2000 Simpsonwood CDC conference
The 2000 Simpsonwood CDC conference (officially titled Scientific Review of Vaccine Safety Datalink Information) was a meeting convened in June 2000 by the Vaccine Safety Datalink examining the possibility of a link between the mercury containing compound called thimerosol in vaccines and neurological problems in children who had received those vaccines.
A 2005 article by Robert F. Kennedy, Jr., published by Rolling Stone and Salon.com, focused on the Simpsonwood meeting as part of a conspiracy to withhold or falsify vaccine-safety information. However, Kennedy's article contained numerous major factual errors and, after a number of corrections, was ultimately retracted by Salon.com. Nonetheless, on the basis of Kennedy's claims, the conference gained notoriety in the anti-vaccination movement, where it formed the basis of various conspiracy theories and allegations.
In 1997, the Congress of the United States passed a resolution requiring the Food and Drug Administration (FDA) to review the thiomersal content of approved drugs and biologics. The Simpsonwood conference was held to perform this review. At the conference, representatives from the CDC, the FDA, and the pharmaceutical industry held two days of discussion, focusing on adverse event data derived from the Vaccine Safety Datalink. Three vaccines of primary interest were discussed: hepatitis B vaccine, DPT vaccine, and the Hib vaccine.
The attendees included experts in the fields of rapporteur, and a statistician. The meeting also served as a prelude to vaccine policy meetings held by the Advisory Committee on Immunization Practices (ACIP), which sets U.S. vaccine policy for the CDC. The session was also to serve as the initial meeting of the ACIP work group on thimerosal and immunization.
Presentations and supporting documents from the conference were subject to a news embargo until June 21, 2000, at which point they were published by the ACIP. After the conference, researchers carried out a planned second phase to further analyze and clarify the study's preliminary findings. The results of this second analysis were published in 2003.
In the anti-vaccination movement
The June 20, 2005 issue of Rolling Stone contained an article written by Robert F. Kennedy, Jr. entitled "Deadly Immunity". The article, which was also published on Salon.com, focused on the Simpsonwood conference and alleged that government and private industry had colluded to "thwart the Freedom of Information Act" and "withhold" vaccine-safety findings from the public. Kennedy claimed that the Simpsonwood data linked thiomersal in vaccines to the rise in autism, but that the lead researcher later "reworked his data to bury the link between thimerosal and autism." However, Kennedy's article contained numerous significant errors of fact. The article overstated the amount of ethylmercury in vaccines by several orders of magnitude, erroneously claimed that a researcher held a patent on one of the discussed vaccines, and erroneously claimed that the rotavirus vaccine contained thiomersal, among other errors.
Although Salon.com later admitted that these errors "went far in undermining Kennedy’s exposé", at the time they chose not to retract the piece in the interest of transparency. Instead, the magazine corrected Kennedy's article five times due factual errors, ultimately retracting it in January 2011 because the editors felt that criticisms of the article and clear flaws in the science connecting autism and vaccines undermined the value of the article.
By the time the final study results discussed at Simpsonwood were published in 2003, the lead researcher, Thomas Verstraeten, had gone to work for GlaxoSmithKline. Kennedy contended that the delay in publication gave Verstraeten sufficient time to fix the data around the CDC's alleged objective of obscuring a link between thimerosal and autism. Verstraeten denied the allegations, and published an account of the matter in the journal Pediatrics.
In September 2007, the U.S. Senate Committee on Health, Education, Labor and Pensions rejected allegations of impropriety against Verstraeten and the CDC. Addressing the conspiracy alleged by Kennedy and members of the anti-vaccination movement, the Committee found that: "Instead of hiding the [Simpsonwood] data or restricting access to it, CDC distributed it, often to individuals who had never seen it before, and solicited outside opinion regarding how to interpret it. The transcript of these discussions was made available to the public."
- Offit 2008: pp. 94–95
- Lauerman, Kerry (January 1, 2011). "Correcting our record".
- Offit 2008: p. 91
- Transcript: pp. 3–10
- Transcript: p. 11
- Transcript: pp. 256–257
- Verstraeten T (April 2004). "Thimerosal, the Centers for Disease Control and Prevention, and GlaxoSmithKline". Pediatrics 113 (4): 932.
- "Salon: Corrections 2005".
- "Scientific Review of Vaccine Safety Datalink Information June 7–8, 2000 (transcript); Thimerosal VSD study Phase I, 2000" (PDF). Retrieved April 8, 2010. Hosted by SafeMinds,