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 17 members of the CDC's vaccine advisory committee, who were ousted last week, argued their abrupt dismissal has "left the U.S. vaccine program critically weakened."

Fiona Havers, who oversees CDC respiratory virus data, told colleagues she no longer had confidence the data would be used objectively to set vaccine policy.