More kids are hospitalized at Children’s Hospital Colorado because of COVID-19 now than at any previous point in the pandemic, a surge fueled by the omicron variant and affecting young children at high rates.

Patient volumes within the system are up across the board, from the emergency room to medical-surgical beds and the intensive care unit, infectious disease physician Sam Dominguez said Tuesday. He said the hospital believes it’s seeing so many patients now because of the sheer size of the omicron surge: Across Colorado, the variant’s arrival has shattered case and positivity rate records, and it has in short order overtaken the delta wave in terms of overall hospitalizations. 

Statewide, there’s early evidence that the situation overall may be improving: Cases are starting to decline, as is the positivity rate. But Dominguez said there’s been no such improvement at Children’s yet: The uptick began in late December, took off in January and has not slowed since.

According to the state Department of Public Health and Environment, the case rate for Coloradans under the age of 18 was 198 over the past two weeks. That’s more than triple the rate in December, which previously had the highest rate. Sixty-seven children statewide were hospitalized with the disease as of Tuesday.

The hospitalization rates for younger children – those younger than 5 years old – are also higher than in previous waves, he said. Children that young are not eligible to be vaccinated. The state health department said only 10% of the children hospitalized with COVID-19 were vaccinated. Recent federal data show that children too young to be vaccinated were being hospitalized with COVID-19 at rates nearing those of young adults, although they were still well below the rates for middle-aged people and seniors.

When vaccinations for 5- to 11-year-olds were first approved in early November, the state set a goal of vaccinating 50% of that age group by the end of January. As of Tuesday afternoon, 35% of that age group were partially vaccinated, and 26% were fully vaccinated. Two-thirds of 12- to 17-year-olds are partially vaccinated, while 59% are fully inoculated. The health department said Colorado is 15th in the nation for vaccinating 5- to 11-year-olds.

Colorado is not alone in seeing this surge: Omicron has sent case rates skyrocketing nationwide. Children younger than 5 are being newly hospitalized with COVID-19 at higher rates than at any point before in the pandemic, according to federal data. Like Dominguez, health officials elsewhere say the rising numbers among children are the result of the rapid spread of the omicron variant, which is much more easily transmitted than earlier variants of the coronavirus.

Young children and teens usually do not end up in the hospital from the coronavirus: Less than 1% of children and teens who have been infected have been hospitalized and 0.01% have died, according to cumulative data gathered from states by the American Academy of Pediatrics and the Children’s Hospital Association.

But with massive surges in infections, even a small percentage of kids being hospitalized has resulted in many more children in hospital beds than before. For the seven-day period that ended Jan. 12, the U.S. was averaging 881 newly admitted children and teens with COVID-19 per day; the rate of new hospitalizations among that group is six times higher than it was two months ago.

Like other hospitals across the state and country, some patients are turning up at Children’s with “incidental” infections – meaning they’re infected with the virus but are in the hospital for other reasons. But Dominguez said two-thirds of Children’s patients who are positive for the virus require hospitalization for it. 

“It’s a very large increase in the number of kids being admitted to the hospital,” he said.

He added that schools were “definitely … contributing to some of the spread,” and he advocated for continued masking and vaccinations for eligible kids.

Omicron broadly has shown to be less severe than delta and other strains of the virus that causes COVID-19. Dominguez said Children’s and other researchers are still looking into whether that holds true for pediatric patients, as well. He said it appears that patients’ infections in this wave are higher in their airways. Some early studies of omicron’s presentation indicates that it primarily affects those airways, rather than the lungs.  

Fortunately, Dominguez said, the “long and severe” RSV season has started to come down. RSV is also a respiratory illness that primarily affects children and can be severe. Like other, similar disease, it typically peaks in the winter months. But it surged in August, which several providers said was unprecedented. But it’s “definitely down,” Dominguez said. Flu season has also been relatively mild so far, he said, but that could change later this month or in February.

The Los Angeles Times contributed to this report.