Robert F. Kennedy Jr. said Tuesday that he will head up a panel on vaccine safety for Donald Trump.

The president-elect’s transition team spokeswoman later walked that back, saying that he is “exploring the possibility” of forming a panel on autism, but “no decisions have been made.”

Let’s hope Trump drops any idea of a vaccine panel headed by Kennedy. For more than a decade, Kennedy has promoted anti-vaccine propaganda completely unconnected to reality. If Kennedy’s panel leads to even a small decline in vaccine rates across the country, it will result in the waste of untold amounts of money and, in all likelihood, the preventable deaths of infants too young to be vaccinated.

That wasted money will largely affect public health departments, whose budgets are already strained. A 2010 study in Pediatrics calculated the public sector expenses of containing a measles outbreak in which 11 children were infected at $124,517, an average of more than $10,000 per infection. That’s not to say that families won’t be affected as well: During that outbreak, 48 children too young to be vaccinated had to be quarantined at an average cost of $775 per family; medical costs for one infant who was infected were close to $15,000.

But those costs pale into comparison to the loss that will be felt by families who lose children to vaccine-preventable diseases, which typically strike when children are infected while still too young to be vaccinated.

Take pertussis, more commonly known as whooping cough. There have been several dramatic spikes in pertussis infections in the past decade, and in 2012 there were 48,277 reported cases in the US—the most since 1955. More than 87 percent of all of the country’s pertussis deaths from 2000 to 2014 were in infants younger than 3 months, which meant they were too young to have gotten their first pertussis shot.

Kennedy made his name in the anti-vaccine movement in 2005, when he published a story alleging a massive conspiracy regarding thimerosal, a mercury-based preservative that had been removed from all childhood vaccines except for some variations of the flu vaccine in 2001. In his piece, Kennedy completely ignored an Institute of Medicine immunization safety review on thimerosal published the previous year; he’s also ignored the nine studies funded or conducted by the Centers for Disease Control and Prevention that have taken place since 2003.

I first wrote about Kennedy and his foray into the anti-vaccine movement in “The Panic Virus,” my book about the persistence of the myth that vaccines can cause autism. Below is a lightly edited version of my chapter on Kennedy, titled “A Conspiracy of Dunces.”

While Kennedy has been brazen in publicizing outright lies, he appears to be less loquacious when faced with skeptical reporters. I attempted to contact Kennedy more than 20 times over an 18-month period. At various points, I was told that he was considering my interview request, that he was on vacation, that he was dealing with a family crisis, that he wasn’t feeling well, that he was behind in his emails, and that he was on the verge of calling me back. (He never did.)