Robert F. Kennedy Jr. is being accused of undermining vaccine science and destabilizing American health care. At a U.S. Senate hearing last week, he faced sharp criticism from both parties. Nine former leaders of the Centers for Disease Control are calling for urgent action, warning his influence threatens the health of every American. Former CDC director Dr. Mandy Cohen explains why, and Alberta infectious disease specialist Dr. Lynora Saxinger describes how Kennedy’s message is eroding