Sen. Bernie Sanders, I-Vt., is demanding that Health and Human Services Secretary Robert F. Kennedy Jr. resign after multiple senior officials at the Center for Disease Control and Prevention departed from the agency.

The Trump administration announced the removal of CDC Director Susan Monarez earlier this week, less than a month after she was confirmed, after she refused Kennedy’s directives to adopt new limitations on the availability of some vaccines, including for approvals for COVID-19 vaccines.

Four other senior CDC officials resigned in protest following Monarez’s ouster, pointing, in part, to anti-vaccine policies pushed by Kennedy. Hundreds of workers at the agency also walked out of the CDC’s headquarters in Atlanta in support of their former colleagues.

In response to the departures, Sanders wrote in an op-ed for The New York Times that Kennedy is “endangering the health of the American people now and into the future” and accused the secretary of firing Monarez because she refused “to act as a rubber stamp for his dangerous policies.”

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Sen. Bernie Sanders is demanding that Health and Human Services Secretary Robert F. Kennedy Jr. resign. (Chip Somodevilla/Getty Images)

“Despite the overwhelming opposition of the medical community, Secretary Kennedy has continued his longstanding crusade against vaccines and his advocacy of conspiracy theories that have been rejected repeatedly by scientific experts,” Sanders wrote in the piece published on Saturday.

“It is absurd to have to say this in 2025, but vaccines are safe and effective,” he added. “That, of course, is not just my view. Far more important, it is the overwhelming consensus of the medical and scientific communities.”

Sanders also noted that vaccines for diseases like polio and COVID-19 have saved hundreds of millions of lives around the world.

Sanders, the ranking member of the Senate’s health committee, opposed Kennedy’s confirmation earlier this year. The secretary was sworn in back in February. Deputy HHS Secretary Jim O’Neill was selected to be the acting director of the CDC after Monarez’s termination.

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Sanders said Kennedy is “endangering the health of the American people now and into the future.” (Reuters/Pedro Lazaro Fernandez)

The Trump administration has defended Monarez’s ouster, with White House press secretary Karoline Leavitt saying on Thursday that the president has the “authority to fire those who are not aligned with his mission.”

“The president and Secretary Kennedy are committed to restoring trust and transparency and credibility to the CDC by ensuring their leadership and their decisions are more public-facing, more accountable, strengthening our public health system and restoring it to its core mission of protecting Americans from communicable diseases, investing in innovation to prevent, detect and respond to future threats,” Leavitt told reporters.

Sanders earlier this week called for an investigation into Monarez’s ouster, criticizing the move as “reckless” and “dangerous.”

In the op-ed, he wrote that Kennedy “has profited from and built a career on sowing mistrust in vaccines,” adding that the secretary is now “using his authority to launch a full-blown war on science, on public health and on truth itself.” He also said it will become harder for Americans to obtain “lifesaving vaccines” with Kennedy leading HHS.

The Trump administration announced the removal of CDC Director Susan Monarez earlier this week. (Kayla Bartkowski/Getty Images)

“The danger here is that diseases that have been virtually wiped out because of safe and effective vaccines will resurface and cause enormous harm,” Sanders wrote, stressing that the U.S. needs to be better prepared in the case of another pandemic.

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“Secretary Kennedy is putting Americans’ lives in danger, and he must resign,” Sanders wrote. “In his place, President Trump must listen to doctors and scientists and nominate a health secretary and a C.D.C. director who will protect the health and well-being of the American people, not carry out dangerous policies based on conspiracy theories.”

Fox News Digital reached out to HHS for comment.

Reuters contributed to this report.