(The Hill) — A leading vaccine official at the Food and Drug Administration (FDA) has stepped down, citing concerns over Health and Human Services (HHS) Secretary Robert F. Kennedy Jr.’s spread of “misinformation” and an apparent lack of interest in “truth and transparency.”

Dr. Peter Marks, who was in charge of the FDA’s Center for Biologics Evaluation and Research (CBER), resigned on Friday. He was reportedly presented with the option to either resign or be fired, as noted by multiple sources. The Wall Street Journal was the first to cover his resignation.

Marks said that he was “willing” to work to address Kennedy’s “concerns” about vaccine transparency and safety. 

In his resignation letter, addressed to the acting FDA Commissioner Sara Brenner, Marks expressed, “It has become evident that the Secretary is not interested in truth and transparency, but instead seeks compliance with his misinformation and falsehoods,” as noted in his statement on Friday.

The Hill has reached out to the FDA for comment. 

Marks has been at the FDA since 2012. In 2016, he became the director of CBER, the center responsible for the safety of “vaccines, allergenic products, blood and blood products, and cellular, tissue and gene therapies.” 

Marks, who got his graduate degree in cell and molecular biology, and medical degree at New York University, was instrumental in helping authorize the first vaccines against COVID-19 and played a major role in kickstarting Operation Warp Speed during President Trump’s first term.  

The top FDA official also criticized Kennedy on Friday over “undermining” the confidence in the vaccine against measles as the country faces an outbreak of the airborne viral disease. There are at least 400 confirmed cases in Texas. 

“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,” Marks wrote in the letter that was obtained by The New York Times. 

Since taking the helm of HHS, Kennedy has worked to reshape the outlook department, looking to dismiss 10,000 workers as part of a restructuring effort, while another 10,000 would be cut through buyouts and early retirements. 

The HHS secretary defended the upcoming cuts, saying on The Hill’s partner that the agency is “not cutting front-line workers, we’re cutting administrators, and we’re consolidating the agency to make it more efficient.”

“My hope is that during the coming years, the unprecedented assault on scientific truth that has adversely impacted public health in our nation comes to an end so that the citizens of our country can fully benefit from the breadth of advances in medical science,” Marks said in the 2-page letter. 

Kennedy said the National Institute of Health has a division that is “devoted” to studying long COVID and that the HHS is incorporating an agency within the Centers for Disease Control and Prevention that will “specialize in vaccine injuries.”  

“Those are things that are priorities for me, and also Lyme disease. These are priorities for the American people,” Kennedy told host Chris Cuomo. “More and more people are suffering from these injuries, and we are committed to having gold standard science to make sure that we can figure out what the treatments are and that we can deliver the best treatments possible with the American people.”