More than 300 children with COVID-19 are in Ohio hospitals, including Dayton Children's Hospital, where workers are seeing a significant increase in pediatric COVID-19-related hospitalizations.

Dr. Vipul Patel, chief of pediatric intensive care at Dayton Children's, told ABC News the ICU is now busier than at any other point in the pandemic.

COVID-19 is only exacerbating previously existing health issues for many children, Patel explained, adding that many parents are shocked to see their children become so sick, and some families have even expressed regret for not vaccinating their kids. Nationwide, about 35% of eligible children (ages 5 to 17) are fully vaccinated, according to federal data.

Dayton Children's respiratory therapist Hillary O’Neil said it's been particularly difficult to see children who are too young to understand what is happening sick and scared.

“You can see it in the faces of kids that can’t talk -- their eyes get really big and they, we watch them struggle to breathe,” O’Neil said. “Then on top of that we watch their parents struggle to watch their child, and that is sometimes just as hard as watching the kids.”

Jackie Kerby, whose baby, Enaeshya, is hospitalized with COVID-19, told ABC News, "She’s getting these fevers in the night, and they’re not coming down. … I am terribly scared."

Across the U.S. more than 5,000 children are currently hospitalized with a confirmed or suspected case of COVID-19, according to federal data. On average, hospital admissions among children have quadrupled over the last month.

-ABC News' Arielle Mitropoulos, Kayna Whitworth

New York state's COVID-19 cases are falling after experiencing a major surge over the holidays, according to state data.

New York recorded 60,374 new cases in the last 24 hours -- an improvement from New Year's Day when 85,476 daily cases were reporting during a spike in testing demands.

The Supreme Court has issued a stay of the vaccine-or-test requirement imposed on private businesses with at least 100 employees by the Occupational Safety and Health Administration.

In a 6-3 ruling, with the three liberal justices dissenting, the court finds likelihood the challengers will prevail and that OSHA exceeds its authority.

At the same time, the justices voted 5-4 to allow the Biden administration to require health care workers at facilities that treat Medicare and Medicaid patients to be vaccinated, subject to religious or medical exemptions.

-ABC News' Devin Dwyer

About 8,000 of Delta Air Lines' 75,000 employees had COVID-19 over the last four weeks, Delta CEO Ed Bastian told CNBC.

"Good news is that they were all fine. There's been no significant issues," he said.

"But it's knocked them out of the operation" amid the busiest travel season in two years, he said.

United CEO Scott Kirby said Tuesday that around 3,000 of United workers have COVID-19 right now.

Across the U.S., 3,783 TSA employees are currently at home with COVID-19, the agency said.

-ABC News' Mina Kaji, Sam Sweeney

Amidst the nation's most significant COVID-19 infection surge yet, new data released on Monday shows that more than half a million children tested positive for COVID-19, last week, according to a weekly report from the American Academy of Pediatrics and the Children’s Hospital Association.

Last week alone, 580,000 children tested positive for COVID-19, marking a nearly three times more than two weeks prior, according to the organizations.

A total of 8.47 million children have tested positive for the virus since the onset of the pandemic, and nearly 11% of these children have tested positive in the past two weeks alone.

Children accounted for about 17.3% of the reported weekly COVID-19 cases last week, down again from previous weeks, when children accounted for more than a quarter of all new cases. For context, children under 18 make up 22.2% of the U.S. population.

Still, recent COVID-19 data could be skewed due to erratic and volatile reporting following the holidays. An artificial increase in the numbers could have resulted as more Americans get tested.

-ABC News' Arielle Mitropoulos