As measles outbreaks popped up across the U.S. this winter, pediatricians waited for the nation's public health agency to send a routine, but important, letter that outlines how they could help stop the spread of the illness.

One in 31 8-year-olds had autism in U.S. communities examined by the Centers for Disease Control and Prevention, a small increase from previous years, according to a report released Tuesday. The study comes as autism is attracting intense interest from President Donald Trump and Secretary of Health and Human Services Robert F.

Public health experts say the anti-vaccine views fronted by the HHS secretary are wrong and undermine trust in science. But a recent three-day gathering shows his followers still believe in him.