Children wait in line for health screenings before entering I.S. 136 Charles O Dewey School during the outbreak of the coronavirus disease (COVID-19) in the Sunset Park area of Brooklyn, New York, US, October 8, 2020. (Photo by Reuters)

The US Centers for Disease Control and Prevention’s (CDC) latest data shows that the highly transmissible omicron variant of COVID-19 is sending children to the hospital in record numbers.

Within weeks, Omicron has caused thousands of new COVID-19 hospitalizations among American children, according to the CDC.

The seven-day-average number of daily hospitalizations for children between Dec. 21 and Dec. 28, was the highest spike yet of COVID-19 hospitalizations for children, the CDC tracker showed.

More than 370 children are currently hospitalized daily, a 66 percent increase from the week prior.

Fewer than 25 percent of the 74 million Americans under 18 are vaccinated, according to the CDC. Doctors have told The Associated Press that low vaccination numbers among children during the outbreak are concerning, calling the omicron-fueled surge heartbreaking.

It was hard enough last year, but now you know that you have a way to prevent all this, Paul Offit with the Children’s Hospital of Philadelphia told the AP.

Tens of thousands of children have been hospitalized in the last few months. Experts have cautioned Omicron cases are expected to surge faster across the United States as schools reopen next week. Currently, there are winter holidays for children in the United States.

Doctors say Omicron’s extremely high transmissibility is one key factor that is driving up hospitalizations among children.

It is going to infect more people and it is infecting more people. We’ve seen numbers go up, we’ve seen hospitalizations in kids go up, said Dr. Jennifer Nayak, an infectious disease expert and pediatrician at the University of Rochester Medical Center, according to Reuters.

What we are seeing is that children under five remain unvaccinated so there’s still a relatively large population of children who are naive, so they have no preexisting immunity to this virus, said Nayak.

More than 1,000 children have died from COVID-19 in the United States since the pandemic began.

US health experts on Thursday urged Americans to prepare for severe disruptions in the coming weeks as the country reached a record high in COVID-19 cases.

The rising wave of COVID-19 cases led by the Omicron variant is crushing hospitals. For the second day in a row, the US saw a record number of new cases based on the seven-day average, with over 290,000 new infections reported each day, a Reuters tally showed.