At an event late last week in Arizona, anti-vaccine activist and Donald Trump transition team member Robert F. Kennedy Jr. said he’d fire and replace 600 people from the National Institutes of Health on “day one” of a second Trump term. The NIH is one of the public health agencies Kennedy loathes the most—and despite still lacking any defined role in a new administration, he’s clearly relishing the opportunity to promise retribution against them. In comments that were first...