Kennedy last week announced he would "retire" the entire panel that guides U.S. vaccine policy. He also quietly removed Dr. Melinda Wharton — the veteran Centers for Disease Control and Prevention official who coordinated the committee's meetings.

The Advisory Committee on Immunization Practices helps the agency make recommendations on who should get certain vaccines.

U.S. Health and Human Services Secretary Robert F. Kennedy Jr. said on Thursday he promised to allow U.S. Senator Bill Cassidy to pick a candidate for a key panel of vaccine advisers. Kennedy, who has a long history of questioning the safety of vaccines contrary to scientific evidence,