Ousted CDC Director Susan Monarez testifies about RFK Jr., vaccines

At the close of the hearing, Cassidy spoke about the CDC's guidance that infants should receive a dose of the hepatitis B vaccine at birth and the possibility that ACIP will vote to change the recommendations for that vaccine, among others.

Cassidy detailed his expertise on the topic and said he has seen people die from the infection. For children who are infected with hepatitis B, more than 90% develop chronic, lifelong infection, he said.

The senator noted that mothers are not mandated to give their newborns the hepatitis B vaccine, but instead ensures the shot is covered by insurance if the mother decides to do so. He said that since the birth dose of the hepatitis B vaccine was approved, infections in newborns dropped by 68%.

"That is an accomplishment to make America healthy again, and we should stand up and salute the people that made that decision because there's people who would otherwise be dead if those mothers were not given that option to have their child vaccinated," Cassidy said.

The senator warned that if ACIP changes its recommendation regarding the birth dose of the hepatitis B vaccine, insurance companies no longer have to pay for it and parents will be forced to pay out-of-pocket.

After being asked by Democratic Sen. Angela Alsobrooks of Maryland if Houry believes Kennedy is "incompetent and dangerous to the American people's health," Houry said she thinks "he should resign."

She added that she believes in optimism and was hopeful as he came into office.

"I was prepared to welcome him," Houry said. "After seeing his Senate Finance testimony, and the number of misstatements, seeing what he has asked our scientists to do and to compromise our integrity, and the children that have died under his watch, I think he should resign."

Cassidy later announced that Mullin left the committee room and told reporters he was mistaken in claiming that Monarez's conversation with Kennedy was recorded.

Still, the chairman reiterated, "if there is a recording, it should be released and it would beg the question of what other conversations were recorded."

In response to Sen. Andy Kim, a Democrat from New Jersey, about what would have happened if Monarez fired career officials as Kennedy requested, she claimed the secretary told her the plan was to fire leadership and promote their deputies until compliance was achieved.

"If the deputies did not do what I had wanted, I needed to fire them, promote the next group, and continue to do so until I got to an organization that was compliant with my demands," she said.

"So, the plan was to literally just kind of keep firing until there was somebody in that position that was willing to go along with what Secretary Kennedy was asking?" Kim asked.

"That is what he communicated to me, yes," she said.

Following up on Mullin's line of questioning to Monarez and his assertion that Kennedy's discussions with her were recorded, Cassidy said the committee has a right to have access to the materials.

"If HHS has a recording, I ask them to release the recording," the chairman said. "I'd also like to know why it was recorded, but releasing the recording would be radical transparency, and this is about fulfilling the president's vision of radical transparency. This is allegiance to President Trump's values."

Cassidy asked for the recording to be released, but said if one doesn't exist, Mullin should retract his line of questions. He also added that the committee requested documents or communications from Health and Human Services that would "bring transparency" to the situation surrounding Monarez's firing and said the committee has not received them.

"I'm also curious as to why only one senator was given this and why we're just hearing about it now, and why didn't the secretary share it at the Senate Finance Committee hearing?" Cassidy asked.

Sanders raised similar concerns.

"How does that happen, if it is true, that one senator has access to an alleged tape recording of a meeting?" he said. "This is what we're dealing with right now. This is a very politicized situation, and it's unfortunate."

In response to a question from Sen. Ed Markey, a Democrat from Massachusetts, Houry said if the ACIP votes to change the hepatitis B vaccine recommendation from birth to age 4, it "would not be based on data."

Houry added she hopes this hearing makes the ACIP reconsider such a change.

"I would want them to keep (the vaccine) at birth," Houry explained. "I think there's a lot of moms that don't know they have hepatitis that can then transmit it to their baby, and even if the mom is hepatitis B negative, we don't know what the home situation is."

Mullin claimed that Monarez's conversation with Kennedy, during which they discussed her trustworthiness, was recorded and said other unnamed people in the room for the exchange refute her retelling.

"You can testify one way or you can prove that you're lying or be honest with this committee," the Oklahoma Republican said. "I'm giving you the opportunity to be honest here because you've been really walking around the edges and not being truthful."

Mullin refuted that the conversation matched Monarez's recollection.

"All we're looking for is you to be honest and you haven't been," the senator claimed. "You're not being honest about the conversation you're having, you're not being honest with the timeline and you won't even give the answers of who your attorneys were."

