Florida's top doctor took the extraordinary step Wednesday of calling for the halt of COVID-19 mRNA vaccine use, a move that contradicts federal health authorities and again makes Florida an outlier.

State Surgeon General Dr. Joseph Ladapo said in a statement released by the Florida Department of Health that he raised questions about the safety of the vaccines with the U.S. Food and Drug Administration and they did not provide an adequate response. As a result, he said he is now recommending against using the vaccines.

In response to Ladapo's announcement, the FDA reiterated the vaccine's safety and efficacy, pointing to last month's letter issued directly to Ladapo for an explanation it says dispells his concerns.

"The FDA stands firmly behind the safety, effectiveness and manufacturing quality of the approved and authorized COVID-19 vaccines, and respectfully disagrees with the Florida Surgeon General’s opinion," the FDA said in a statement shared with USA TODAY Thursday. "As stated in the letter, the challenge we continue to face is the ongoing proliferation of misinformation and disinformation about these vaccines which results in vaccine hesitancy that lowers vaccine uptake."

Lower vaccine rates contribute to illness and death caused by COVID-19, the FDA said.

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Who is Florida Surgeon General Dr. Joseph Ladapo?

Ladapo is a controversial figure who repeatedly has criticized COVID-19 vaccines and issued increasingly stringent recommendations urging various populations not to get them, despite assurances by federal authorities they are safe.

Nominated by Republican Gov. Ron DeSantis, Ladapo was confirmed along party lines by the state Senate in February 2022. He received a medical degree and doctorate in health policy from Harvard, and he holds a teaching position at the University of Florida.

Shortly after his confirmation, Ladapo made Florida the first state in the nation to recommend against healthy children receiving the COVID-19 vaccines. Then last year he recommended against anyone under the age of 65 getting new COVID vaccine boosters.

Since taking office, he has appeared on podcasts known for having conservative listeners or hosted by anti-vaccine advocates.

On the podcast "Liberty Lockdown," he called former chief White House medical advisor Dr. Anthony Fauci "a complete fraud when it comes to communication." During another appearance, he urged listeners to rely on their intuition when deciding whether or not to listen to medical doctors. His podcast appearances have drawn criticism and concern from medical experts.

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Dr. Ladapo raises concerns about COVID mRNA vaccines

Ladapo's latest recommendation is his most drastic yet, targeting some of the most popular vaccines such as those made by Pfizer and Moderna. Ladapo's letter to the FDA raises concerns about "the risks of contaminant DNA integration into human DNA" through the messenger RNA vaccine and "the integrity of the human genome.”

Messenger RNA, or mRNA, is a molecule that delivers genetic information from DNA to proteins. DNA "is the molecule that carries genetic information for the development and functioning of an organism," according to the National Human Genome Research Institute.

The Centers for Disease Control and Prevention says mRNA vaccines do not alter an individual's DNA: "None of the COVID-19 vaccines affect or interact with our DNA."

The FDA letter responding to Ladapo says, "We would like to make clear that based on a thorough assessment of the entire manufacturing process, FDA is confident in the quality, safety, and effectiveness of the COVID-19 vaccines."

It continues, "The agency’s benefit-risk assessment and ongoing safety surveillance demonstrate that the benefits of their use outweigh their risks. Additionally, with over a billion doses of the mRNA vaccines administered, no safety concerns related to residual DNA have been identified."

Dr. Ladapo on the campaign trail for presidential hopeful DeSantis

Ladapo has joined DeSantis on the presidential campaign trail and held various events with the governor in which scientists and medical professionals with contrarian COVID-19 views have criticized federal health authorities' management of the pandemic.

In 2023, when he advised against young men getting the mRNA vaccines, a task force of University of Florida medical school doctors concluded he was "cherry picking results," ignoring evidence that contradicted his bias and focusing on "exceptionally small event rates that distort magnitude of risk and do not consider magnitude of benefit."

According to a Health Department spokesman, Ladapo stood by his work.

Contributing: Jeffrey Schweers, Capital Bureau; Douglas Soule, Tallahassee Democrat; John Kennedy, Capital Bureau