Anti-Vaccine Advocate Gives Misleading Presentation to CDC Advisory Committee
When the Centers for Disease Control and Prevention’s vaccine advisory panel met on June 26, it heard a 20-minute presentation from retired nurse practitioner and anti-vaccine advocate Lyn Redwood about the risks of thimerosal, a long-used preservative in vaccines that in the U.S. is only used in multidose seasonal influenza shots.
The committee -- newly installed by Health and Human Services Secretary Robert F. Kennedy Jr. -- was set to vote on whether it should recommend that people only use flu vaccines without thimerosal, which contains a type of mercury.
Normally, presentations before the committee are made by CDC experts, who present evidence on an issue using a rigorous framework that considers not only the benefits and harms, but also the practical implications of any decision.
Not so here. Redwood’s presentation played up the potential harms of thimerosal, but failed to include evidence demonstrating the compound’s safety.
“Removing a known neurotoxin from being injected into our most vulnerable populations is a good place to start with Making America Healthy Again,” Redwood said at the end, reading from her slides.
“There were many studies on the other side of the question that documented the safety of thimerosal that were not included, so it was a highly opinionated, data-sparse, incomplete presentation,” Dr. William Schaffner, a professor of infectious diseases at the Vanderbilt University Medical Center, told us, speaking of Redwood’s presentation. “And certainly in recent years, it would not have been permitted in that form.”
As Science Editor Jessica McDonald and Staff Writer Kate Yandell detail in a new story, while concerns were raised in the late 1990s about the preservative, including the notion that it might cause autism, numerous studies have shown that it has no harmful effects in the small doses found in vaccines, other than rare allergic reactions or mild side effects.
The type of mercury in thimerosal is ethylmercury, which is substantially different and less toxic than methylmercury, which is what accumulates in fish. The amount of mercury in a flu shot is about the same as what is in a 3 ounce portion of tuna, according to the Food and Drug Administration.
The committee ultimately voted to recommend only single-dose flu shots, which are thimerosal-free, for all people.
The direct impact of the vote is likely to be small in the U.S., since only 4% of flu shots administered last season were multidose and contained thimerosal. But experts told Jessica and Kate the change might still reduce access for some people, as the single-dose versions are more expensive. And without evidence of harm, the decision could also fuel vaccine hesitancy.
For more, read the full story: "Presentation Before CDC Vaccine Panel Misleads About Thimerosal."
|
