At least three major health systems in Florida said half of their COVID-19 patients were originally admitted to hospitals for other reasons.

During a briefing about the pandemic in Jacksonville on Tuesday, Gov. Ron DeSantis said about 50% of COVID hospitalizations at Orlando Health and Miami Jackson Health and 60% at Tallahassee Memorial were being treated for other reasons and learned were positive for the virus during their stays.

In a tweet, Miami Jackson Health said its exact figure is 53%.

DeSantis called on the U.S. Department of Health and Human Services to change the way it reports COVID-19 hospitalizations.

"It really isn't instructive if you have something that is very widespread and mild, and it's catching people as they go into the hospital with positive tests, but they're not actually having any clinical diagnosis," he said.

It comes one day after New York Gov. Kathy Hochul said hospitals in her state would be surveyed about how many patients were being admitted to hospitals for COVID as opposed to with COVID.

-ABC News' Will McDuffie

The U.S. is recording 1,200 new COVID-19 deaths every day, up by about 10% in the last week, according to federal data.

Nearly 828,000 Americans have now died due to the virus. Just three weeks ago, the death toll surpassed 800,000.

Additionally, more than 112,000 Americans are currently hospitalized with COVID-19, with just under a fifth of those patients -- nearly 20,000 -- in intensive care units.

On average, more than 12,700 people in the U.S. are being admitted to hospitals with COVID-19 daily, a figure which has nearly doubled over the last month.

-ABC News' Arielle Mitropoulos

COVID-19 vaccines do not increase the risk of premature or low-weight birth among babies born to pregnant vaccinated women compared with those born to unvaccinated women, according to a new study from the Centers for Disease Control and Prevention published Tuesday.

Researchers from Yale looked at electronic health data from more than 40,000 pregnant women from the CDC's Vaccine Safety Datalink.

There were 7.0 premature births for every 100,000 babies born among unvaccinated women compared to 4.9 births per 100,000 for babies born to women who received a COVID vaccine while pregnant.

Additionally, rates of low-birth weight were 8.2 per 100,000 in both the unvaccinated and vaccinated groups.

The team said the findings add to a growing body of evidence that getting vaccinated against COVID is safe for pregnant people and for their babies.

Pregnant women are at increased risk for severe illness, hospitalization and death from COVID-19, but only 40% have been vaccinated, CDC data shows.

The omicron variant accounts for 95% of all new COVID-19 cases in the U.S., according to data from the Centers for Disease Control and Prevention released Tuesday.

In early December, the highly transmissible variant made up 0.6% of new infections.

Meanwhile, the delta variant -- responsible for the summer surge -- makes up 4.6% of new cases, the CDC said.

The data also showed the omicron variant is dominant in all regions of the country. In the New York-New Jersey region and in the Southeast, the variant is linked to 98% of new infections.

-ABC News' Arielle Mitropoulos

Dr. Rochelle Walensky, director of the U.S. Centers for Disease Control and Prevention, is standing by her agency's new quarantine and isolation guidance for COVID-19, which the nation’s largest association of physicians has criticized as "confusing."

The CDC updated its guidelines on Dec. 27, saying asymptomatic people who test positive for COVID-19 should self-isolate for five days rather than 10. In a scathing statement released Wednesday night, the American Medical Association (AMA) said the new recommendations "are risking further spread of the virus."

"The American people should be able to count on the Centers for Disease Control and Prevention (CDC) for timely, accurate, clear guidance to protect themselves, their loved ones, and their communities. Instead, the new recommendations on quarantine and isolation are not only confusing, but are risking further spread of the virus," the AMA's president, Dr. Gerald E. Harmon, said in the statement. "With hundreds of thousands of new cases daily and more than a million positive reported cases on January 3, tens of thousands -- potentially hundreds of thousands of people -- could return to work and school infectious if they follow the CDC’s new guidance on ending isolation after five days without a negative test."

But Walensky defended the new guidance, telling ABC News' Cecelia Vega in an interview Friday on "Good Morning America" that the CDC "make[s] these recommendations in the context of science, in the context of ongoing epidemiology and in the context of what is feasible in collaboration with our public health and local and state public health partners."

"I've read the AMA statement and I have deep respect for the AMA," Walenskey said, "but I will also say we've heard a lot of support for ongoing guidance from public health partners, from other clinical and laboratory partners as well."

Walensky referenced "dozens of studies" that have shown a COVID-19 patient is most infectious in the one to two days before symptoms and the two to three days after symptoms.

"So by five days after your symptoms, the vast majority of your contagiousness is really behind you," she said. "And what we say at day five then is, are your symptoms gone? Are you feeling better? Is your cough gone, sore throat gone? And if so, then it is safe to go out if you are wearing a mask all the time. And that means not going out to restaurants, not going out to gyms, not going out and visiting grandma, but really conscientiously wearing your mask for those last five days."

Walensky noted that people may choose to take an antigen or at-home test at day five, if they have access to one. But it's not required.

"If that test is positive, you should stay home for those extra five days. But if that test is negative you should go out and continue to wear your mask," she said. "You know, these tests are actually not authorized for the purpose of evaluating contagiousness."