Today, President-elect Donald Trump met with a backer of the false idea that vaccines may be behind the rise in autism diagnoses. The result seems to be a worst-case scenario: Robert F. Kennedy, Jr. has accepted a position within the Trump administration, where he will chair a group evaluating vaccine safety and scientific integrity.

Update: The Trump transition team is now telling CNN that, contrary to Kennedy's claims, no decision has been made about his appointment.

Trump has a history, on Twitter and in debates, of questioning the well-established science behind the US' vaccination program. He has insinuated that vaccines cause autism and has suggested that the current vaccination schedule is overly aggressive. There is absolutely no evidence for either of those positions. Numerous studies have debunked any connection between either vaccination or any specific components of vaccines and diagnoses of autism. And the vaccine schedule is based on a combination of medical risks and exposure probabilities; changing it would alter infants' risks.

It wasn't clear whether Trump's positions would lead to any policy decisions. But a worrying sign came when Trump met with Andrew Wakefield this fall. Wakefield helped establish fears of a vaccine-autism connection by publishing a paper, now retracted, that suggested a connection between the two. He has since had his medical license pulled due to misconduct during the preparation of that paper.

In terms of a loose grip on evidence, Trump and Wakefield have a kindred spirit in Kennedy. Kennedy has promoted the idea that a mercury-containing preservative used in vaccines causes autism. Even though the removal of the preservative from vaccines has not altered autism diagnosis rates, Kennedy has continued to argue that vaccines are unsafe.

After their meeting today, Kennedy told reporters that Trump had asked him to “chair a commission on vaccination safety and scientific integrity.” The obvious concern is that Kennedy's inability to assess scientific evidence will lead to recommendations that run counter to the best available evidence. The mention of "scientific integrity" also suggests that the commission will get into other accusations leveled by the anti-vaccine movement, namely that pharmaceutical companies have unduly influenced the research into vaccine safety.