Susan Monarez is no longer the director of the US Centers for Disease Control and Prevention, according to a post by the official Department of Health and Human Services X account. She had been in the position for just a month. In the wake of her apparent ouster, several other CDC leaders have resigned.

Named acting CDC director in January, Monarez was officially confirmed to the position by the Senate on July 29 and sworn in two days later. During her brief tenure, the CDC’s main campus in Atlanta was attacked by a gunman who blamed the Covid-19 vaccine for making him sick and depressed. A local police officer, David Rose, was killed by the suspect when responding to the shooting.

In a statement Wednesday evening Mark Zaid and Abbe David Lowell, Monarez’s lawyers, alleged that she had been “targeted” for refusing “to rubber-stamp unscientific, reckless directives and fire dedicated health experts.” The statement further says that Monarez has not resigned and does not plan to, and claims that she has not received notification that she’s been fired.

According to emails obtained by WIRED, at least three other senior CDC officials resigned Wednesday evening: Demetre Daskalakis, director of the National Center for Immunization and Respiratory Diseases; Debra Houry, chief medical officer and deputy director for program and science; and Daniel Jernigan, director of the National Center for Emerging and Zoonotic Infectious Diseases.

More resignations are expected to become public soon, say CDC staff with knowledge of the departures.

“I worry that political appointees will not make decisions on the science, but instead focus on supporting the administration’s agenda,” says one CDC employee, who was granted anonymity out of concerns over retribution. “I worry that the next directors will not support and protect staff.”

President Donald Trump’s original pick to lead the CDC was David Weldon, a physician and former Republican congressman from Florida who had a history of making statements questioning the safety of vaccines. But hours before his Senate confirmation hearing in March, the White House withdrew Weldon’s nomination. The administration then nominated Monarez.

The CDC leadership exits come amid recent vaccine policy upheaval fomented by HHS secretary Robert F. Kennedy Jr., who in May removed the Covid-19 vaccine from the list of the CDC’s recommended vaccines for healthy children and pregnant women. The following month, he fired all 17 sitting members of the CDC’s Advisory Committee on Immunization Practices, a group of independent experts that makes science-based recommendations on vaccines.

In their place, he installed eight new members, including several longtime vaccine critics. “A clean sweep is necessary to reestablish public confidence in vaccine science,” Kennedy said in a statement at the time.

Earlier this month under Kennedy’s leadership, HHS canceled a half billion dollars in funding for research on mRNA vaccines. This month HHS also announced the reinstatement of the Task Force on Safer Childhood Vaccines, a federal advisory panel created by Congress in 1986 to improve vaccine safety and oversight for children in the US. The panel was disbanded in 1998, when it issued its final report. Public health experts worry that the panel is a move to further undermine established vaccine science.