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

The United Kingdom has launched a new advertising campaign that urges pregnant women who have not yet received a COVID-19 vaccine or booster shot to do so as soon as possible.

Testimonies of pregnant women who have had the shots will be played out in ads across U.K. radio stations and on social media starting Monday. The new campaign urges pregnant women "don't wait to take the vaccine" and highlights the risks of COVID-19 to both mother and baby as well as the benefits of getting vaccinated, according to a press release from the U.K. Department of Health and Social Care.

The press release cited the latest data from the U.K. Health Security Agency that suggests COVID-19 vaccination is safe for pregnant women and provides strong protection against the virus for both mother and baby. The press release also cited data from the U.K. Obstetric Surveillance System that shows more than 96% of pregnant women hospitalized with COVID-19 symptoms between May and October 2021 were unvaccinated, and a third of them required respiratory support. Around one in five women who are hospitalized with COVID-19 need to be delivered preterm to help them recover, and one in five of their babies need care in the neonatal unit.

"Getting a COVID-19 vaccine is one of the most important things a pregnant woman can do this year to keep herself and her baby as safe from this virus as possible," Lucy Chappell, chief scientific adviser to the U.K. Department of Health and Social Care, said in a statement Monday. "We have extensive evidence now to show that the vaccines are safe and that the risks posed by COVID-19 are far greater."