Updated September 17, 2025 at 1:13 PM CDT
In a much anticipated public appearance Wednesday, Susan Monarez, the former head of the Centers for Disease Control and Prevention, defended her short tenure at the embattled public health agency.
She testified that she was ousted last month because she refused to cede to Health Secretary Robert F. Kennedy Jr.'s demands to pre-approve vaccine recommendations for the public and fire career scientists.
"He just wanted blanket approval," Monarez told members of the Senate Committee on Health, Education, Labor and Pensions on Wednesday. "Even under pressure, I could not replace evidence with ideology."
Over the three-hour hearing, Monarez repeatedly countered Kennedy's claims – which he outlined in a Wall Street Journal op-ed and reiterated during a congressional hearing in early September – that she was fired because she was not a "trustworthy person."
Monarez described a string of events that she said eventually led to her dismissal, culminating with a "tense" meeting in late August when she clashed with Kennedy over his plans for an influential CDC committee that issues recommendations on vaccines.
According to her testimony, Kennedy told Monarez at the time that the "childhood vaccine schedule would be changing starting in September" and that she "needed to be on board."
"He was very upset," Monarez said. "He called CDC the most corrupt federal agency in the world, emphasized that CDC employees were horrible people. He said that CDC employees were killing children and they don't care."
Kennedy told her he had "already spoken with the White House several times about having" her removed, she said.
In his opening statement, Sen. Bill Cassidy, a Republican from Louisiana who chairs the committee and was key to Kennedy's confirmation, pointed out that she had received broad support from his party during her confirmation. Monarez was the first CDC director ever confirmed by the Senate.
When she was sworn in, Kennedy himself stated that she had "unimpeachable scientific credentials."
"What happened? Did we fail? Was there something we should have done differently?" said Cassidy, who is also a medical doctor. "The American people need all the facts, not a version of the facts that fits a certain narrative or agenda."
Also testifying was the CDC's former chief medical officer, Dr. Deb Houry, who resigned alongside other top agency officials at the end of last month in protest of changes at CDC.
Houry said she resigned "because Secretary Kennedy's actions repeatedly censored CDC science, politicized our processes, and stripped agency leaders of the ability to protect the health of the American people." She added that she felt CDC leaders "were expected to serve as rubber stamps for the secretary's decisions."
In response to several questions from senators, Monarez recounted her memory of a conversation with Kennedy that precipitated her firing, saying Kennedy told her he couldn't trust her. "I told him, if he could not trust me, he could fire me," she testified.
In his own Senate testimony earlier this month, Kennedy said: "I told her she had to resign because I asked her, 'Are you a trustworthy person?' And she said, 'No.'"
The hearing was marked by some heated exchanges between Monarez and Republicans on the committee who took aim at her decision to hire attorneys who have represented clients that have sued President Trump and tried to poke holes in her recounting of events.
"All we're looking for is you to be honest, and you haven't been," Sen. Markwayne Mullin, R-Okla. fired at Monarez, claiming that her conversation with Kennedy had been recorded – only to later tell reporters that he'd been mistaken.
Cassidy demanded that if such a recording does turn out to exist, that it be entered into the record, and called for "radical transparency" on this issue.
A few Republicans seemed troubled by what Monarez revealed in her testimony.
"This is not about you. It's about trust in our public institutions," Sen. Lisa Murkowski, R-Alaska, said, "What happens to this scientific mission when there are no career public health professionals that are in these positions to advise on the policy and to protect the scientific integrity?"
How Democrats received Monarez' testimony Wednesday stood in sharp contrast to her confirmation hearing when they opposed her nomination.
"I owe you an apology," said Sen. Tim Kaine, D-Va., "I had concern about your backbone and I was wrong."
The hearing comes on the eve of the next meeting of the vaccine advisory committee, which is scheduled for Thursday morning in Atlanta. The panel is expected to re-evaluate the vaccine schedule for hepatitis B and the MMRV vaccine for children, and on the COVID-19 vaccine.
In June, Kennedy fired the entire 17-member Advisory Panel on Immunization Practices, chose several new members at the time and selected five more on Monday. Many of the members he chose have a history of being critical of vaccines.
During her testimony, Monarez said Kennedy asked her to meet with Aaron Siri, a trial attorney who specializes in vaccine lawsuits and who has worked closely with Kennedy. Siri has called for the Food and Drug Administration to revoke approval for the polio vaccine.
The hearing was just the latest reminder of the ongoing turbulence at the CDC where Kennedy has replaced many career scientists in leadership positions with political appointees, pushed debunked claims related to the safety of vaccines and scrapped long-standing processes for crafting vaccine policy.
The possible outcome of Thursday's vaccine advisory meeting was on the mind of many who spoke at the hearing. In his closing statement, Sen. Cassidy offered a strong defense of the current hepatitis B vaccine recommendations for infants.
"There are people who would otherwise be dead if those parents weren't given the option to have their child vaccinated," he said.
Department of Health and Human Services spokesperson Andrew Nixon said via e-mail: "On the childhood vaccination schedule, the upcoming ACIP meeting will decide the outcome. Any potential changes to the childhood vaccine schedule will be based on the latest available science and only after the ACIP recommends it and the Acting CDC Director reviews and approves those recommendations."
He added: "Susan Monarez was tasked with restoring the CDC to its core mission after decades of bureaucratic inertia, politicized science, and mission creep eroded its purpose and squandered public trust—and she refused to do it."
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