Health and Human Services, is the primary Federal agency for conducting and supporting medical research.