But Dan Troy, a former chief counsel for the FDA during President George W. Bush’s first term, said that despite Kennedy’s lofty goals, there’s unlikely to be “seismic changes” within the agency. If Kennedy—or other members of Trump’s proposed cabinet—follow through with staff purges, they’ll lack the framework for altering the agency’s course, Troy argued.

“Who are you going to put in place?” he told Reuters. “Who has the technical expertise to write these rules that are going to really change the paradigm?” 

Kennedy, who has espoused complete falsehoods on vaccines risks, including the proven-untrue claim they cause autism, has boasted sweeping policy changes in his “Make America Healthy Again” (MAHA) plan. Those changes may include removing fluoride from tap water, despite evidence it helps fight tooth decay, and promoting the consumption of raw milk, which is associated with the bird flu outbreak in dairy cows, bacterial infections, and various parasites. 

In a Thursday X post thanking Trump for his nod, Kennedy said he plans to “clean up corruption, stop the revolving door between industry and government, and return our health agencies to their rich tradition of gold-standard, evidence-based science.” Trump, who endorsed MAHA, said he’ll let Kennedy “go wild on health.”

Kennedy and the FDA did not immediately respond to Fortune’s requests for comment.

Investors have already expressed panic over Kennedy’s prospective HHS spot. Share prices of Big Pharma companies plummeted Thursday following Trump’s decision, including Moderna, which fell 5%, and Novavax, which closed down 7%, on Thursday. Vaccine-makers lost over $8 billion in market value overnight.

Public health scramble

Troy’s dismissal of Kennedy as a profound public health threat is the contrarian opinion thus far, with FDA employees and public health officials sounding the alarms on the future of health agencies under Kennedy.

“If we were to come in and wholesale remove departments of public health and areas in public health, everyone in our country would be at risk,” Richard Besser, former acting director of the Centers for Disease Control and Prevention, told PBS shortly after the election.

He argued that drastic staff and department cuts would compromise the safety of food; the classroom safety of children, given they may be around unvaccinated peers; and increase the risk for individuals who may have cancer, as they would have less access to free screenings that could detect the disease early.

Dozens of FDA employees have considered leaving the agency as a result of Kennedy’s appointment, citing risks of post-employment restrictions and getting fired. But Dr. Peter Marks, the FDA’s top vaccine official, has taken a measured response to the prospect of Kennedy leading the HHS.

“What I would ask of him is that he keep an open mind,” he said this week during a Milken Institute event in Washington, D.C., prior to Trump’s decision. “We’re happy to try to show as much of the data as we can. And I think the data are essentially overwhelming, in certain areas, but we’ll just have to engage in the dialogue.”