Sen. Markwayne Mullin, a Republican from Oklahoma, accused Monarez of having an "an honesty issue," pressing her on details of her firing.

"I believe I received an email from the White House indicating that my services were no longer needed," Monarez said.

"What time was that?" he asked.

"Sometime in the afternoon, sometime in the evening," she said.

"So you got all the attorneys late at night?" Mullin asked. "You got all the attorneys after business hours to retain them?"

"I don't recall," she said.

"I think you do," he said.

"I don't recall this specific time or day that I retained them," she said.

"I still think you have an honesty issue, because it wasn't that long ago. And I think I could recall when I hired an attorney," he said.

During an exchange with Sen. Lisa Murkowski, an Alaska Republican, about continuity in expertise at the CDC, Houry said she believes openness to change and supporting an administration's priorities are important within the top ranks of the agency.

Houry said she was selected to serve as the transition lead for the CDC before the start of the second Trump administration and said she was the last career official in the Office of the Director.

"Are you saying that everyone that is remaining is a political [appointee]? And so there is … there must be somebody that is providing that career science then?" Murkowski said.

Houry said that at the next level down, there are center directors, but said 80% of those officials are serving in an acting capacity because of retirements, firings or resignations.

Murkowski then questioned Monarez about whether she was directed to not speak to career officials at the CDC.

"I was directed to only work with the political appointees that he had put in place at CDC and not to speak or work with the career scientists," Monarez said.

She later said that she was also instructed not to speak with senators.

Republican Sen. Ashley Moody of Florida repeatedly pressed Monarez to introduce the lawyers who accompanied her to the hearing and demanded she produce their names for the record.

The Florida senator claimed the attorneys are "anti-Trump" and suggested without evidence that Monarez has a "whole network of people who are trying to embarass the president or go after the president."

"My attorneys have been publicly associated with me," the former CDC official said, adding that she sought their counsel either on the day or shortly after she was fired.

Moody asked Monarez whether she coordinated a "public spectacle" surrounding her firing.

"I was terminated abruptly," Monarez said.

Houry said the lawyers are Abbe Lowell and Mark Zaid, who are representing numerous former officials suing the Trump administration over their firings. Zaid has a long history of representing whistleblowers, while Lowell's former clients include Jared Kushner and Ivanka Trump, the president's son-in-law and daughter, as well as Hunter Biden, former President Joe Biden's son.

Moody also went after Monarez for calling Cassidy about her concerns regarding Kennedy's demands of her and questioned whether she had an "advance plan" to spur a public hearing.

Monarez said she had made commitments to senators during her confirmation hearing to work with Congress, which prompted her outreach to the committee.

Cassidy, the chairman, said that Monarez's decision to contact him or any other committee member was "entirely appropriate" given that the Senate HELP Committee conducts oversight of the CDC and approved her nomination to lead the agency.

Cassidy said he reached out to Kennedy and the White House to express concerns about what Monarez alleged.

"As soon as the director was fired, the HELP Committee began reviewing the situation, as it is our responsibility, and any and all communications with the witnesses was conducted by HELP staff in coordination with attorneys," he said.

Sanders said it is "rather astounding that anyone is concerned that government heads of agencies talk to the elected officials of the United States of America. That is what they are supposed to do."

Sen. Tim Kaine, a Democrat from Virginia, told Monarez he had no concern about her qualifications during her confirmation hearing but said he voted against her, citing worries about the direction of HHS.

"(It) made me question you very significantly, on your backbone, a trait that is not in long supply in this town," he said. "And I was wrong. I apologize to you for being wrong. I think it's important when you're wrong to admit you're wrong."

Kaine later asked about measles outbreaks in his state and the issues with funding cuts, to which Houry agreed with his concerns.

"80% of funding of CDC goes out to state and local communities. So as we see budget cuts to CDC, your community will see that too, and the boots on the ground work that you did in Virginia is the gut is exactly the heart of public health," she said.

In a response to Hickenlooper about what keeps the former officials up at night, Monarez said "the next outbreak."

"I don't believe that we'll be prepared," she said.

Houry said she's concerned about the future of CDC and public health in the U.S.

"Given what I have seen that we continue down this path, we are not prepared — not just for pandemics, but for preventing chronic health disease, and we're going to see kids dying of vaccine preventable diseases," she said.

Monarez said the ACIP deliberations are "critically important" and "impact real lives."

