President-elect Donald Trump’s decision to tap Robert F. Kennedy Jr. as his health secretary has sent shock waves through the public health community, with experts warning the appointment could have dangerous consequences.

Trump has declared publicly that Kennedy will be given free rein to “Make America Healthy Again."

“Go have a good time, Bobby,” Trump said during his election night acceptance speech.

That’s exactly what has alarmed public health officials. RFK Jr. has no formal training in medicine or public health and has a history of peddling fringe theories. Some of them thoroughly debunked, like the idea childhood vaccines can lead to autism.

Speaking to NBC News shortly after the election, Kennedy said he doesn’t want top-down control. Instead, he says people should have a choice when it comes to vaccines.

“I’m not going to take away anybody’s vaccines,” he said in the NBC interview on Nov. 6. “I’ve never been anti-vaccine.”

Experts like Peter Muennig, a professor of health policy and management at Columbia University’s Mailman School of Public Health, worry that even a hands-off approach could trigger a public health crisis.

“We’re not talking about small numbers of people that are going to die,” Muennig said in an interview. “We’re talking about many thousands.”

Muennig said Kennedy could usher in the return of highly contagious diseases like measles and diphtheria.

“Being a role model for an anti-vax movement in that kind of government position will result, for sure, in drops in vaccination rates,” he said. “And that will result, for sure, in disease outbreaks.”

In his public remarks, RFK Jr. speaks largely about bringing down chronic disease, particularly among kids.

His criticisms of big pharma and the nutritional value of American food are widely embraced — including by Mayor Eric Adams, who last week declined to criticize the nomination.

“We have a real problem with our food in our country,” the Mayor said in an interview Friday on ABC’s “The View." “And we need to watch what we’re feeding our children.”

But RFK Jr. has also promised to clean up corruption at some of the agencies he’d oversee.

“In some categories, there are entire departments, like the nutrition departments at FDA, that have to go,” he told NBC.

Public health experts worry about the impact on existing safety regulations, like those that prevent food-borne illnesses. And they point to his promotion of unproven remedies like ivermectin.

“He has advocated,” Muennig said, “for consuming random and potentially dangerous medications that have proven to have no efficacy against the diseases he’s advocating using them for.”

It remains unclear whether RFK Jr. will have the votes to win Senate confirmation, even with a new Republican majority.