The Centers for Disease Control and Prevention (CDC), America’s top public health agency, has been thrown into turmoil in recent days following the abrupt ouster of its director, Susan Monarez, and the resignation of several of its most senior officials. The shakeup, which unfolded in late August 2025, has sparked rare bipartisan alarm in Washington and ignited a fierce debate over the future of the nation’s vaccine policies and the integrity of its public health leadership.
According to AP and Newsweek, the White House announced on August 28 that Monarez would be replaced by Jim O’Neill, the deputy secretary at the Department of Health and Human Services (HHS). O’Neill, a former investment executive without a medical background, is expected to serve as acting CDC director, though it remains unclear if he will retain both roles. The decision to remove Monarez came less than a month after she was sworn in, making her the shortest-serving CDC director since the agency’s founding in 1946.
The move was part of a broader effort by Health Secretary Robert F. Kennedy Jr.—a longtime figure in the anti-vaccine movement—to reshape federal vaccine policy. Kennedy has advanced a series of controversial changes, including removing members of the CDC’s key vaccine advisory panel and ending funding for some mRNA vaccines. Under new CDC guidelines, effective by August 31, 2025, COVID-19 vaccines are now authorized only for people 65 and older, or for younger individuals with at least one health condition putting them at high risk for severe outcomes. Healthy people under 65 may now face significant hurdles in accessing COVID shots, a shift that has drawn concern from public health experts.
“Vaccines are available for all patients who choose them after consulting with their doctors,” Kennedy stated in a social media post, attempting to reassure the public. But critics say the new rules could leave millions unprotected and undermine decades of progress in disease prevention. The White House justified Monarez’s removal by saying she was “not aligned with the president’s agenda,” while her lawyers countered that she had refused “to rubber-stamp unscientific, reckless directives and fire dedicated health experts.” Monarez is now challenging her dismissal, arguing that only President Trump, who nominated her in March, has the authority to fire her.
The fallout from Monarez’s ouster was immediate and dramatic. Within hours, four senior CDC officials resigned in protest, including Dr. Debra Houry (deputy director and chief medical officer), Dr. Demetre Daskalakis (head of the National Center for Immunization and Respiratory Diseases), and Dr. Daniel Jernigan (director of the National Center for Emerging and Zoonotic Infectious Diseases). Staff gathered on the Atlanta campus to bid farewell, with bouquets, cheers, and chants of “USA not RFK,” as reported by AP.
In separate interviews after their resignations, both Houry and Daskalakis voiced deep concerns about the direction of the agency under Kennedy. Daskalakis, speaking on ABC’s “This Week,” warned, “I only see harm coming. Based on what I’ve heard with the new members of the Advisory Committee for Immunization Practices, or ACIP, they’re really moving in an ideologic direction where they want to see the undoing of vaccination. They do want to see the undoing of mRNA vaccination.” He also pushed back against the new vaccine guidance, noting that many young children hospitalized with COVID had no underlying conditions and should still qualify for vaccines.
Houry, in an interview with CNN’s “Inside Politics,” said Kennedy had not worked with CDC scientists before issuing the new guidance. “None of our scientists have ever briefed the secretary on vaccines,” she said. She further explained that she learned about the policy changes through Kennedy’s social media post, not through official channels. “We have a vaccine committee that’s scheduled in a few weeks, and that was one of the reasons why I resigned. That committee is going to be staffed by people who don’t have expertise in vaccine science and other types of scientific methodologies.”
This committee, the Advisory Committee on Immunization Practices (ACIP), has become a flashpoint. Kennedy dismissed the entire panel in June, accusing members of being too closely aligned with manufacturers, and replaced them with several vaccine skeptics. The revamped ACIP is scheduled to meet on September 18 to vote on recommendations for standard childhood shots, including those for hepatitis B and a combination vaccine for measles, mumps, rubella, and chickenpox. The legitimacy of this meeting is now in question.
Republican Senator Bill Cassidy of Louisiana, chair of the Senate Committee on Health, Education, Labor, and Pensions, issued a warning after Monarez’s firing and the resignations. “These high profile departures will require oversight by the HELP Committee,” Cassidy wrote on X, as reported by Newsweek. He called for the ACIP meeting to be postponed, citing “serious allegations… about the meeting agenda, membership, and lack of scientific process.” Cassidy, a physician, said that if the meeting proceeds, any recommendations should be “rejected as lacking legitimacy given the seriousness of the allegations and the current turmoil in CDC leadership.”
Democratic voices have also been sharply critical. Senator Jon Ossoff of Georgia posted, “Tonight’s events are yet more evidence that putting a quack like Bobby Kennedy in charge of public health was a grave error. The Trump Administration has been engaged for months in a campaign to destroy the CDC, America’s preeminent disease-fighting agency. The Administration’s extremism and incompetence are putting lives at risk.”
Even those who initially supported Monarez’s nomination, like Cassidy, have expressed alarm at the rapid erosion of scientific standards at the agency. Cassidy noted in June that some of Kennedy’s new ACIP appointees “do not have significant experience studying microbiology, epidemiology, or immunology.” Former CDC acting director Dr. Richard Besser told AP that Monarez had resisted orders to fire her team and refused to automatically approve recommendations from Kennedy’s handpicked vaccine advisers, calling her “one of the last lines of defense against this administration’s dangerous agenda.”
The strife at the CDC comes amid a broader climate of unrest. Earlier in August, a police officer was killed in a shooting at the agency’s headquarters, an act reportedly motivated by anger over COVID-19 vaccines. The attack underscored the heightened tensions and misinformation swirling around public health policy in the United States.
As the dust settles, questions remain about the future of the CDC and the nation’s approach to immunization. Monarez’s attorney, Mark Zaid, maintains that she “has neither resigned nor received notification from the White House that she was fired,” and insists she remains the legitimate CDC director. The White House, for its part, is standing by its decision, stating, “Susan Monarez is no longer director of the Centers for Disease Control and Prevention. We thank her for her dedicated service to the American people. Secretary Kennedy has full confidence in his team at the CDC, who will continue to be vigilant in protecting Americans against infectious diseases at home and abroad.”
With Kennedy warning of more turnover at the CDC and a pivotal ACIP meeting looming, the agency faces an uncertain path. The stakes are high—not just for the institution, but for the millions of Americans who rely on its guidance to keep their families safe from infectious disease.
