NIH director Dr. Jay Bhattacharya to take over as acting head of CDC
Bhattacharya replaces Jim O'Neill, who stepped down last week.
Dr. Jay Bhattacharya, director of the National Institutes of Health (NIH), will take over as acting director of the Centers for Disease Control and Prevention (CDC), a White House official and sources familiar with the matter told ABC News.
Bhattacharya will continue in his current duties as NIH director until a permanent CDC director is nominated and confirmed, according to the White House official.
He replaces Jim O'Neill, who served as acting director of the CDC from late August 2025 until last week.
O'Neill will be nominated as the next head of the National Science Foundation, according to the White House official.
Bhattacharya rose to prominence during the COVID pandemic as co-author of the so-called Great Barrington Declaration.
Published in October 2020 and named after the Massachusetts town in which it was drafted, it called for COVID-19 lockdowns to be avoided and for a new plan for handling the pandemic by protecting the most vulnerable individuals but allowing most to resume normal activities, achieving herd immunity naturally.
The plan was criticized as "unethical" by Dr. Tedros Adhanom Ghebreyesus, director-general of the World Health Organization. Many others in public health voiced opposition to the idea, saying it would unnecessarily put people's lives at risk.
Bhattacharya continued to advocate against lockdowns, mask mandates and COVID-19 vaccine passports throughout the pandemic before being tapped by Health and Human Services (HHS) Secretary Robert F. Kennedy Jr. to lead the NIH.
This marks the third person named as head of the CDC since last summer.
Dr. Susan Monarez was confirmed as CDC director in July, but she held the post for less than a month. Monarez was fired by Kennedy for reportedly not rubber-stamping the health secretary's vaccine agenda or firing high-ranking CDC leaders whom he opposed.
The turmoil led to both Kennedy and Monarez appearing in front of Senate committees to address the ousting.
At a Senate hearing in September 2025, Monarez said she was fired by Trump and Kennedy for "holding the line on scientific integrity."
Kennedy, in a hearing before a different Senate panel earlier that month, disputed Monarez's version of events. He denied telling Monarez to accept vaccine recommendations without scientific evidence, and claimed she was fired in part because she told him she was untrustworthy.
After Monarez was fired, O'Neill, who served as Kennedy's HHS deputy secretary, was named as acting CDC director and signed off on the CDC decision to reduce the number of vaccines recommended for children and remove the universal recommendation for the hepatitis B vaccine at birth.
The shakeup in leadership at the nation's top public health agency comes amid widespread criticism by medical organizations and public health groups over the past year over how the CDC has handled major infectious disease outbreaks, changes to the childhood vaccine schedule and funding cuts.
The National Public Health Coalition (NPHC), an organization made up of current and former HHS employees, released a statement on Wednesday expressing "disappointment" with Kennedy and the Trump administration.
"CDC staff were not notified about the agency's new director, just as with the removal of Jim O'Neill, staff learned about their new leadership via reporting from the New York Times," the statement read.
"The fact of the matter is, Jay Bhattacharya is Acting CDC Director in name only. We know that Sec. Kennedy is pulling the strings, deciding the health priorities on a whim, and cutting out public health professionals."
The statement continued that the CDC is in turmoil and that staff morale is at an all-time low.
"Staff are losing hope that they will have a permanent CDC Director, let alone one who is qualified to lead the agency. Our coalition continues to stand with CDC staff and demands the Administration nominate a qualified director immediately," NPHC said.
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