FILE PHOTO: The exterior of the Center for Disease Control and Prevention (CDC) main campus in Atlanta, Georgia, U.S., August 27, 2025. REUTERS/Alyssa Pointer/File Photo

By Leah Douglas, Dan Levine and Julie Steenhuysen

WASHINGTON (Reuters) -Departing senior officials of the U.S. Centers for Disease Control and Prevention left the agency due to changes to its vaccine advisory board and other vaccine policies, they told Reuters in an interview on Thursday.

Deb Houry, Demetre Daskalakis and Dan Jernigan, who resigned on Wednesday in a major leadership upheaval at the nation's top public health agency, said that vaccine advisers appointed by Secretary of Health and Human Services Robert F. Kennedy Jr., a longtime critic of vaccines, were making recommendations before reviewing data.

"We became aware by conversations with work groups that many of them were deciding on what recommendations would be before actually having the data. And for us, that's problematic," Houry said in a group interview from the Emory University School of Public Health shortly after the three were escorted from the agency's Atlanta headquarters.

"As scientists, you should never know in advance what you want the data to show," added Houry, who had been the CDC's chief medical officer.

Kennedy has made sweeping changes to the nation's vaccine policies, including firing all members of the CDC's expert vaccine advisory panel, the Advisory Committee on Immunization Practices, in June. He replaced them with hand-picked advisers including several like-minded anti-vaccine activists.

The HHS department did not immediately respond to a request for comment.

Houry said that once confirmed, CDC Director Susan Monarez tried to change the ACIP, including by adding a new designated federal official and having relevant documents posted for public comment, but was blocked in her effort.

"She wanted to have engagement and transparency. Those things were not done," Houry said. "She was given feedback from HHS that those couldn't happen, and she was called to a meeting with the secretary on Monday. For us, we knew that if our scientific leader couldn't make changes like that, we could no longer stay."

Monarez abruptly departed the agency on Wednesday. The White House said later that she was fired, though her attorneys say her firing is illegal. Monarez did not respond to request for comment.

Daskalakis directed the National Center for Immunization and Respiratory Diseases, while Jernigan led the National Center for Emerging and Zoonotic Infectious Diseases.

The three officials had previously decided that if they left the agency, they would do so together, they said. They gathered items from their offices and met with staff before being escorted out on Thursday, they said.

(Reporting by Dan Levine in San Francisco, Julie Steenhuysen in Chicago and Leah Douglas in Washington; Editing by Chizu Nomiyama and Bill Berkrot)