Specifically, the committee addressed two specific vaccine related issues:

1. Was there scientific evidence that the MMR (measles-mumps-rubella) vaccine caused autism?
2. Did vaccines containing the preservative thimerosal cause neurodevelopmental disorders, such as autism, attention deficit disorder (ADHD) and speech or language delays?

Autism is a chronic developmental disorder characterized by problems in social interaction, communication, and restrictive and repetitive interests and activities. The condition may be initially noted in infancy as impaired attachment, but it is most often first identified in toddlers, mostly boys, from 18 to 30 months of age. Boys are 3 to 4 times more likely to be afflicted with autism than girls. Thimerosal is an organic mercury compound that is still used as a preservative in some adult vaccines. It began to be removed from vaccines for children in 1999. Today, with the exception of some Influenza (flu) vaccines, none of the vaccines used in the United States to protect preschool children against 12 infectious diseases contain thimerosal as a preservative.

Characteristics of Children with Autism Click here

Considerable debate has brewed for years as to whether the measles-mumps-rubella vaccine and thimerosal might trigger the onset of autism in small children. This began in 1998 when an article appeared in the British medical journal Lancet that described 12 children with neurodevelopmental delays (eight with autism) who developed their condition within one month of receiving the MMR (measles-mumps-rubella) vaccine.

A year later, Cable News Network (CNN) broadcasted a program on which the parents of a 3-year old stated he had developed autism two weeks after receiving measles, mumps and rubella (MMR) vaccine. While an American Academy of Pediatrics official was interviewed and indicated that there was no scientific evidence that a link exists between autism and vaccination, the dramatic before-and-after videotapes of the child had enough impact to persuade many parents to avoid having their children vaccinated. The program's narrator added fuel to this controversy by stating that there had been "a puzzling jump in the number of children being diagnosed with autism."

Soon parents began refusing to have their children receive the measles-mumps-rubella vaccine and public health officials became concerned that a measles epidemic was becoming increasingly possible. This is when the government, as well as other health organizations, decided to have the Institute of Medicine look into the controversy and come up with their recommendations.

The committee’s report issued in May of 2004, concluded neither the mercury based vaccine preservative thimerosal nor the measles mumps rubella (MMR) vaccine were associated with autism. Furthermore, the hypotheses that the MMR vaccine and thimerosal could trigger autism lacked supporting evidence.

"The overwhelming evidence from several well-designed studies indicates that childhood vaccines are not associated with autism," said Committee Chair Marie McCormick, Sumner and Esther Feldberg Professor of Maternal and Child Health, Harvard School of Public Health, Boston. "We strongly support ongoing research to discover the cause or causes of this devastating disorder. Resources would be used most effectively if they were directed toward those avenues of inquiry that offer the greatest promise for answers. Without supporting evidence, the vaccine hypothesis does not hold such promise."

Conclusion: Is there a link between measles vaccination and autism?

• No, there is no scientifically proven link between measles vaccination and autism.
  
• The benefits of recommended childhood vaccines are proven. Thanks to vaccines, few children in the United States are harmed by measles, polio, tetanus and other serious vaccine-preventable diseases. Immunization against measles has led to a dramatic decrease in the incidence of measles, which is sometimes fatal. Those grandparents who still remember the horrors of measles, mumps and rubella in the United States know that the importance of this immunization cannot be overestimated.
  
• Extensive reports from both the American Academy of Pediatrics, the Institute of Medicine and the Centers for Disease Control and Prevention conclude that there is no proven association between Measles-Mumps-Rubella (MMR) vaccine and autism.
  
• Autism is a chronic developmental disorder, often first identified in toddlers from age 18 months to 30 months. MMR is administered just before the peak age of onset of autism. This timing leads some parents to mistakenly assume a relationship. There is no evidence that MMR causes autism.
  
• While the known number of autism cases has been increasing since 1979, there was no jump after the introduction of MMR vaccine in 1988.
  
• Increasing evidence indicates that autism is determined while the baby is still in the womb, early in the pregnancy. The fact that autism is diagnosed during the second or third year of life does not mean that it began at that age. Analyses of home movies made from birth onward have shown that most children who are diagnosed as autistic during the second or third year have abnormal signs during the first year -- and some even show abnormalities at birth.
  
• The current theory favored by many experts is that autism is a genetically-based disorder that occurs before birth. Studies of persons with autism are finding abnormalities in brain structures that develop in the first few weeks of fetal development.
  

The Institute of Medicine report should provide parents reassurance that the vaccines their children are receiving are indeed safe, and that mechanisms to monitor and ensure the continued safety of vaccines in the United States are working.