"The more that we can do to ensure that we are achieving radical transparency, accountability, and evidence-based decision making, I would highly encourage it," she said in response to a question from Hickenlooper.

In response to a question from Democratic Sen. John Hickenlooper of Colorado about access to the COVID-19 vaccine, Houry said her mother lives in Virginia and "she was unable to get it."

During Kennedy's testimony before the Finance Committee earlier this month, the secretary told senators that "anybody can get the booster" but said it is "not recommended for healthy people." Kennedy testified that "most Americans will be able to get it from their pharmacy for free."

CVS and Walgreens, major pharmacy chains, announced last month they were requiring a prescription for the COVID-19 vaccines or not offering it at all in some states because of the regulatory environment.

Sen. Chris Murphy, Democrat from Connecticut, asked about fears following the deadly shooting that took place at the CDC's Atlanta headquarters earlier this year.

"Clearly, you have to be unhinged to take a gun and fire it into a medical building, but these conspiracy theories about vaccines and about the people who are recommending vaccines I fear, they come with consequences," Murphy said. "Do you fear for the safety of the CDC, and of medical personnel, if these beliefs about the CDC actually recommending things that hurt people continue to become mainstream?"

Monarez said she fears continued misleading information "will undermine, not just the safety and health of our children, but it will also exacerbate some of these tensions."

Houry said she knows people that won't speak about vaccines now and have removed their names off of papers because they don't wish to present publicly anymore.

"They feel they were personally targeted because of misinformation," Houry said.

"So you know personnel who now will not put their name behind good science that they know would protect the health and safety of families and children because of their fear of violence?" Murphy clarified.

"Correct," she said.

Sen. Tommy Tuberville, a Republican from Alabama, pressed Monarez about Kennedy's claim that she said she is "untrustworthy," and that is one of the reasons she was removed from her position as CDC director.

"He told me he could not trust me. He told me he could not trust me because I had shared information related to our conversation beyond his staff," Monarez recalled of the exchange. "I told him, if you cannot trust me, then you can fire me."

Monarez also denied declining to update the CDC website to remove phrases like "birthing people," and "health equity" in line with Mr. Trump's executive order.

"I did not refuse to do that," she said.

Monarez detailed Kennedy's verbal attacks on the CDC and its employees, which she said were "particularly pointed and particularly hurtful and disparaging."

She said Kennedy called the CDC "the most corrupt federal agency in the world" and called its employees "horrible people." Kennedy also allegedly said CDC workers were killing children and were "bought by the pharmaceutical industry," according to Monarez.

The former CDC chief also recalled that Kennedy said the CDC forced people to wear masks and social distance during the COVID pandemic "like a dictatorship."

"And the one I think that hurt me the most was a particularly vivid phrase, he said, during the COVID outbreak, CDC told hospitals to turn away sick COVID patients until they had blue lips before allowing them to get treatment," Monarez said.

Asked about the accuracy of Kennedy's remarks, Monarez said, "those statements are not true."

Monarez said the secretary was very upset with her when she refused to comply with his directives and likened his demeanor to his appearance before the Senate Finance Committee earlier this month.

Sen. Maggie Hassan, a Democrat from New Hampshire, admitted that during Monarez's confirmation process, she was "frankly unsure about whether you would stand up to Secretary Kennedy," but today, she thanked her for doing just that.

Hassan also asked how Kennedy reacted when Monarez pushed back on his demands about future vaccine decisions.

"He was very upset," Monarez said of Kennedy. "The entire meeting was very tense. He was very upset throughout the entirety of our discussion. And it was not a productive exchange of information."

During an exchange with Sen. Roger Marshall, a Republican from Kansas, Monarez stressed that she would "stand behind scientific integrity with every decision I ever make."

"If I am put in a position of having to say I will cede the scientific integrity to retain my job, then I am not the right person for the position," she said.

Monarez continued: "I believe that we must have science and evidence to support the best decisions for our children and others who will benefit from vaccines."

Sen. Susan Collins, a Republican from Maine, asked Monarez what the implications are for public health if major CDC decisions are made by political staff instead of career scientists.

"It really concerns me," Monarez replied. "These are very important, highly technical discussions that have lifesaving implications for our children and others who need vaccines."

If decisions are not based on the best available data and evidence, she said, "it does put at risk our children, it puts at risk others who need these vaccines, and it takes us into a very dangerous place in public health."

Sen. Tammy Baldwdin, a Democrat from Wisconsin, asked Monarez whether Kennedy had given her instructions on how to interact with members of Congress.

