(CNN) — As the Omicron variant spreads nationwide, leaving many people ill and forced to quarantine, educators and families are weighing the risks of allowing children to resume in-person classes.

The unprecedented surge has caused widespread staffing shortages and left more than 145,000 people in the US hospitalized with Covid-19 as of Tuesday, according to the Department of Health and Human Services — a record number for the pandemic.

Amid the disruption, those who work in education services have hotly debated whether in-person learning is currently feasible — and school districts across the country have taken different approaches after the holiday break.

LIVE UPDATES: The latest on the pandemic

Health experts are also urging more vaccination, with only 17% of children ages 5-11 and 54% of ages 12-17 immunized so far, according to the US Centers for Disease Control and Prevention.

One expert has told CNN that people need to stop thinking that the virus can’t harm children, because evidence to the contrary is mounting, while another said it’s safe enough to send kids to school.

The first, Dr. Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia, told CNN’s Jake Tapper on Tuesday that children are being infected at a much higher rate than in 2020.

More than 580,000 US pediatric Covid-19 cases were reported last week alone, far exceeding past peaks, the American Academy of Pediatrics and the Children’s Hospital Association said Wednesday.

That’s a 78% increase over the 325,000 new cases reported the prior week. And the last two weeks alone have accounted for 11% of the country’s total for pediatric cases, the groups said.

“Of the children who have been hospitalized or go to the intensive care unit or die, about a third of them have no comorbidities. Therefore, it can occur in anyone,” Offit said Tuesday.

“This is not a virus to fool around with. This is not influenza or parainfluenza or other typical respiratory viruses. This virus can cause you to make an immune response to your own blood vessels, which means that you can have heart disease, brain disease, kidney disease, lung disease as well as liver disease,” he said.

The second expert, Joseph Allen, director of the Healthy Buildings Program at the Harvard T.H. Chan School of Public Health, told CNN’s Erin Burnett on Tuesday that data shows risks to children are very low, and it’s now time to talk about easing measures such as mandatory masking.

Experts including Allen have said in-person learning should move forward, citing the eligibility of K-12 students for vaccines and that adult teachers and staff have had plenty of time to get inoculated and boosted.

“New data out of New York state during the peak of the Omicron surge shows that child hospitalization rates are on the order of 1 in 100,000 if you are unvaccinated. If you are vaccinated, a child’s risk is on the order of 2 to 3 per million,” Allen said.

“We are coming up on two years of disrupted school, kids in masks, to think there is no harm there or no loss in socialization, no impact, I think is incorrect,” he said. “The risk to kids is low and adults have had time to protect themselves with the vaccine.”

Pediatric Covid-19 hospitalizations across the country recently hit a pandemic high — at 5,018 children on Saturday, well beyond the peak of a Delta-variant-driven wave, which was 2,544 on September 10, according to HHS.

Among all ages, Covid-19 cases have exploded as the Omicron variant has spread.

The US averaged more than 747,260 new Covid-19 cases daily over the last week, according to Johns Hopkins University data. That’s about three times last winter’s peak average (251,987 on January 11, 2021), and about 4.5 times the peak from the Delta-driven surge (166,347 on September 1), according to JHU.

Deaths are also rising — but CDC director says this could be because of Delta variant

The country has averaged 1,715 Covid-19 deaths a day over the last week — 40% higher than a week ago, according to JHU. The peak average was 3,402 daily on January 13, 2021, JHU data shows.

CDC Director Dr. Rochelle Walensky said Wednesday she thinks the recent rise in Covid-19 deaths is still due to the Delta variant. Delta was the country’s predominant variant for months until Omicron overtook it in the week ending December 25, according to the CDC.

Changes in death rates usually lag behind case rates by a factor of weeks. “We will need to follow those deaths over the next couple of weeks to see the impact of Omicron on mortality,” Walensky said Wednesday during a White House Covid-19 response team briefing.

preprint study of data from California hospitals found that people infected with Omicron were less likely to be hospitalized — and for a shorter time — than those infected with Delta, and their risk of death was also lower.

The study, which was posted Tuesday and has not yet been peer-reviewed, analyzed data from people in the Kaiser Permanente Southern California health care system in December who tested positive for Covid-19, including about 52,000 infected with Omicron and 17,000 infected with Delta.

Of those people, 235 with Omicron and 222 with Delta were hospitalized. No patients with Omicron needed to be put on a ventilator, while 11 patients with Delta did.

Rates of admission to the ICU were four times less for those with Omicron compared with Delta, and rates of death for those with Omicron were about a tenth of those with Delta, according to the study.

More than 62,000 people could die of Covid-19 in the next four weeks, an ensemble forecast from the CDC published Wednesday predicts. Covid-19 has killed more than 842,300 people in the US, according to JHU.

As some schools return to class, others head home

As the debate continues over how schools can better mitigate the Omicron spread, some educators are taking matters into their own hands.

A group of teachers in Louisiana are planning a “sick-out” Wednesday to protest Covid-19 protocols and severe staff shortages, demanding virtual learning return in their district and for school officials to extend isolation times for those infected from five days to 10 days.

“We are asking that our teachers take off tomorrow and stand in solidarity showing that we care about our students, and we’re not going to allow them to be put in jeopardy,” said Valencea Johnson, president of the East Baton Rouge Parish branch of the Louisiana Association of Educators.

“Entire departments are out, buses and classrooms are being combined, ancillary staff, teachers, office staff, and other school employees are covering classes to keep the school afloat,” she said. “We cannot continue to do this. Our staff is experiencing burnout and our students are not getting the education they need and deserve.”

CNN has reached out to the superintendent of the district for response.

Several of the nation’s largest school districts are returning to in-person learning while others are shifting to remote.

Districts in Los Angeles, Chicago and Atlanta moved forward with returns to classrooms this week. Students at Chicago Public Schools will arrive to class Wednesday after a battle between the school system and the teachers’ union canceled classes for days.

Other districts, such as Cincinnati, Santa Fe and Las Vegas — where the Clark County school district is the fourth largest in the country — are temporarily moving back to remote learning as they deal with teacher absences.

The Biden administration, meanwhile, is set to give K-12 schools an additional 10 million Covid-19 tests per month, according to a government fact sheet.

The administration will distribute 5 million free rapid tests to schools each month, as well as 5 million free PCR tests each month through HHS’s expanded testing program.

The number still would cover just a fraction of students. Approximately 53 million students were in grades K-12 as of 2019, according to the US Census Bureau. And according to the CDC, Covid-19 screening should be offered for students at least once per week when community transmission is at moderate, substantial, or high levels.

HHS and the Federal Emergency Management Agency are also establishing surge testing sites in hard-hit communities.

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