July 1999 — The American Academy of Pediatrics and the Public Health Service issue a joint statement explaining the decision to minimize children’s exposure to ethylmercury. The vaguely worded statement, meant to calm, only increases parents’ fears. It says, in part, "current levels of thimerosal will not hurt children, but reducing those levels will make safe vaccines even safer."
2001 — By the end of 2001, only one vaccine commonly administered to children — the influenza shot — contains thimerosal.
2003 — The CDC releases a study of more than 120,000 children that showed no relationship between thimerosal and autism. Officials there receive threats.
2004 — A panel at the Institute of Medicine, the nation’s leading independent advisor on science and health policy, unanimously determines that a review of more than 200 epidemiological and biological studies has revealed no evidence of a causal relationship between either thimerosal or MMR and autism.
June 2005 — Rolling Stone magazine publishes a piece by Robert F. Kennedy, Jr., called "Deadly Immunity" that accuses the government of protecting drug companies from litigation by concealing evidence that mercury in vaccines may have caused autism in thousands of kids. The piece will later be roundly discredited for, among other things, overestimating the amount of mercury in childhood vaccines by ninetyfold; Rolling Stone issues a series of corrections and clarifications that do little to unring the bell.