The director of the US Centers for Disease Control and Prevention (CDC) remains in a heated standoff with the Trump administration after the White House announced she had been fired.

Susan Monarez – who has only been in the job for a month – refused “to rubber-stamp unscientific, reckless directives” and accused Health Secretary Robert F Kennedy Jr of “weaponising public health”, according to her lawyers.

Her lawyer insisted Dr Monarez’s sacking was not legal and only President Donald Trump – not White House officials – could remove her.

The reason for her removal was that she was “not aligned with the president’s agenda”, the White House said in a statement.

At least three senior CDC leaders resigned from the agency, some citing frustration over vaccine policy and the leadership of Kennedy, also known as RFK Jr.

Among them was Chief Medical Officer Debra Houry, who warned about the “rise of misinformation” about vaccines in a letter seen by the BBC’s US partner CBS News. She also argued against planned cuts to the agency’s budget.

A long-time federal government scientist, Dr Monarez was nominated by President Donald Trump to lead the CDC and was confirmed in a Senate vote along party lines in July.

Her nomination followed Trump withdrawing his first pick, former Republican Congressman Dave Weldon, who had come under fire for his views on vaccines and autism.

On Wednesday, Dr Monarez’s lawyers issued a statement saying that she had chosen “protecting the public over serving a political agenda”.

The White House statement announcing the termination of her post said: “As her attorney’s statement makes abundantly clear, Susan Monarez is not aligned with the president’s agenda.”

On Thursday, Kennedy told Fox News that the CDC leadership “needs to execute Trump’s agenda”.

The CDC, he added, “is in trouble, needs to be fixed”.

The New York Times reports that she was at odds with Kennedy, a vaccine sceptic, over vaccine policy.

The exodus at the top of one of the world’s most foremost public health bodies comes as health experts voice concern over the agency’s approach to immunisations since Kennedy took over.

Senator Bernie Sanders, who is the ranking member of the Senate Health, Education, Labor and Pensions (HELP) said the sacking was “reckless” and “dangerous” and called for an investigation into the firing of Dr Monarez.

Daniel Jernigan, who led the National Center for Emerging and Zoonotic Infectious Diseases, was one of those to quit citing “the current context in the department”.

Head of the National Center for Immunization and Respiratory Diseases, Demetre Daskalakis, also said he was no longer able to serve “because of the ongoing weaponising of public health”.

There are also reports, including by NBC News, that Dr Jennifer Layden, director of the Office of Public Health Data, Surveillance and Technology, has also resigned.

Earlier on Wednesday, the Food and Drug Administration (FDA) approved new Covid vaccines while limiting who could receive them.

The vaccines will be available for all seniors, but younger adults and children without underlying health conditions will be excluded.

“The emergency use authorizations for Covid vaccines, once used to justify broad mandates on the general public during the Biden administration, are now rescinded,” Kennedy wrote on X.

Dr Monarez was the first CDC director in 50 years to not hold a medical degree. Her background is in infectious disease research.

In her month as the CDC leader, she helped comfort agency employees after the CDC’s headquarters in Atlanta was attacked by a gunman who believed he had been harmed by Covid vaccines.

The attack, in which hundreds of bullets struck the building, killed one police officer.

Earlier this month, current and former employees of the agency wrote an open letter accusing Kennedy of fuelling violence towards healthcare workers with his anti-vaccine rhetoric.

Dr Monarez’s departure comes about a week after a union representing CDC employees announced that about 600 CDC employees had been fired.

The wide-ranging layoffs included employees working on the government’s response to infectious diseases, including bird flu, as well as those researching environmental hazards and handling public record requests. (BBC)