(January 7, 2008 - Insidermedicine) Removing the mercury-containing preservative thimerosal from vaccines has done nothing to stem the increasing rates of autism and related disorders in California, according to research published in the Archives of General Psychiatry.

Here are some facts about autism and its link with vaccines:

•    Autism is a lifelong brain disorder that affects three crucial areas of development: communication, social interaction, and creative or imaginative play.

•  The presence of any of the following signs should prompt further evaluation for autism:

No babbling by 12 months.
No gesturing such as pointing or waving goodbye by 12 months.
No single words by 16 months.
No two-word spontaneous phrases  by 24 months.
Any loss of any language or social skills, at any age.
The American Academy of Pediatrics recommends that all children be screened for autism at the 18- and 24-month well-child doctor visits, using autism-specific formal screening tests.

•    The preservative agent thimerosal, which contains the known neurotoxin mercury, was once suspected to be a contributing factor to increasing rates of autism. Thimerosal was removed from most vaccines in 2001.

Researchers from the California Department of Public Health used government records to explore changes in the rates of autism between 1995 and 2007. They wanted to see whether taking thimerosal out of vaccines has had an impact.

Overall, the proportion of children with autism has been steadily increasing since 1995, even after thimerosal was removed from vaccines. Only 0.3 per 1,000 children born in 1993 had autism at age 3. This proportion jumped to 1.3 per 1,000 among those born in 2003. Among children aged 3 to 5, the prevalence of autism increased from 0.6 per 1,000 in live births in January 1995 to 4.1 per 1,000 in March 2007.

Experts still do not know why rates of autism are increasing. Today's research demonstrates that exposure to thimerosal in vaccines does not appear to play a role. The researchers recommend a continued search for other possible contributors to the risk of developing autism, especially contributors that can be modified.

For Insidermedicine in Depth, I'm Dr. Susan Sharma.