U.S. schools struggle to reopen amid Omicron wave

Thousands of U.S. schools delayed returning to classrooms or switched to remote learning after the holiday break, as the Omicron variant pushed COVID-19 cases to record levels.

Milwaukee, Cleveland and Detroit were among those who either moved classes online or canceled school altogether.

New Jersey had some of the highest case numbers in recent weeks.

Most urban school districts there implemented virtual classes to start the new year, including in Newark, the state's largest city.

But other hard-hit school districts pressed on with plans to reopen like in New York City, where one in every three COVID-19 tests were positive for the virus over the last week, according to city data.

"It's a little scary, but at least he gets to not be stuck in the house all day. So that's another thing."

In his first week on the job, New York City Mayor Eric Adams vowed to keep the nation’s largest school district open despite the surging virus.

"We are going to keep our schools open and ensure that our children are safe in a safe environment. If you look last year and 2020, you witnessed that the transmission rate was less than one percent inside a school. In the household, it was over 15 percent."

Meanwhile, in Washington, D.C., all staff and 51,000 public school students must upload a negative test result to the district's website before coming to class on Wednesday.

Medical officials continue to urge vaccinations, as the U.S. Food and Drug Administration authorized the Pfizer booster shot earlier this week for children ages 12 to 15.

Dr. Jennifer L. Lighter is a pediatric infectious disease specialist at a New York University Medical Center.

"It is very upsetting as a pediatric infectious disease doctor to see children in the hospital with COVID because 99 percent of the hospital admissions can be prevented if children were just fully vaccinated, and only 14 percent of children in the United States between ages five and 12 have been fully vaccinated. So, we need to do more in making sure our children are protected from severe disease and vaccinated."

Hospitalization rates for those under 18 soared in the final weeks of 2021.