Thousands of federal employees at the US Centers for Disease Control and Prevention were notified early Tuesday morning that they were subject to a reduction in force, or RIF, sources tell WIRED, shuttering programs that directly serve and inform the American public.

The effect was felt across the CDC, as workers in the Division of Environmental Health Science and Practice (DEHSP), the Division of Population Health, the Division of HIV Prevention, the Division of Reproductive Health, the National Institute of Occupational Safety and Health, and the National Center for Injury Prevention and Control all received RIF notices today.

Dozens of other programs throughout the CDC’s national centers for Chronic Disease Prevention and Health Promotion; HIV, Viral Hepatitis, STD, and Tuberculosis Prevention; Environmental Health; Immunization and Respiratory Diseases; and the Global Health center were also impacted.

Multiple sources in the Department of Health and Human Services, the agency that houses the CDC, say that RIF notices began going out around 5 am ET on Tuesday. Employees across HHS offices arrived at buildings only to discover that their badges no longer worked, sources tell WIRED.

“I regret to inform you that you are being affected by a reduction in force (RIF) action,” reads the email to affected employees. “This RIF does not reflect directly on your service, performance, or conduct. It is being taken solely for the reasons stated in the memorandum. After you receive this notice you will be placed on administrative leave and will no longer have building access beginning Tuesday, April 1, unless directed otherwise by your leadership.” The memorandum refers to the February 11 executive order from President Donald Trump titled “Implementing the President’s ‘Department of Government Efficiency’ Workforce Optimization Initiative.”

“The cuts today at CDC targeted programs that address all aspects of American lives,” a source at the CDC tells WIRED. “This will lead to worse health outcomes, greater risks to the US public, and will contribute to the decline in US life expectancy … programs that were eliminated fund positions across the country, in red and blue districts.”

“There has been no effort in allowing staff to transfer projects, programs, or responsibilities,” says one CDC staffer.

These cuts will have immediate impact, experts say. At the Division for HIV Prevention, where the stated mission is “to promote health and quality of life by preventing HIV infection and reducing HIV-related illness and death in the United States,” at least half of the employees received RIF notices.

“We’re going to have patients die,” says Jade Pagkas-Bather, an infectious disease doctor at the University of Chicago who also specializes in HIV prevention. “Unnecessary, preventable death.”

Joseph Cherabie, a physician and assistant professor in the division of infectious diseases at Washington University in St. Louis, says that these cuts will have devastating consequences for HIV patients around the country, especially in rural areas: “It will be catastrophic.”

Cherabie says that states relying heavily on federal funding for public health initiatives, like Missouri, where he works, will be hit especially hard. “We’re still seeing young people coming in with new HIV diagnoses, sometimes advanced HIV,” says Cherabie.

Along with six other states, Missouri has been awarded CDC funding dedicated to lowering HIV infections, which helps pay for medicine like pre-exposure prophylactics (PrEP) for at-risk patients. Cherabie says patients outside of cities heavily rely on these kinds of CDC-funded HIV programs.

“Our efforts are largely dependent on these federal grants,” he says. “We use them to make sure that we are able to distribute HIV testing equipment. We use them to make sure that we can get information and data on how much PrEP is being distributed, how many HIV diagnoses we have, how many HIV tests we’re giving out. If we lose that, then we’re moving around in the dark.”

An email from the CDC’s DEHSP center director states that the division is “slated to be eliminated in its entirety.” The division includes the Asthma and Air Quality Branch, the Climate and Health Activity, the Emerging Environmental Hazards and Health Effects Branch, the Environmental Public Health Tracking Branch, the Lead Poisoning Prevention and Surveillance Branch, and the Water, Food, and Environmental Health Services Branch. All of these branches provide key services, and hundreds of employees received RIFs.

Other divisions within DEHSP include, for example, the CDC’s Vessel Sanitation Program, which helps the cruise industry prevent public health issues, inspects cruises, and provides information on outbreaks. It’s unclear if the program’s work involving cruise inspections, or the lists of outbreaks on cruises, will continue. Similarly, the Lead Poisoning branch that works to eliminate childhood lead poisoning has also been gutted by RIFs. It’s unclear how much of its work will be able to continue.

The CDC cuts are part of the Trump administration’s plans to remove more than 10,000 Health and Human Services employees. Those sweeping reductions were “orchestrated” by Brad Smith, a member of Elon Musk’s so-called Department of Government Efficiency, according to Politico. The agency-wide cuts were originally expected to fall on Friday. In a press release last Thursday, HHS secretary Robert F. Kennedy Jr. announced that this restructuring, paired with early retirements and deferred resignations, would reduce the agency workforce from 82,000 to 62,000 full-time employees.

“Over time, bureaucracies like HHS become wasteful and inefficient even when most of their staff are dedicated and competent civil servants,” Kennedy said in a statement announcing the restructuring last week. “This overhaul will be a win-win for taxpayers and for those that HHS serves. That’s the entire American public, because our goal is to Make America Healthy Again.”

Anu Hazra, another infectious disease specialist at the University of Chicago who also works as a physician at the nonprofit medical clinic Howard Brown Health, says that cuts to CDC funding will severely curb the type of HIV prevention and testing he does, and potentially outright eliminate some of the services offered. “It’s the only way that the work gets done,” he says; he does not believe that other institutions will be able to compensate for the loss of federal funding. “The idea that you can just privatize public health, I don’t think it’s a realistic solution.”

Hazra says that funding cuts will disproportionately impact people like his patients on the South Side of Chicago, who come from socioeconomically disadvantaged Black communities that “either don’t have access or have really reduced access” to medical services including HIV prevention and treatment.

Several doctors WIRED spoke to were unnerved because President Donald Trump’s first administration had championed federal HIV prevention funding initiatives, which aimed to essentially end new HIV infections in the US by 2030, so they did not anticipate this radical change. “This work that we’re doing was thanks to him,” Hazra says.

“This is not just something that impacts people in the ivory tower. This is not just something that impacts people who are physicians, or scientists, or academics,” says Pagkas-Bather. “This is coming for you.”

Additional reporting by Emily Mullin.