California Study Finds No Link Between Autism, Vaccine Additive
There is no link between thimerosal, a vaccine preservative that contains mercury, and increasing cases of autism in California, according to a study published on Monday in the journal Archives of General Psychiatry, the Los Angeles Times reports.
The prevalence of autism continued to rise even after most vaccine manufacturers started to remove thimerosal, researchers found (Chong, Los Angeles Times, 1/8). Thimerosal has not been used in childhood vaccines since 2001, though it still is used in some flu shots.
For the study, researchers from the California Department of Public Health analyzed data from state-funded care centers for people with autism and other developmental disorders from 1995 to 2007. According to the study, 0.3 per 1,000 children born in 1993 had autism at age three, compared with 1.3 children per 1,000 born in 2003 (Chang, AP/Philadelphia Inquirer, 1/8).
The study also found that the autism rate in January 1995 was 0.6 per 1,000 births among children ages three to five, compared with 4.1 per 1,000 births in March 2007 for the same age group.
The researchers said that if there was a link between thimerosal and autism, the rates should have fallen in 2004, which is the first year children who received mercury-free vaccines would be entering the state health department's system care related to autism and other developmental disorders (Corbett Dooren, Wall Street Journal, 1/7).
The National Autism Association said that the study is flawed because some children might have been exposed to mercury through either flu shots or trace amounts in other vaccines. In addition, the group said that some vaccines containing thimerosal had expiration dates as late as 2005 and might have been used up to that date (Los Angeles Times, 1/8).
Robert Schechter, a medical officer at DPH and lead author of the study, said, "Whatever the explanation for this increase in children with autism, exposure to mercury in vaccines is not it," adding, "Vaccines with thimerosal and without have been safe and appropriate to give to our children" (Allday, San Francisco Chronicle, 1/8).
KPCC's "AirTalk" on Tuesday is scheduled to include a discussion about the study ("AirTalk" Web site, 1/8).
Broadcast information is available on the program's Web site. Audio of the segment will be available after the broadcast.