In August, Health and Human Services Secretary Robert F. Kennedy Jr. told then-CDC director Susan Monarez that changes would be coming to the childhood vaccination schedule in September, according to Monarez's testimony on Capitol Hill on Wednesday.

Her comments allege Kennedy had already decided to make changes to the childhood vaccine schedule prior to an analysis of data by the CDC's independent advisers.

Monarez also said she had a conversation with Kennedy on August 25 in which Kennedy said President Donald Trump had been briefed on those plans.

"In that morning meeting, he did say that he had spoken to the president. He spoke to the president every day about changing the childhood vaccine schedule," Monarez testified.

The CDC's advisory committee on vaccines, called ACIP, will meet later this week and consider different vaccines that are recommended for children.

According to Monarez, Kennedy asked her to promise to sign off on any forthcoming updates to vaccine recommendations without giving specifics about what those plans would be.

"He did not have any data or science to point to," Monarez said. "As a matter of fact, we got into an exchange where I had suggested that I would be open to changing childhood vaccine schedules if the evidence or science were supportive, and he responded that there was no science or evidence associated with the childhood vaccine schedule. And he elaborated that CDC had never collected the science or data to make it available related to the safety and efficacy."

"To be clear, he said there was not science or data, but that he still expected you to change the schedule?" Republican Sen. Bill Cassidy, the chairman of the Senate Committee on Health, Education, Labor and Pensions, asked Monarez.

"Correct," she said.

ABC News has reached out to HHS for comment on Monarez's testimony.

Kennedy is a longtime vaccine skeptic who has promoted false information about the harms of vaccines. With Kennedy at the helm of HHS, major medical organizations have expressed extreme alarm about restrictions to COVID-19 vaccines that have already taken place and warned of potential further restrictions to routine childhood vaccines.

Monarez says she was ousted because she held the line and refused to endorse vaccine policies not supported by scientific evidence.

Routine childhood vaccines have prevented more than one million premature deaths from vaccine-preventable illness, according to a CDC analysis of 117 million children born between 1994 to 2023.

According to Monarez, Kennedy also asked her to meet with Aaron Siri, a lawyer who previously worked for Kennedy and has pushed the FDA to revoke approval of the polio vaccine.

Monarez testified she was concerned that more children would die of vaccine preventable illnesses.

"I believe preventable diseases will return, and I believe that we will have our children harmed for things that we know they do not need to be harmed by polio, measles, diphtheria, 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. I worry about the future of trust in public health."

RFK Jr. said 'changes' coming to the childhood vaccine schedule in September, according to Monarez