The Autism — MMR Vaccine Connection
From the April 2001 Early Childhood newsletter.
Since 1998, much has been said and speculated about a possible connection between the measles-mumps-rubella (MMR) vaccine and autism. That year, British physician Andrew Wakefield first proposed a link between the two after he observed autism symptoms in children who had recently received the vaccine. According to a recent article in the "San Francisco Chronicle," he also speculated a connection between increases in autism cases in California and an increased use of the vaccine there.
Loring Dales, a medical epidemiologist in the immunization branch of the California Health Department, recently co-authored a study that appeared in the March 7, 2001 issue of the "Journal of the American Medical Association" that refutes the autism-MMR vaccine connection. Using the state health department's data, researchers looked at the number of children born between 1980 and 1994 who were diagnosed with autism and then examined the number of children who received the MMR vaccine during that time. Dr. Dales reported that, while the study found increases in the number of children diagnosed with autism over that time period, there was no substantial increase in the number of children receiving the vaccine.
Dr. Dales also pointed out that the chemical make-up of the vaccine did not change during that time period, ruling out the possibility that a change in the vaccine could account for the increase in autism cases. After considering all of the data, Dr. Dales emphasized that there is no connection between the use of the MMR vaccine and autism. He also noted that results of a recent British study on the same subject were identical to those found in California.
One of the reasons the MMR vaccine may have been thought to be linked with autism, noted Dr. Dales, is that children begin to show signs of autism at around the age — 18 months — they are given the MMR vaccine. Other reasons for the increase in autism cases have been proposed, but research is ongoing. Dr. Dales emphasized the need for more research into the causes of autism but clearly stated, "We now know the MMR vaccine is not one of them."
Dr. Dales's department began the study in response to calls from pediatricians' offices reporting heightened parental concern over the MMR vaccine. When asked about the advice he would give to parents, Dr. Dales, who has a young grandchild, emphatically stated, "It's impossible that MMR could have caused the increase [in the numbers of autism cases]. Children should take this vaccine."
