As the agency rotates through a cast of leaders, it’s unclear when—or if—the US Centers for Disease Control and Prevention will get a permanent director under Donald Trump’s second term as president.
Following Jim O’Neill’s departure as acting CDC director last week, National Institutes of Health director Jay Bhattacharya will now lead both agencies temporarily. It’s the latest in a series of shakeups at Donald Trump’s CDC, which has lost about a quarter of its staff to mass layoffs carried out by Health and Human Services secretary Robert F. Kennedy Jr. last year.
Bhattacharya, a health economist with a medical degree who has never been a practicing physician, has been an outspoken critic of the CDC and its handling of the Covid-19 pandemic.
O’Neill was also the deputy secretary at HHS, the CDC’s parent agency, before being named director of the National Science Foundation this week. He took over the CDC in August after Susan Monarez’s short tenure at the agency. Monarez was confirmed as CDC director in July 2025 but was removed after just four weeks in the position. She testified that she was fired for refusing to blindly approve Kennedy’s changes to federal vaccine policy. During her brief time at the public health agency, the CDC’s main campus in Atlanta was attacked by a gunman who reportedly acted out of “discontent” with Covid-19 vaccines. The shooter killed a responding police officer. In the wake of Monarez’s firing, several top CDC officials resigned.
The Trump administration’s original pick to lead the CDC was former US congressman Dave Weldon, a physician and vocal skeptic of vaccines. The White House pulled his nomination when it became clear that he would not win enough votes to get Senate confirmation, even with Republican support.
Ronald Nahass, a physician and president of the Virginia-based Infectious Diseases Society of America, which represents scientists and health care professionals, says the chaos at the CDC could have devastating consequences.
“We are woefully unprepared for a bioterror attack or novel pathogen outbreak without leaders capable of directing a national response, including investigation, scaling up testing, clear public communication, and coordination with health care professionals across the country,” he says. “Critical activities have been overlooked, de-prioritized, or stopped due to political rather than scientific reasons.”
He cites delayed surveillance data on a variety of pathogens and the lack of timely, robust guidance for clinicians and the public on issues such as measles. Mass layoffs at the CDC have also meant a loss of technical and financial support to state and local health departments.
“You would never run a company with a series of temporary CEOs,” says Georges Benjamin, executive director of the American Public Health Association, who previously served as secretary of the Maryland Department of Health and Mental Hygiene.
But that may be the administration’s intention. A 2023 law change championed by Senator Ted Cruz requires the CDC director to be confirmed by the Senate, similar to other high-ranking government positions that are appointed by the president. Cruz and other Republicans pushed for the change in response to the CDC’s handling of the Covid-19 pandemic. They claimed the agency had “unchecked power” with a leader that wasn’t confirmed by the Senate.
Requiring the CDC director to be confirmed by the Senate was meant to be a check on that power. In absence of an official nominee, the administration can name temporary leaders to carry out its agenda, such as further changes to vaccine recommendations.
White House spokesperson Kush Desai tells WIRED that Bhattacharya was tapped to serve as the acting CDC director because he has the “complete confidence” of President Trump. “His academic credentials, research experience, and proven track record of restoring Gold Standard Science–based decisionmaking at the NIH make him eminently qualified to run the CDC until a permanent director is nominated and confirmed,” Desai said, adding that he had no information on who the nominee would be. Desai did not respond to a follow-up question on the timeline for a new nominee.
“Trump has a history of avoiding the Senate confirmation process when it's likely to be difficult—most famously with his US Attorney appointments—so it's not a stretch to think he's doing the same at CDC, given the damage the administration's health policies have caused and the growing opposition to his assault on public health,” says Bruce Mirken, a spokesperson for Defend Public Health, a grassroots network of public health researchers, health care workers, and allies that was formed in late 2024 after Kennedy’s nomination.
Under the Federal Vacancies Reform Act, a Senate-confirmed official can take on a second, or even a third, job in an acting capacity. Since being sworn in as secretary of state last year, Marco Rubio has also served in acting roles for the US Agency for International Development and the National Archives and Records Administration.
There are time limits to acting service, however. If there is no nominee, there is only a 210-day period where someone can use the acting CDC administrator title. In this case, the clock started after Monarez’s departure, says Anne Joseph O'Connell, a professor at Stanford Law School.
That 210-day limit is up on March 25, at which point Bhattacharya could still keep the CDC running day-to-day—managing operations, issuing routine guidance, and coordinating responses—because those are “delegable” tasks. But certain functions of the job, by law, can be carried out only by the CDC director or official acting director. Performing those duties after the 210-day period could be subject to legal challenge.
At some point, O'Connell says, having one confirmed official serving as the acting leader of multiple agencies undermines the spirit of the Federal Vacancies Reform Act. “We should worry about the harms to governance,” she says. “It is hard to do two full-time jobs.”
An indicator of how difficult is that the two agencies are separated geographically by more than 600 miles. NIH is located outside of Washington, DC, in Bethesda, Maryland, and the CDC is headquartered in Atlanta, Georgia.
Y. Tony Yang, a professor of health policy at George Washington University’s Milken Institute School of Public Health, agrees that it’s not a good idea to have the NIH director simultaneously run the CDC.
“NIH is a grant-making research behemoth; CDC is an operational, field-facing emergency-and-prevention agency,” he says. “Asking one person to run both at once is like asking someone to manage live flight traffic while also designing the planes.”
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