Study reports no link between thimerosal and neuropsychological outcomes

In what is sure to mark a new round in the debate regarding the impact of thimerosal in vaccines, a paper published in the latest issue of the New England Journal of Medicine reaches the following conclusion:

"Our study does not support a causal association between early exposure to mercury from thimerosal-containing vaccines and immune globulins and deficits in neuropsychological functioning at the age of 7 to 10 years."

The paper by CDC's William Thompson and (many) colleagues -- "Early Thimerosal Exposure and Neuropsychological Outcomes at 7 to 10 Years" -- is available for free at the NEJM website. The study compared children's performance on a battery of neuropsychological tests to their total exposures to thimerosal during vaccination as infants. The paper repeatedly states that autism was not a focus of this study, but there's little doubt that the findings here will find their way into the vaccines and autism debate, even despite efforts from CDC officials at today's teleconference to emphasize this distinction.

Tomorrow, we'll link to some of the media coverage that this news will surely receive -- it was already prominently featured on several of the national evening news broadcasts tonight. For now, here's coverage from the Associated Press, US News & World Report, and Reuters.

The New England Journal also published two related perspectives on thimerosal and vaccines. Paul Offit writes in "Thimerosal and Vaccines -- A Cautionary Tale" (free full text),

"The thimerosal controversy should stand as a cautionary tale of how not to communicate theoretical risks to the public; otherwise, the lesson inherent in the collateral damage caused by its precipitous removal will remain unlearned."

Stephen Sugarman also contributes a piece titled "Cases in Vaccine Court -- Legal Battles over Vaccines and Autism."

Autism advocates and proponents of a link between thimerosal and autism are already raising questions about the researchers, the study and its conclusions (despite the standards required for publication in the world's premier medical journal). For examples, here are statements from Autism Speaks and SafeMinds (which calls the study 'wrong').

More to come...