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Did CDC Conspire to Hide Vaccine Risk?

'Simpsonwood Conspiracy' Claims Debunked; Concerns Remain
WebMD Health News
Reviewed by Laura J. Martin, MD

Did the CDC conspire with vaccine advocates to hide evidence that children get autism from mercury in vaccines?

The claim was made most forcefully by Robert F. Kennedy Jr. in a 2005 article published in print by Rolling Stone and online by Salon, and in what Kennedy called an "original research paper" on his web site.

It's a terrific story: A cabal of scientists corrupted by pharmaceutical company cash meets secretly at a wooded enclave outside Atlanta called Simpsonwood to hide convincing evidence that autism is caused by a mercury-based vaccine preservative called thimerosal.

Kennedy, after obtaining a verbatim transcript of the conference, reveals the CDC plot. "If, as the evidence suggests, our public health authorities knowingly allowed the pharmaceutical industry to poison an entire generation of American children, their actions arguably constitute one of the biggest scandals in the annals of American medicine," Kennedy concluded.

It's such a good story, it's still frightening parents seeking information on vaccine safety -- even though by January 2011 the article had been withdrawn by both publishers and removed from their web sites.

Salon published five corrections to the story that "went far in undermining Kennedy's expose," according to Salon's editors. Critics of the Kennedy piece, including a devastating critique by Seth Mnookin in The Panic Virus, "further eroded any faith we had in the story," they wrote.

Kennedy's allegations spurred an 18-month investigation by a U.S. Senate committee. That report found allegations of CDC misconduct to be "unsubstantiated," and concluded that there was no cover-up.

So why does Kennedy's story still frighten parents? What really happened? Is mercury in vaccines still a concern? Why does Simpsonwood continue to vex people on all sides of the vaccine debate? 

Early Concerns About Mercury

The FDA Modernization Act of 1997 called for the FDA to assess the risk of all foods and drugs that contained mercury. In late 1998, the FDA asked vaccine manufacturers to detail the use of mercury in vaccines.

A CDC and FDA review quickly found that in the first six months of life, children were getting a cumulative dose of mercury from vaccines that exceeded the EPA's maximum safe exposure level. All of the mercury from vaccines comes from a compound called thimerosal.

To be on the safe side, vaccine makers agreed to remove thimerosal from vaccines as soon as possible. Single-dose vaccines are now thimerosal free (some may still have tiny traces of the compound), but no replacement yet has been found for thimerosal in the multi-dose vials.

Thimerosal is a mercury compound. Ironically, it has long been used to make vaccines safer. Tiny quantities of thimerosal kept vaccines free of dangerous germs that used to cause deadly infections in healthy children.

When researchers added up all the mercury in the infant vaccines, it was 40% greater than the amount of mercury the EPA considered a safe environmental exposure. This was a shock, recalls Christopher John Clements, MD, MPH, who then was an official with the World Health Organization's immunization program.

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