Monarez said that after the morning meeting with Kennedy during which he asked her to make pre-commitments about ACIP recommendations, she became "very concerned" and "alarmed" that she was not being consistent with the pledges she had made to Congress about transparency and integrity.

Monarez said she reached out to the Senate HELP Committee to share her concerns, and said when Kennedy learned of that outreached, he "was very concerned that I had spoken to members of Congress, and he told me I was never to do it again."

In answering a question from Sen. Susan Collins, a Maine Republican, Houry said the response to the measles outbreak earlier this year by Kennedy's HHS differed in several ways to previous infectious disease outbreaks she's been part of.

First, she never briefed Kennedy, which would normally happen during an outbreak response, Houry said.

"The second thing is, he said things like vaccines had fetal parts, and I had to send a note to our leadership team to correct that misinformation," she added.

Houry added they were also asked to include certain medications in their toolkits for physicians, but said, "I couldn't allow that as there wasn't evidence for that and would result in harm."

Sen. Patty Murray, a Democrat from Washington, asked Houry to discuss how she learned of the CDC's new guidance about the COVID-19 vaccine, and Houry reiterated that she learned of it through social media.

"It is unthinkable to me that the chief medical officer at CDC was left in the dark about such a consequential public health decision that affected real people," Murray said.

Asked whether the change was supported by scientific evidence, Houry said scientists at the CDC haven't yet seen the data. She told Murray that she asked for a written memo from HHS because "I couldn't implement guidance off of a tweet."

Houry said that while CDC officials asked for data to back up the changed guidance for the COVID vaccine, "we have not received the data to date."

Turning to the childhood vaccination schedule for measles, chicken pox and hepatitis B, Monarez said she is not aware of any scientific evidence to support changing the age for receiving those shots.

"I was certainly open if there were scientific data sets or evidence associated with anything that would help keep our children safe. I was open to seeing it. I have not seen that data directly," Monarez said.

Houry said she had asked for the data and modeling to support those decisions as to the childhood vaccine data, but has not seen it.

When asked about whether she would feel confident in telling Americans to trust the newly appointed ACIP members, Monarez said she's "very nervous about it."

"I don't know, they haven't met yet," she added. "I know that the medical community has raised concerns about whether or not, again, they have the commensurate backgrounds to be able to understand the data, the evidence, and to evaluate it appropriately, but I certainly will be watching."

Houry agreed, adding she has "significant concerns, as the public hasn't been able to weigh in."

GOP Sen. Rand Paul of Kentucky asked Monarez specific questions about the COVID vaccine, including if it prevents transmission.

"The COVID vaccine can reduce viral load in individuals who are —" Monarez started.

"Does it prevent transmission? Paul interjected.

"When you have reduced viral load, you will have reduced transmission," Monarez said.

"But in other words, it doesn't prevent transmission.You can still transmit the virus if you've had the vaccine," Paul replied.

Paul eventually turned to fears over vaccine risks in younger people, accusing Monarez of refusing to fire those who believe the COVID vaccine should be given at six months.

"That's what this is about. You didn't resist firing the beautiful, the perfect, beautiful scientists that are career people and unobjective and unbiased. You wouldn't fire the people who are saying that we have to vaccinate our kids at six months of age, that's who you refuse to fire," he said.

Monarez said that she had not discussed vaccinations of children of that age with the scientists Kennedy wanted her to fire.

Monarez said that she met with Kennedy at least twice before she was fired, first at her swearing-in and the second time in August, when he toured the CDC buildings hit in the shooting.

Monarez said that during a conversation with Kennedy on Aug. 25, the secretary asked her to commit to firing CDC scientists, and to signing off on ACIP recommendations regardless of whether there was scientific evidence to support those recommendations.

Monarez said that when she refused to resign and agree to those conditions, Kennedy informed her that he had already spoken to the White House about having her removed.

As to the childhood vaccine schedule, Monarez said Kennedy informed her it would be changed beginning in September and "I needed to be on board with it." Kennedy said he had spoken to Mr. Trump about changing the childhood vaccine schedule, she added.

Monarez said she told the secretary that she would be open to changing the childhood vaccine schedule if there was scientific evidence or science to support doing so. But "he responded that there was no science or evidence associated with the childhood vaccine schedule," she said.

Monarez said Kennedy also asked her to meet with Aaron Siri, a lawyer who has petitioned the federal government to revoke its approval of the polio vaccine.

