During his Senate confirmation hearings, Health Secretary Robert F. Kennedy Jr. suggested he wouldn’t undermine vaccines. “I am not going to go into HHS and impose my preordained opinions on anybody at HHS,” he said. “I’m going to empower the scientists at HHS to do their job and make sure that we have good science that is evidence based.”

The reconstituted C.D.C. panel will revisit the standard vaccination schedule. The former head of an anti-vaccine group is now a special federal employee.

The Trump administration’s new vaccine advisers endorsed this fall’s flu vaccines for just about every American but threw in a twist: Only use certain shots free of an ingredient antivaccine groups have falsely tied to autism.