Scientists don’t know exactly what causes autism at this time. 

Much evidence supports the idea that genetic factors—that is, genes, their function, and their interactions—are one of the main underlying causes of ASDs. But, researchers aren’t looking for just one gene. Current evidence suggests that as many as 10 or more genes on different chromosomes may be involved in autism, to different degrees.

Some genes may place a person at greater risk for autism, called susceptibility. Other genes may cause specific symptoms or determine how severe those symptoms are. Or, genes with changes or mutations might add to the symptoms of autism because the genes or gene products aren’t working properly.

Research has also shown that environmental factors, such as viruses, may also play a role in causing autism. 
While some researchers are examining genes and environmental factors, other researchers are looking at possible neurological, infectious, metabolic, and immunologic factors that may be involved in autism.

Because the disorder is so complex, and because no two people with autism are exactly alike, autism is probably the result of many causes. 

Is there a link between autism and vaccines?

To date, there is no conclusive scientific evidence that any part of a vaccine or any combination of vaccines causes autism, even though researchers have carried out many studies to answer this important question. There is also no proof that any material used to make or preserve vaccines plays a role in causing autism. 

Although there have been reports of studies that relate vaccines to autism, the findings have not held up under further investigation. Researchers have been unable to replicate the studies that reportedly found a link between autism and vaccines.

There is a great deal of research and discussion on the topic of vaccines and autism—too much to cover here. The U.S. Centers for Disease Control and Prevention (CDC) conducts and supports most of the federal epidemiological studies that seek to answer questions about vaccines and autism. 

Currently, the CDC provides the most accurate and up-to-date information about research on autism and vaccine research, both supported by the federal government and funded independently. 

For more information, visit http://www.cdc.gov/vaccinesafety/. 

Publish Date: 05/03/2005

Page 4

  home | previous | next | last