The study conducted by researchers from the state Department of Public Health and published in the January issue of the journal Archives of General Psychiatry is another evidence rejecting thimerosal exposure as a risk factor in autism. According to the Fresno Bee, doctors said the study "should reassure parents that the disorder is not caused by vaccinations."
The use of thimerosal in childhood vaccines was stopped in 2001, but was used in some flu shots. According to doctors, if the vaccine preservative was a risk, autism rates should have dropped between 2004 and 2007.
Fresnobee.com on Monday quoted Dr. Eric Fombonne, an autism researcher at Montreal Children's Hospital, as saying that the findings show "no evidence of mercury poisoning in autism" since there was no decline in autism rates even after the elimination of thimerosal.
Some groups and parents have complained that thimerosal impaired the ability of children with autism to socially interact and communicate. There are 5,000 cases seeking compensation lodged with the federal government.
The study analyzed a database of state-funded centers caring for people with autism and other developmental disorders. The researchers found that 0.3 per 1,000 children born in 1993 had autism at age three compared with 1.3 per 1,000 children born in 2003. Similar trends were found in other age groups.
The researchers said the findings are inconsistent with the hypothesis that exposure to thimerosal is a primary cause of autism in California.
The study, however, did not explore the cause of the rise in autism cases.