In response to questions from Sanders, Monarez said she refused to rubber stamp vaccine recommendations without seeing the evidence behind them because she "built a career on scientific integrity."

"My worst fear was that I would then be in a position of approving something that would reduce access to lifesaving vaccines to children and others who need them," she said.

She added she believes preventable diseases will return and children will be harmed by things they "do not need to be harmed by," including polio, measles, diphtheria and whooping cough.

"I worry about the ramifications for those children in illness, and in death. I worry about our school systems, I worry about our medical institutions having to take care of sick kids that could have been prevented by effective and safe vaccines," she said.

After Houry's opening statements, Cassidy said they did not swear in the witnesses because it "would have required consent of the minority, and the minority did not agree to that."

Sanders added, to the best of his knowledge, no person has ever been sworn in before the HELP Committee, including Kennedy, who appeared before the committee on two occasions and was not sworn in.

"To change the rules right now, in a highly politicized moment, seems to me to be extremely unfair to Dr. Monarez and Dr. Houry," Sanders said. "We can discuss that with future hearings… but not right now."

Houry, who resigned after Monarez was removed, said that she made the decision to leave her post because "CDC leaders were reduced to rubber stamps, supporting policies not based on science and putting American lives at risk."

She criticized Kennedy's leadership as head of Health and Human Services and accused him of censoring CDC science, politicizing its processes and stripping the agency's leaders of independence.

"I could not in good conscience remain under those conditions," Houry said.

She said the nation is on track to see significant increases in preventable diseases and declines in health "due to the secretary's actions."

"Trust and transparency have been broken," Houry said. "Here again, the problem is not too much science, but too little."

Houry detailed the flow of information within the Department of Health and Human Services under Kennedy's tenure, including learning that Kennedy had changed the CDC's COVID-19 vaccine guidance through a social media post. She said CDC scientists have not seen the data or justification for those changes.

Houry also said the secretary's office ordered the removal of a scientific document on thimerosal, an organic compound used as a preservative in drug products, from the CDC's website and allowed an "unvetted presentation" on the additive before ACIP.

"That kind of last-minute alteration undermines confidence and the deliberations that follow, and is certainly not radical transparency," Houry said.

Monarez continued in her opening statement that she agrees with President Trump that "we should not hesitate to ask for proof about our vaccines."

"I also agree with his most recent comments that vaccines are not controversial because they work," she added. "Demanding evidence is exactly what I was doing when I insisted CDC recommendations be based on credible science."

She said she was "never misaligned with the administration priorities" or goals of Kennedy.

"I remain supportive of those priorities. The question is whether they can be achieved without the expertise required at CDC regarding trustworthiness, I cannot define that word for Secretary Kennedy," she added.

Vaccine policy must be guided by credible data, not predetermined outcomes, she added, a view she previously shared in a September op-ed in The Wall Street Journal.

In her opening statement, Monarez began by describing the promises she made before the Senate committee during her confirmation hearing and the praise she received from Mr. Trump and Kennedy. Still, she noted that her tenure as CDC director was short.

Monarez immediately refuted the public reasons given by the Trump administration for her firing, including Kennedy's claim that she said she was "untrustworthy."

"None of those reflect what actually happened," Monarez said. She added, "Today should not be about me. Today should be about the future of trust in public health."

Monarez walked through the timeline of events leading up, including the early August shooting outside the CDC's headquarters

The former CDC director said that Kennedy demanded her do "two things that were inconsistent with my oath of office and the ethics required of a public official": He directed her to commit in advance to approving every ACIP recommendation regardless of the scientific evidence, and directed her to dismiss without cause career officials responsible for vaccine policy, Monarez said.

Monarez said she could not approve recommendations from ACIP without reviewing evidence and had no basis to fire the scientific experts at the CDC.

"I was fired for holding the line on scientific integrity, but that line does not disappear with me," she said.

A month after Kennedy supported Monarez's confirmation, he called her a "liar" and "untrustworthy," Sen. Bernie Sanders said in his opening statement.

"Really? How did Monarez go from being a public health expert with unimpeachable scientific credentials who had the full confidence of Secretary Kennedy into being a liar and untrustworthy in less than a month — that is quite a transformation," Sanders said.

He said he thinks the answer is "fairly obvious," saying Monarez was fired because she "refused to act as a rubber stamp."

