Washington- The Trump administration initiated mass layoffs of over 10,000 employees across US health agencies on Tuesday. According to multiple sources, some employees were barred from entering their workplaces just hours after receiving dismissal notices.

The cuts impact several high-profile agencies under the Department of Health and Human Services (HHS), including the Food and Drug Administration (FDA), Centers for Disease Control and Prevention (CDC), and National Institutes of Health (NIH). This move aligns with President Donald Trump and billionaire Elon Musk’s broader plan to shrink the federal government and reduce spending.

Health Secretary Robert F. Kennedy Jr. defended the layoffs, calling them an “essential reform” to streamline bureaucracy. However, the decision has raised concerns, as it includes the removal of key scientists overseeing public health, cancer research, and vaccine and drug approvals, potentially weakening the nation’s ability to respond to health emergencies such as the ongoing measles outbreak and avian flu spread.

“Our hearts go out to those who have lost their jobs,” Kennedy posted on X (formerly Twitter). “But the reality is clear—what we’ve been doing isn’t working. It’s time to refocus HHS on its core mission: preventing chronic diseases.”

Among those affected, Peter Stein, director of the FDA’s Office of New Drugs, resigned rather than be dismissed. Brian King, head of the Center for Tobacco Products, was fired, as was Peter Marks, the FDA’s top vaccine expert.

Former FDA Commissioner Robert Califf wrote on LinkedIn, “The FDA as we knew it is gone. Most of its experienced leaders, with deep institutional knowledge, are no longer there. History will judge this as a major mistake.”

At NIH, employees were informed early Tuesday morning that they had been laid off. The director of the National Institute of Allergy and Infectious Diseases (NIAID), Jeanne Marrazzo, was dismissed and offered a position in the Indian Health Service.

At CDC, layoffs included staff from the National Center for Environmental Health, the Substance Abuse and Mental Health Services Administration, and the National Center for Immunization and Respiratory Diseases. One of the fired employees was involved in the federal response to the measles outbreak.

Outside NIH’s Bethesda campus and HHS headquarters in Rockville, long lines of staff awaited instructions, unsure if they would still have jobs. At some locations, security guards were tasked with informing employees of their termination and issuing dismissal tickets.

Health policy experts warn that these layoffs could severely weaken the nation’s ability to respond to public health crises.