With a brief memo, Florida Surgeon General Joseph Ladapo has subverted a public health standard that's long kept measles outbreaks under control.

On Feb. 20, as measles spread through Manatee Bay Elementary in South Florida, Ladapo sent parents a letter granting them permission to send unvaccinated children to school amid the outbreak.

The Department of Health "is deferring to parents or guardians to make decisions about school attendance," wrote Ladapo, who was appointed to head the agency by Florida Gov. Ron DeSantis, whose name is listed above Ladapo's in the letterhead.

Ladapo's move contradicts advice from the Centers for Disease Control and Prevention.

"This is not a parental rights issue," said Scott Rivkees, Florida's former surgeon general who is now a professor at Brown University. "It's about protecting fellow classmates, teachers, and members of the community against measles, which is a very serious and very transmissible illness."