On September 17, 2025, the halls of the U.S. Senate were anything but quiet as former Centers for Disease Control and Prevention (CDC) Director Susan Monarez took the stand. She painted a grim picture of turmoil, scientific censorship, and political interference at the nation’s top public health agency under Health Secretary Robert F. Kennedy Jr. The hearing, convened by the Senate Committee on Health, Education, Labor, and Pensions (HELP), was marked by sharp exchanges, emotional testimony, and a deepening divide over the future of vaccine policy and scientific independence in America.
Monarez, a microbiologist and the first Senate-confirmed CDC director, had held her post for just 29 days before being abruptly ousted last month. She told senators that her firing stemmed directly from her refusal to comply with Kennedy’s demands: to preapprove changes to the CDC’s childhood vaccine recommendations without scientific basis, and to dismiss CDC scientific leadership without cause. "I could have stayed silent, agreed to the demands, and no one would have known. What the public would have seen were scientists dismissed without cause and vaccine protections quietly eroded," Monarez testified, according to Benzinga. "I would have lost the one thing that cannot be replaced: my integrity."
Her testimony was echoed by Debra Houry, the former CDC chief medical officer, who resigned in protest soon after Monarez’s ouster. Houry, a decade-long veteran of the agency, described a climate of fear and intimidation under Kennedy’s leadership. She recounted how CDC scientists, fearing for their safety and careers, had begun removing their names from scientific papers and refraining from public presentations. "Each bullet was meant for a person," Houry said, referencing a recent tragic shooting at CDC headquarters by a man who believed he was harmed by the COVID-19 vaccine, as reported by PBS News. "I have many that won’t speak about vaccines now and remove their names off of papers. They don’t wish to present publicly anymore because they feel they were personally targeted because of misinformation."
The Senate hearing was as much about the present as it was about the future of public health. Monarez detailed Kennedy’s attempts to control messaging and policy, including instructing her not to speak with senators—a highly unusual request for a Senate-confirmed official. She also revealed that Kennedy had made deeply disparaging remarks about the CDC and its employees, calling the agency "the most corrupt federal agency in the world" and accusing its staff of "killing children" and being bought by the pharmaceutical industry. "He said CDC forced people to wear masks, social distance like a dictatorship," Monarez recounted, adding that the most hurtful comment was Kennedy’s claim that, during the COVID-19 outbreak, "CDC told hospitals to turn away sick covid patients until they had blue lips before allowing them to get treatment."
According to Reuters, Monarez testified that Kennedy demanded she be "on board" with planned changes to the childhood vaccine schedule for September 2025 and that she fire those who disagreed. Her resistance, she said, led directly to her dismissal. In a previous Senate hearing earlier in September, Kennedy denied these claims, labeling Monarez "a liar" and asserting that he fired her because she was not trustworthy. Monarez, however, insisted under oath that Kennedy’s demands were made explicitly during an August 25 meeting.
The Senate hearing was not without its political theatrics. Republican senators pressed Monarez aggressively, questioning her credibility and motives. Senator Markwayne Mullin of Oklahoma suggested that Monarez was lying about her interactions with Kennedy and implied that their conversation had been recorded. "That isn’t how that conversation went. And you know that, don’t you?" Mullin said, only to later admit he was mistaken about the existence of a recording, as relayed by Senator Bill Cassidy of Louisiana. Cassidy, a former physician, also highlighted a report that Kennedy had emailed Monarez on August 19, stating that all major CDC policy decisions needed approval from political appointees.
Other Republican senators, like Rand Paul of Kentucky, used the hearing as a platform to question vaccine safety, echoing Kennedy’s own anti-vaccine rhetoric on social media. Senator Ashley Moody of Florida questioned the presence of Monarez’s legal counsel, suggesting a hidden agenda. Meanwhile, Senator Roger Marshall of Kansas and Senator Jon Husted of Michigan took issue with the CDC’s approach to public health warnings, arguing that the agency’s messaging was unnecessarily alarming for parents.
Despite the partisan attacks, Monarez stood firm. She was joined in her defense by Senator Bernie Sanders of Vermont, who described her as "a public health expert with unimpeachable scientific credentials." Sanders argued that Monarez was fired for refusing to "rubber stamp" Kennedy’s "anti-vaccine recommendations," and warned that the administration’s actions signaled a "dangerous war on science." In his prepared remarks, Sanders stated, "It is absurd to have to say this in the year 2025, but vaccines are safe and effective."
The hearing also spotlighted the administration’s broader rollback of vaccine research. Sanders condemned Kennedy’s decision to cancel approximately $500 million in federal mRNA vaccine projects, warning that such cuts could leave the U.S. vulnerable in future outbreaks. The Department of Health and Human Services (HHS) has said it is winding down 22 mRNA projects to redirect funds to "safer, broader vaccine platforms," a move criticized by public health groups and academics. Experts from Johns Hopkins University have warned that scaling back mRNA research undermines pandemic preparedness.
Meanwhile, the CDC’s Advisory Committee on Immunization Practices (ACIP), which Kennedy fired and replaced with less qualified members in June 2025, convened on September 18 and 19 to discuss changes to vaccine recommendations, including those for hepatitis B and COVID-19. The new guidance, which restricts COVID-19 vaccines to those 65 and older or with high-risk conditions, has sparked confusion and concern among experts.
Amid the policy upheaval, the human toll has been severe. Over 2,000 CDC employees have been fired or targeted since Kennedy took the helm at HHS. The recent shooting at CDC headquarters, which left a police officer dead and traumatized staff, has only heightened fears. Houry described staff covering their children in daycare parking lots and dodging bullets as they left the building, a chilling testament to the climate of fear surrounding vaccine work in America today.
As the Senate hearing drew to a close, the stakes for public health, scientific independence, and the nation’s trust in its institutions could not have been clearer. The testimony of Monarez and Houry, coupled with the administration’s ongoing shake-up of vaccine policy, has left many wondering what comes next for the CDC—and for the health of the country it serves.
