Research that has identified an increased risk of autism with thimerosal-containing vaccines ‘have significant methodological limitations,’ the agency said.
The Centers for Disease Control and Prevention on June 24 said there is no link between vaccines containing a preservative called thimerosal and autism. The statement comes two days before a meeting in which new advisers to the agency will consider whether to recommend restricting thimerosal-containing influenza vaccines.
Thimerosal is a preservative that is 50 percent mercury, by weight, It began being used in vaccines in the 1930s.
Data, including from the CDC Vaccine Safety Datalink system, show no association between exposure to thimerosal and autism spectrum disorder, CDC staffers wrote in a 17-page document that was later taken offline.
While other papers have found an increased risk of autism and neurodevelopment disorders from vaccines with thimerosal, those studies “have significant methodological limitations including unmeasured confounding, inaccurate assessment of exposures, differences in control and case groups, unverified diagnoses, and other potential biases that threaten the validity and reliability of the findings,” the document states.
It added that in light of “the breadth of evidence and consistency in results from multiple population-based studies conducted in several countries with various study designs, the evidence does not support an association between thimerosal-containing vaccines and autism spectrum disorder or other neurodevelopmental disorders.”
On June 24, Vivien Dugan, a CDC scientist, is slated to present the review and its conclusions to the Advisory Committee on Immunization Practices (ACIP), an outside panel that advises the CDC on vaccines.
The committee will also hear from nurse Lyn Redwood about thimerosal, and influenza vaccines containing the preservative.
One of Redwood’s presentations highlights studies such as a 2000 paper that found infants who received hepatitis B vaccines with thimerosal had a jump in mercury levels following vaccination, and states that “removing a known neurotoxin from being injected into our most vulnerable populations is a good place to start with Making America Healthy Again.”
Redwood is the co-author of papers about mercury and autism, including a 2004 paper that says thimerosal could cause autism.
