Kennedy’s Top Health Aide to Lead CDC After Director Fired (2)

Aug. 29, 2025, 2:24 AM UTC

The Trump administration is tapping a deputy of Health and Human Services Secretary Robert F. Kennedy Jr. as the acting director of the Centers for Disease Control and Prevention, after moving to oust the agency’s current head in a clash over vaccine policy.

Jim O’Neill, the Health and Human Services deputy secretary, will be the CDC’s acting director, according to an all-staff email sent by Kennedy to CDC employees Thursday night.

“I want you to hear directly from me - this mission remains strong, and so does my full confidence in you,” Kennedy wrote in the message viewed by Bloomberg News. “Reform does not diminish your work; it strengthens it.” O’Neill and HHS did not immediately respond to inquiries.

The move follows the firing of Susan Monarez just weeks into her tenure as the agency’s director. The contested dismissal occurred after a confrontation with Kennedy, when Monarez pushed back on his vaccine stance. Attorneys representing her said she was “targeted” because she “refused to rubber-stamp unscientific, reckless directives and fire dedicated health experts.”

The clash, plus the resignation of three other senior CDC leaders, has deepened the turmoil at the agency. Kennedy, a longtime vaccine critic who has promoted unorthodox public health views, has moved to overhaul the nation’s immunization policies.

In his message to staff, Kennedy said he and President Donald Trump were on the same page, writing, “President Trump and I are aligned on the commonsense vision for the CDC: Strengthen the public health infrastructure by returning to its core mission of protecting Americans from communicable diseases by investing in innovation to prevent, detect and respond to future threats.” He said Americans were “ready to believe in this agency again” and that “together, we will restore trust.”

In an interview with Fox News Thursday morning, the health secretary said the CDC wasn’t sufficiently aligned with Trump’s agenda and needed to be overhauled, slamming policies it advocated during the Covid-19 pandemic.

Monarez’s firing came the same week that Trump moved to put his stamp on other institutions, seeking to fire Federal Reserve Governor Lisa Cook and Robert Primus, a Democrat from a federal agency weighing in on a major rail merger. It also came as the agency continues to recover from a shooting when a gunman frustrated about the Covid vaccine fired nearly 200 bullets into the campus.

O’Neill previously worked at HHS from 2002 to 2008, then became managing director at Clarium Capital, a global macro investment fund, and was CEO of the Thiel Foundation. It’s unclear how closely O’Neill will conform to Kennedy’s efforts to remake immunization policy in the US, including the reconstitution of a key CDC panel that helps determine how vaccines are used in the country.

In a Senate hearing earlier this year, O’Neill said he’s “very much in favor of vaccines,” adding that “they’re one of the greatest public health interventions in human history.”

(Updates with Kennedy email starting in the second paragraph.)

To contact the reporters on this story:
Jennifer A. Dlouhy in Washington at jdlouhy1@bloomberg.net;
Rachel Cohrs Zhang in Washington at rzhang698@bloomberg.net;
Jessica Nix in New York at jnix20@bloomberg.net;
Josh Eidelson in San Francisco at jeidelson@bloomberg.net

To contact the editors responsible for this story:
Justin Sink at jsink1@bloomberg.net

Laura Davison, Karthikeyan Sundaram

© 2025 Bloomberg L.P. All rights reserved. Used with permission.

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