CDC Studies on Vaccines and Autism Spectrum Disorders
Study
Description and Findings
Publication Date or
Estimated Date of
Publication
Denmark Measles-
Mumps-Rubella
(MMR)/Autism Study
CDC has an ongoing cooperative agreement with the Danish Medical Research Council. This
agreement supports collaboration with Danish researchers and gives CDC an opportunity to pursue
causes of birth defects and developmental disabilities through Denmark’s unique public health data
infrastructure. The Danish study, which followed more than 500,000 children for 7 years, found no
association between the MMR vaccination and autism. The results were published in the New England
Journal of Medicine (2002;347:1477-82).
November 2002
Thimerosal Screening
Study
The Vaccine Safety Datalink (VSD) was used to screen for possible associations between exposure to
vaccines containing thimerosal and a variety of renal, neurologic, and developmental problems. In the
first phase of this study, CDC used data from the two VSD managed care organizations (MCOs) with
automated outpatient data (where more subtle effects of mercury toxicity might be seen). The CDC and
VSD researchers found statistically significant associations between thimerosal and two
neurodevelopmental disorders—language delays and tics. However, the associations were weak and
were not consistent between the two MCOs. No association was shown with autism. In the second
phase of the study, CDC researchers looked at data from a third MCO with similar automated
vaccination and outpatient data to see if these findings could be repeated. Analyses using the same
methods as in the first two MCOs did not confirm results seen in the first phase. The results were
published in Pediatrics (2003;112:1039-48).
November 2003
Age at First MMR
Vaccination in Children
With Autism and
School Matched
Control Subjects: A
Population-Based
Study in Me