(CNN) — More than 103,000 people are currently hospitalized with Covid-19, the first time the total has reached six figures in nearly four months, according to the latest data from the US Department of Health and Human Services.

Covid-19 hospitalizations reached a record high of more than 142,000 about a year ago, on January 14, 2021, and last topped 100,000 on September 11. The total fell to about 45,000 hospitalizations in early November, but increased steadily since then, and surged in the last week. Just last Monday, HHS reported 71,000 Covid-19 hospitalizations.

States also are reporting surges in the number of children hospitalized. In Illinois, that number has almost tripled since the beginning of December, Gov. J. B. Pritzker said Monday. New Jersey Health Commissioner Judy Persichilli said the total number of pediatric hospitalizations in that state has almost doubled in seven days.

Data published from the US Centers for Disease Control and Prevention and the Department of Health and Human Services last week showed that pediatric hospital admissions had reached a record high.

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The hospitalizations are primarily among unvaccinated people. According to the latest CDC data, cumulative hospitalization rates through November are about eight times higher for unvaccinated adults and about 10 times higher for unvaccinated children ages 12 to 17.

The rise in hospitalizations comes amid a much larger surge in Covid-19 cases spurred by the Omicron variant. Although early studies have suggested Omicron causes milder illness, the variant has spread so quickly and widely, hospitals are still facing challenges providing proper care.

“This narrative that it’s just a mild virus is not accurate,” Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine, said Monday.

“We’ve just done a terrible job vaccinating our kids across the country… So even though there’s a lot of happy talk about the Omicron variant, less severe disease, when you add up all the factors… we’ve got a very serious situation facing us in this country, especially for the kids.”

Dr. Anthony Fauci told CNN’s Dana Bash on “State of the Union” on Sunday that with so many cases, “even if the rate of hospitalization is lower with Omicron than it is with Delta, there’s still the danger that you’re going to have a surging of hospitalizations that might stress the health care system.”

Dr. James Phillips, chief of disaster medicine at George Washington University Hospital, said that has come to pass.

“We’re seeing a surge in patients again, unprecedented in this pandemic,” he said. “What’s coming for the rest of the country could be very serious. And they need to be prepared.”

Return of school adds new worries

The resumption of school on Monday after the holiday break has also led to concerns about further spread.

In Atlanta, at least five metro-area school districts will begin with remote learning this week, as students prepare to return from the holiday break amid rising cases in the region. In Washington, DC, public schools will be closed until Thursday as a winter storm thwarted plans for students and staff to pick up Covid-19 tests.

Other school officials are also changing their Covid-19 policies due to the explosion of the Omicron variant. The New Orleans school district added the Covid-19 vaccine to its list of required immunizations for all students 5 and older, effective February 1.

Miami-Dade County Public Schools is requiring all adults entering its buildings and buses to wear masks upon return and has strongly encouraged students to wear masks as well. Public schools in Detroit are closed Monday through Wednesday as the city faces an all-time high Covid-19 infection rate.

Los Angeles Unified students will be required to show proof of a negative Covid-19 test before returning to school after the winter break, the district told parents in an email Monday. The district also pushed back the return by a day.

Dr. Stanley Spinner, chief medical officer at Texas Children’s Pediatrics, told CNN’s Pamela Brown, “When our largest school system gets back, I think we are going to see our numbers increasing even more unfortunately as a result of that.”

While there may be “bumps in the road” as schools attempt to reopen in the new year amid a record surge in Covid-19 cases, Secretary of Education Miguel Cardona said students have suffered enough and need to be back in class.

“Our expectation is for schools to be open full-time for students for in person learning,” Cardona said on Fox News on Sunday, noting the science has improved nearly two years into the pandemic and vaccines are available for school-aged children. “There’s a level of urgency that we shouldn’t lose around making sure that our children learn in person.”

Many students are now eligible for booster shots. The US Food and Drug Administration authorized Pfizer’s Covid-19 vaccine for booster shots in 12- to 15-year-olds on Monday. About half of the 12 to 15 population is fully vaccinated.

Despite the push to keep schools open, some teachers have instead pushed to move to remote learning until this wave subsides. In Massachusetts, teachers called for state officials to close schools during the worst of the surge, but were rebuffed by the education commissioner and Gov. Charlie Baker.

“There are a lot of tools and capabilities available to keep kids and adults safe in school, and we should do everything in our power to make sure that kids stay in school,” Baker said, while also highlighting the state’s test and stay program.

The picture was similar in New York City, where new mayor Eric Adams felt schools must remain open and rejected a request from the teachers union to begin the month with remote learning until the current wave of the virus subsides.

Getting children back to school is a “precious thing,” said Dr. Paul Offit, director of the Vaccine Education Center at the Children’s Hospital in Philadelphia.

“And because it’s a precious thing, we need to treat it preciously, meaning arm those children with the two things we have that can protect them,” which are masking and vaccination, Offit told CNN’s Erin Burnett on Monday.

Hospitalizations rise as health care services are stretched thin

Health care workers have been exhausted by several surges since the pandemic began, and now many are getting sidelined during the rapid rise of the Omicron variant — the most contagious strain to hit the US.

“Our health system is at a very different place than we were in previous surges,” emergency medicine professor Dr. Esther Choo said.

“This strain is so infectious that I think all of us know many, many colleagues who are currently infected or have symptoms and are under quarantine,” said Choo. “We’ve lost at least 20% of our health care workforce; probably more.”

The University of Maryland Capital Region Health this week joined a growing list of medical centers in the state to activate emergency protocols after a sharp rise in cases fueled staffing shortages and overwhelmed emergency departments.

“The current demand for care is depleting our available resources, including staffing,” UM Capital Region Health said in a statement Friday.

There is also concern that while Omicron may be a milder form of coronavirus for adults, it could pose a greater risk to children, according to Dr. Scott Gottlieb.

“It appears to be more of an upper airway disease than a lower airway disease. That’s good for most Americans. The one group that that may be a problem for is very young children — toddlers — who have trouble with upper airway infections,” Gottlieb told Margaret Brennan on CBS’ “Face the Nation.

“You’re in fact seeing more croup-like infections and bronchiolitis in New York City among children. So that could be a challenge for young kids, and we are seeing rising hospitalizations among that pediatric segment,” said Gottlieb, a former commissioner of the US Food and Drug Administration and a current board member at Pfizer.

At Columbia University Irving Medical Center in New York, health care workers are seeing “more Covid now than we have seen in previous waves,” Dr. Edith Bracho-Sanchez, a primary care pediatrician and assistant professor of pediatrics at the center, told CNN’s Anderson Cooper Monday.

“This is not the time to minimize Covid-19 as an illness in children.,” Bracho-Sanchez said. “This is now the time to take every tool we have and use it to protect those kids like your son, like my son, who cannot get vaccinated yet.”

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