"Secretary Kennedy's dangerous agenda to substantially limit the use of safe and effective vaccines that would endanger the lives of the American people, and people throughout the world," he said, adding it is unacceptable that we have a HHS secretary who does not believe in established science, including in views of vaccines.

"It is absurd to have to say this in the year 2025 but vaccines are safe and effective," Sanders said. "Of course, it is not just my view, far more importantly, it is the overwhelming consensus of the medical and scientific communities."

Chairman Bill Cassidy, a Republican from Louisiana, opened the hearing shortly after 10 a.m. said the proceedings are a "direct response to President Trump's call for radical transparency in how we conduct government affairs."

Cassidy, a physician, said he has the "absolute obligation" to do the best he can to serve Americans and ensure they can rely on clear guidance from the CDC.

"Children, and I would say adults', health is at risk," he said.

Cassidy questioned why Monarez was removed from her position less than a month after she won Senate confirmation and said the hearing is the first step for answering why members of CDC leadership resigned before they could be fired. He warned against turmoil in the upper ranks of the CDC and said it is harmful for the American people.

"What happened? Did we fail? Was there something we should've done different?" Cassidy asked.

He said the hearing is not about politics but rebuilding the nation's trust in the nation's public health institutions.

In a statement to CBS News, HHS spokesperson Andrew Nixon said Monarez's prepared remarks for the Senate HELP committee have "factual inaccuracies and leave out important details," adding she "acted maliciously to undermine the President's agenda and was fired as a result."

"Some of her biggest offenses include neglecting to implement President Trump's executive orders, making policy decisions without the knowledge or consent of Secretary Kennedy or the White House, limiting badge access for Trump's political appointees, and removing a Secretarial appointee without consulting anyone," the statement continued. "When she refused to acknowledge her insubordination, President Trump fired her."

Dr. Debra Houry was one of three senior officials at the CDC who resigned last month citing growing political interference in the agency's scientific work, particularly regarding vaccines.

Houry, who was he CDC's chief science and medical officer, stepped down hours after the White House announced Monarez's firing.

In her prepared remarks for the Senate HELP committee meeting Wednesday, Houry says 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."

The "final tipping point," Houry added, came when Monarez was blocked from trying to strengthen "transparency and scientific rigor at CDC."

"At that moment it was clear CDC's leaders would no longer be able to defend their staff or their science. That is why Drs. Daskalakis, Jernigan, and I resigned together," her remarks continued.

Monarez, who was ousted from her job as CDC director less than a month after her Senate confirmation, plans to say that she believes she was fired because she would not agree to pre-approve the recommendations from a newly reconstituted vaccine advisory panel known as the Advisory Committee on Immunization Practices, or ACIP. She also plans to say she refused to fire career scientists at the agency, according to a copy of her opening remarks that were obtained by CBS News.

"Secretary Kennedy demanded two things of me that were inconsistent with my oath of office and the ethics required of a public official," Monarez plans to say in her opening remarks. "He directed me to commit in advance to approving every ACIP recommendation regardless of the scientific evidence. He also directed me to dismiss career officials responsible for vaccine policy, without cause. He said if I was unwilling to do both, I should resign."

Monarez will testify that she told Kennedy she couldn't "preapprove recommendations without reviewing the evidence" and "had no basis to fire scientific experts."

At a Senate hearing earlier this month, Kennedy shared his recollection of telling Monarez "she had to resign because I asked her, 'are you a trustworthy person?' and she said no."

Read more here.

Monarez was nominated for the CDC role in March by President Trump, who called her "an incredible mother and dedicated public servant" who "understands the importance of protecting our children, our communities, and our future."

She had already been serving as the acting head of the CDC since January, and previously worked as the head of the Advanced Research Projects Agency for Health.

Unlike most recent CDC directors, she holds a Ph.D. but is not a medical doctor.

During her confirmation hearing before the Senate Health committee in July, she received praise from the Republican chairman and physician Sen. Bill Cassidy, while Democrats on the committee grilled her about a range of health topics, from vaccines to fluoride and her assertion that she would be an "independent thinker" while working for Kennedy.

In her prepared remarks, obtained by CBS News, Monarez is expected to warn that if Kennedy's vaccine advisory panel proceeds with a meeting scheduled for later this week, there's a "real risk" vaccines for children could be limited.

Kennedy replaced all the members of the Advisory Committee on Immunization Practices, or ACIP, with a new group that includes some outspoken vaccine critics.