"The overwhelming evidence from several well-designed studies indicates that childhood vaccines are not associated with autism," the chairman of the IOM panel, Harvard scientist Marie McCormick, told reporters last May 18.
The panel went further: It took the unusual step of urging that research money go instead to more "promising" areas. You can't slam a door much harder than that.
But 12 months later, that door seems slightly ajar. One big doorstop is the new 441-page book by David Kirby called "Evidence of Harm," a compelling portrayal of parents and scientists who have pushed the vaccines-autism theory. They contend that a mercury-based preservative called thimerosal, in an increasing number of vaccinations, triggered an autism epidemic in the 1990s.
Thimerosal was phased out of U.S. childhood vaccines beginning in 1999.
One memorable vignette in Kirby's book is a meeting between several of those advocates and Dr. Julie Gerberding, who had been director of the Centers for Disease Control and Prevention less than two years.
Last May 12, a week before the IOM report, Gerberding flew in from Atlanta to meet them -- at her request -- in the Rayburn House Office Building on Capitol Hill. Rep. Dave Weldon, R-Fla., a medical doctor who is a persistent critic of thimerosal and the CDC's handling of the issue, also was present.
Taking turns, the parents and scientists methodically laid out their case.
Mady Hornig of Columbia University described how mice with an autoimmune genetic predisposition develop autistic-like behaviors after being injected with thimerosal-containing vaccines.
"Hornig played the videos for Gerberding, who suddenly appeared stunned," Kirby recounts in his book. "She brought her hands to her face in disbelief.
"Dave Weldon had a similar reaction. He stopped Hornig in the middle of her ghastly presentation. 'Wait a minute,' he said. 'Am I to understand you correctly? You injected these mice with the same amount of mercury, relatively speaking, that infants receive in vaccines, and you saw these kinds of mutilatory behaviors? You saw this mouse eat through the cranium of his cellmate?'
"'Yes,' she replied calmly."
The Institute of Medicine saw the same presentation before issuing its report but rejected it as unconvincing.
Gerberding was polite but noncommital, Kirby writes. As she left, she said, "I am not afraid of controversy, and I am determined to follow the science."
Call it coincidence, but it's striking how much less dismissive of thimerosal concerns the CDC is these days, compared with the Institute of Medicine and others.
The National Network for Immunization Information, for instance, launched a pre-emptive broadside against "Evidence of Harm." That group represents the mainstream medical establishment, including the American Academy of Pediatrics, the American Nurses Association and the American Academy of Family Physicians. Their members, it should be noted, were among those who administered the vaccines in question on the recommendation of the CDC.
"Warning: Controversial vaccine book," the NNII statement was headlined. "Reporter David Kirby has recently written a book ... purporting that there is a link between thimerosal and autism and other developmental disorders."
That's a bit of an overstatement, considering the first two sentences of Kirby's book: "Does mercury in vaccines cause autism in children? Anyone hoping to find proof that it does in the pages that follow is advised to put this book down now."
The NNII asserted that "extensive evidence shows no link between vaccines and neurodevelopmental disorders, including autism. This evidence is based on well-established scientific studies.
"Continued attempts to link vaccines and autism run the risk of diverting attention away from efforts to understand the cause or causes of autism," the group said.
The CDC also issued a release on Kirby's book. Its thrust was different -- that the book is a "look back" to a time when thimerosal was in childhood vaccines.
"Given the historical nature of the book, it is important to emphasize that today, with the exception of some flu vaccines, none of the vaccines used in the U.S. to protect preschool children against 12 infectious diseases contain thimerosal as a preservative.
"As the IOM concluded in a recent report, the vast majority of studies, which have involved hundreds of thousands of children in a number of countries, have failed to find any association between exposure to thimerosal in vaccines and autism; that is, they have failed to find any evidence of harm," the CDC said.
It's worth noting the contrasts in the statement. The doctors and nurses group says "extensive evidence shows no link." Dr. McCormick at the Institute of Medicine says "overwhelming evidence" shows no link.
But the CDC, which unlike such groups has ongoing access to the actual data, merely states that studies so far "have failed to find any association."
"CDC continues to support research related to autism," the statement said, "including studies designed to examine the possible causal association between autism and other possible environmental causes, including thimerosal-containing vaccines. ... Research in these areas is ongoing."
Ongoing research that includes thimerosal as a possible cause of autism? Supported by the CDC?
Put simply, the CDC isn't ruling out anything -- contrary to the Institute of Medicine's declaration that more research on thimerosal is a waste of money, contrary to the medical establishment's pronouncement that continuing to look could cause harm.
Consider Gerberding's comments April 28, 2004, at a House subcommittee hearing: "We don't have the evidence to show that the thimerosal preservative is a risk, but you know we have an open mind about that."
Apparently the Institute of Medicine's findings three weeks later didn't completely reassure her, because this February -- almost a year after the IOM report -- she said the same thing in an interview with NBC.
"Right now, the scientific evidence doesn't provide any framework for concluding that thimerosal or immunizations in any way affect autism," she said. "But we have to have an open mind about that."
An open mind, not a closed door. Ongoing research, not ending research. That's quite a difference. Experts who are certain thimerosal didn't cause the autism epidemic may want to have a word with Dr. Gerberding.
Next: Mercury, the Amish and the autism epidemic.