At a sometimes testy Senate committee hearing on Wednesday, Dr. Susan Monarez, the former head of the Centers for Disease Control and Prevention, repeatedly said that Health Secretary Robert F. Kennedy Jr. had abandoned science in dismantling longstanding vaccine policy and demanding adherence to his views.
The testimony before the Senate health committee by Dr. Monarez, who was fired in late August after less than a month in the role, detailed the fraught state of vaccine policy under Mr. Kennedy. It also offered a preview of the next two days, when an influential C.D.C. vaccine panel will meet.
As part of its review, the panel will discuss several important immunizations, among them the Covid and hepatitis B shots and the M.M.R.V. shot for measles, mumps, rubella and varicella (chickenpox), and could potentially upend longstanding advice on the vaccines.
At the hearing on Wednesday, Democratic senators hammered away at their opposition to Mr. Kennedy, and asked Dr. Monarez for details on what she described as pressure by Mr. Kennedy to rubber-stamp his policies.
She told senators that the hearing should amplify concerns about “the future of trust in public health.” Dr. Debra Houry, who resigned from her post as the chief medical officer of the C.D.C., testified that Mr. Kennedy repeatedly ignored or did not consult scientific evidence of the value of vaccines. She said he should resign.
Andrew Nixon, a spokesman for Health and Human Services, said in an email that Dr. Monarez was fired “for declaring herself untrustworthy to the Secretary and acting maliciously to undermine the President’s agenda.”
Some committee Republicans used the hearing to voice repeated criticisms of the C.D.C.’s pandemic-era guidance on vaccines and other measures, arguing that the agency’s policies helped to foster vaccine hesitancy and distrust of the science.
Here are five takeaways.
Kennedy plans to change the childhood vaccine schedule.
The C.D.C.’s current immunization recommendations protect children from 16 diseases. According to Dr. Monarez, Mr. Kennedy said that he spoke with President Trump “every day” about changing that regimen.
Mr. Kennedy has long condemned the recommended slate of childhood vaccines. In particular, he has called into question the hepatitis B shot that newborns receive. Several senators raised questions about the recommendation during the hearing.
Senator Bill Cassidy, Republican of Louisiana, the chairman of the health committee and himself a liver specialist, closed the hearing by speaking passionately about how rates of the disease fell in the decades after the C.D.C. recommended the shot for newborns. “That is an accomplishment to Make America Healthy Again,” he said, parroting Mr. Kennedy’s slogan.
Mr. Kennedy criticized a number of immunizations during his years as an anti-vaccine activist. He has also falsely claimed that the polio vaccine might have caused a wave of cancers “that killed many, many, many, many, many more people than polio ever did.”
In June, Mr. Kennedy fired all 17 members of a critical vaccine panel, the Advisory Committee on Immunization Practices, or ACIP. He handpicked their replacements.
“I’m very nervous about it,” Dr. Monarez said of the panel’s upcoming sessions this week and its decisions.
After the hearing, Mr. Cassidy told reporters that Americans should not have confidence in changes to the childhood vaccine schedule that come from the committee.
Mr. Nixon, the spokesman for the department of Health and Human Services, said that “any potential changes to the childhood vaccine schedule will be based on the latest available science,” and that changes would be made only after the advisory committee recommended them and the acting director of the C.D.C. approved them.
Dr. Monarez recounted the run-up to her firing.
Dr. Monarez provided more details about the events that led to her firing. She told senators that she met with Mr. Kennedy three times on Aug. 25. In those meetings, she testified that Mr. Kennedy asked her to fire vaccine scientists without cause.
She said he also asked her to pledge that she would approve in advance the forthcoming recommendations of the C.D.C.’s influential vaccine committee without having seen them. “He just wanted blanket approval,” Dr. Monarez said.
Mr. Kennedy, she said, told her she should resign if she refused his order. Dr. Monarez said she then reached out to lawmakers, including Mr. Cassidy. Later, Mr. Kennedy learned that she had contacted senators, she said, and told her that he did not trust her.
“I told him that if he could not trust me, he could fire me,” Dr. Monarez said.
Senator Markwayne Mullin, Republican of Oklahoma, accused Dr. Monarez of “not being truthful” about her description of that meeting, and warned her that it had been recorded. He later told reporters that he was mistaken about the recording.
Dr. Monarez said Mr. Kennedy was “very animated” and “very upset” during their meetings, and that he made a number of false statements about the C.D.C., including that its “employees were killing children and they don’t care.”
Kennedy unveiled policy changes online.
Mr. Kennedy has repeatedly called for “radical transparency” for the nation’s public health institutions. But Dr. Monarez and Dr. Houry said they were sometimes kept in the dark about policy changes.
Dr. Houry revealed that she had learned of changes to Covid vaccine policies through a post on X, the social media website. In a 58-second video, Mr. Kennedy and other H.H.S. officials announced in May that the C.D.C. was no longer recommending that healthy children and pregnant women get the vaccine.
Scientists at the C.D.C. still have not seen any scientific evidence to justify those changes, she said.
The health secretary’s office also ordered that a document outlining evidence the vaccine preservative thimerosal does not cause autism be removed from the agency’s website, Dr. Houry said.
Dr. Monarez fears for the future of Americans’ health.
Drs. Monarez and Houry expressed concern that if faith in vaccine science were undermined, it would cause a resurgence of vaccine-preventable diseases in the United States.
“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,” Dr. Monarez said. As trust in public health institutions crumble, the doctors said, the country becomes less able to tackle future pandemics, or to address current outbreaks.
“There is certainly still work to be done to improve the health of our nation,” Dr. Houry said. “But when we erode the institutions and processes that deliver evidence-based interventions to detect, prevent and respond to health challenges, as Secretary Kennedy is doing, we trade proven gains for avoidable harm.”
Republicans blamed the C.D.C. for a loss of trust.
Several committee Republicans used the hearing to revisit the C.D.C.’s pandemic policies, condemning the agency’s past embrace of masks, social distancing, early school closings and Covid vaccines for children.
“I think the C.D.C. is the cause of vaccine hesitancy, that you are the problem,” said Senator Roger Marshall, Republican of Kansas. Mr. Kennedy has long espoused similar arguments, and the Department of Health and Human Services posted a clip of the senator’s remarks on its official X account.
Dr. Monarez pointed out to the senators that the C.D.C. does not mandate vaccines and instead makes recommendations. She repeatedly called for parents to make decisions in consultation with their pediatricians.