Court Weighs Autism-Vaccine Link
Perspective: Parents Sue Federal Government, but Do They Have a Case?
WebMD News Archive
June 11, 2007 -- Federal courts are now set to decide whether there is a
link between autism and childhood vaccines. But what do medical experts
Parents are suing the federal government, claiming that a preservative in
childhood vaccines led to autism in their children.
Typically, symptoms of autism are first noted by parents as their child
begins to have delays in speaking after age 1, around the same time a child
typically receives the MMR (measles-mumps-rubella) vaccine. This has led some
to suggest a link between the vaccine and autism.
What Is Autism?
Autism is a pervasive development
disorder (PDD), a group of illnesses that involve delays in the development
of many basic skills, most notably the ability to socialize or form
relationships with others as well as the ability to communicate and to use
imagination (including fantasy play). Children with these disorders often are
confused in their thinking and generally have problems understanding the world
In addition to problems with social interaction, imagination, and
communication, children with autism also have a limited range of interests.
Many children with autism (nearly 75%) also have mental retardation. In many
cases, children with autism are unable to emotionally bond with their parents
or other family members.
Is Thimerosal to Blame?
In years past, experts believed autism affected four to five out of every
10,000 children. But a new CDC report released earlier this year showed about
one in 150 8-year-old children had autism. Since that study involved just 14
states, it’s unclear if those numbers reflect national statistics.
If there is indeed a rise, what could be fueling this increase? The question
is whether this possible rise is due to doctors doing a better job at
identifying kids with autism or to some other reason.
What could that reason be? One theory is children’s vaccines. The MMR
vaccine - measles, mumps, and rubella -- has gotten the most attention, mainly
linked to the mercury-based preservative thimerosal.
Experts Say 'No'
Several medical studies have shown no link between autism and the MMR
vaccine. And several premier medical organizations have concluded that there is
no link between autism and thimerosal.
The CDC says there is no evidence to suggest a link. The Institute of
Medicine, a nonprofit, nongovernment organization, takes it one step further
and says the MMR vaccine absolutely does not cause autism.
Since 1999, when the American Academy of Pediatrics recommended that
thimerosal be taken out of vaccines as a precautionary measure, kids’ exposure
to the preservative has dropped significantly.
Thimerosal has been removed from or reduced to trace amounts in all vaccines
routinely recommended for children 6 years of age and younger. The exception is
the flu vaccine. A preservative-free version of the flu vaccine (contains trace
amounts of thimerosal) is available in limited supply for infants, children,
and pregnant women.
Some vaccines, such as the tetanus-diphtheria booster for older children and
adults, are also available in formulations that are free of thimerosal or
contain only trace amounts.