The Food and Drug Administration’s top vaccine official, Peter Marks, resigned on Friday, citing what he called Health and Human Services Secretary Robert F. Kennedy Jr.’s "misinformation and lies" against immunization efforts. 

Marks, who played a key role in President Donald Trump's Operation Warp Speed to develop Covid-19 vaccines, stepped down from his position as the director of the FDA’s Center for Biologics Evaluation and Research, the division responsible for making sure vaccines are safe and effective, along with gene therapies and blood products. 

"I was willing to work to address the Secretary’s concerns regarding vaccine safety and transparency," Marks wrote in a letter addressed to acting FDA Commissioner Sara Brenner. "However it has become clear that truth and transparency are not desired by the Secretary, but rather he wishes subservient confirmation of his misinformation and lies." 

Kennedy has openly questioned the safety of vaccines for years. Just a week after his appointment as health secretary, a key advisory committee meeting on vaccine experts was delayed. He has also announced plans to study links between vaccines and autism. He has also faced criticism for his handling of the measles outbreak in Texas and New Mexico. 

"The ongoing multistate measles outbreak that is particularly severe in Texas reminds us of what happens when confidence in well-established science underlying public health and well-being is undermined," said Marks. "The vaccine very simply does not cause autism, nor is it associated with encephalitis or death."

Marks put in his papers after he was given the choice to resign or be fired, the Wall Street Journal, which first reported Mark's departure, said. His resignation comes a day after the Department of Health and Human Services announced plans to lay off as many as 10,000 full-time employees across multiple agencies. 

"Undermining confidence in well-established vaccines that have met the high standards for quality, safety, and effectiveness that have been in place for decades at FDA is irresponsible, detrimental to public health, and a clear danger to our nation’s health, safety, and security," said Marks. 

Marks, whose resignation is effective April 5, has been the director of the center since 2016. 

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