The ousted Centers for Disease Control director, Susan Monarez, appeared before the Senate Health Committee Wednesday, saying that an enraged Secretary Robert F. Kennedy Jr. accused CDC employees of “killing children” after she refused his request to “pre-commit” to suggested changes to the childhood vaccine schedule.

Dr. Monarez testified that in an August 25 meeting, Mr. Kennedy told her he spoke with President Trump “every day” about altering the vaccine schedule. 

Mr. Kennedy insisted she do two things that she believed went against her oath of office: approve every recommendation made by his handpicked Advisory Committee on Immunization Practices, “regardless of scientific evidence,” and to dismiss career officials opposed to his vaccine policy “without cause.”

“He just wanted blanket approval, and if I could not commit to approval of each and every one of the recommendations that would be forthcoming, I needed to resign,” Dr. Monarez testified. She was fired by Mr. Kennedy, who would later call her “untrustworthy,” on August 27. 

The hearing came on the eve of ACIP’s September meeting at Atlanta, where the panel is expected to vote on Covid-19 vaccine guidance and a proposal to delay the hepatitis B vaccine birth dose until age 4.

The committee chairman, Bill Cassidy, a Republican of Louisiana, introduced Wednesday’s hearing as a direct response to the Trump administration’s call for “radical transparency.” 

Despite voting in favor of Mr. Kennedy during his Senate confirmation in February, Mr. Cassidy has been largely frustrated by the health secretary’s decision to remove Dr. Monarez from office and for his wholesale dismissal of the previous ACIP board, which he replaced with noted vaccine skeptics.

This week, Mr. Kennedy announced the addition of five new ACIP members, including a Case Western professor, Catherine Stein, who, like the ACIP chairman, Martin Kuldorff, was a vocal opponent of Covid-19 mandates. 

“If doctors do not have clear guidance or have a reason to distrust what’s coming out of the CDC, they cannot make informed decisions to protect their patients,” Mr. Cassidy said. 

Republicans on the committee spent most of the hearing attacking Dr. Monarez’s honesty and her decision to hire a “leading opponent of President Trump,” Mark Zaid, as her attorney. 

Senator Rand Paul, a Republican of Kentucky, grilled Dr. Monarez on CDC support to “blithely” follow childhood hepatitis B and Covid-19 vaccine mandates. “The burden is upon you and the people you wouldn’t fire to prove to us that we need to give our six-month-old a Covid vaccine,” Mr. Paul said. 

“I actually agree with you, and I was open to the science, I just would not pre-commit to approving all the ACIP recommendations without the science,” Dr. Monarez replied. 

“Untrue,” Mr. Paul fired back.

During the hearing, a former CDC chief medical officer,  Debra Houry, who resigned in protest over Dr. Monarez’s firing, testified that as the number of nationwide measles cases rose to 30-year highs, neither she nor the CDC official leading the outbreak response were asked to brief Mr. Kennedy. 

“He said things like vaccines had fetal parts, and I had to send a note to our leadership team to correct that misinformation,” Dr. Houry said. 

A microbiologist and immunologist by training, Dr. Monarez became the first CDC director since 1953 to not hold a medical degree, and the first confirmed under a new Senate requirement passed in 2023.

During her brief tenure as CDC director, a gunman “driven by vaccine distrust” fired hundreds of rounds into the agency’s Atlanta headquarters, killing a police officer before taking his own life.

At the close of Wednesday’s hearing, Mr. Cassidy, himself a physician and hepatologist, warned the ACIP panel altering the recommendation for a Hepatitis B birth dose could undo decades of medical progress. Hepatitis B can develop into a chronic condition in 90 percent of childhood cases.

“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,” Mr. Cassidy said.