No increased risk for any autism subtypes
No increased risk associated with prenatal exposure
A new study published today in the journal “Pediatrics” indicated that there was no increased risk of Autism Spectrum Disorder associated with receipt of thimerosal-containing vaccines. The study also found no increased risk for any of the subtypes of Autism Spectrum Disorder, including ASD with regression. In addition, it found no increased risk of Autism Spectrum Disorder associated with prenatal exposure to thimerosal.
A case-control study was conducted in 3 managed care organizations of 256 children with ASD and 752 controls, matched by age and gender. Exposure to thimerosal was determined by electronic immunization registries, medical charts and parent interviews.
This study confirms previous research, which has not revealed an increased risk of autism associated with receipt of thimerosal containing vaccines. It adds to the body of knowledge by reporting that prenatal exposure to thimerosal is not associated with autism. It also looked specifically at subtypes of autism, including autism with regression, again finding no association with thimerosal exposure.
No significant differences in exposure effects were found between boys and girls for any of the ASD outcomes; there was no evidence that higher prenatal exposure exacerbated the effects of post-natal exposure; and there was no evidence that concurrent ethylmercury exposure was associated with ASD. In addition, there was no substantive difference in the association between thimerosal exposure and risk for ASD among children with an older sibling with autism and those without an older sibling with autism.
“In a way, it’d be great if thimerosal in infant vaccines was the culprit because the U.S. has already removed thimerosal from them” said Dr. Sharon Humiston, a pediatrician and FAAP, former member of the National Vaccine Advisory Committee (NVAC) and member of the Autism Science Foundation Science Advisory Board. “Because we have not found the root causes of autism, we need to keep funding the research that will help us find them. Because the resources to find what really does cause autism are scarce – money, scientists, and time – we urgently need to focus these resources on avenues that appear to be fruitful. The vaccine hypothesis just has not yielded answers that help my autistic son or my typically developing daughter who may want to have children of her own one day.”
Pediatrics, September 13, 2010: Prenatal and Infant Exposure toThimerosal From Vaccines and Immunoglobulins and Risk of Autism