On Sunday, Robert F. Kennedy Jr. met with the families of two girls who had died from measles in West Texas—and raised doubts about the safety of vaccines. “He said, ‘You don’t know what’s in the vaccine anymore,’” Peter Hildebrand, whose 8-year-old daughter Daisy’s funeral had been held just hours earlier, told me. “I actually asked him about it.”

RFK Jr., an anti-vaccine advocate who President Donald Trump tapped to be secretary of Health and Human Services.