Up to one-third of children and teens hospitalized with the coronavirus disease 2019 (Covid-19) in the United States require treatment in the intensive care unit (ICU), a study published Friday by JAMA Network Open found.

In addition, about 20 percent of those admitted to a hospital ICU need mechanical ventilation support to maintain breathing, the data showed.

Although just over 10 percent of children and teens infected with coronavirus require hospitalization, the analysis suggests that those who do go on to develop severe disease.

“Some children develop serious illness that leads to hospitalization, use of invasive mechanical ventilation and death,” researchers from the U.S. Centers for Disease Control and Prevention wrote.

“Reducing infection risk through community mitigation strategies is critical for protecting children from Covid-19 and preventing poor outcomes,” they said.

Last year, more than 2 million of the nearly 30 million confirmed cases of Covid-19 in the United States involved children, according to the Centers for Disease Control and Prevention.

Other studies have shown that young people can develop serious complications from Covid-19, including heart problems and Kawasaki syndrome-like symptoms.

For this study, agency researchers reviewed data for about 21,000 of these pediatric patients, more than 2,400, or 12 percent, of whom were hospitalized.

Among children admitted to the hospital with the virus, 747, or 31 percent, needed ICU treatment and 172, or 7 percent, required mechanical ventilation.

Fifty-four percent of the children treated in hospital ICUs were male, as were just over 58 percent of those who needed ventilator support.

Based on their analysis, children and teens with a pre-existing, chronic health condition were more than three times as likely to develop severe Covid-19 compared to otherwise healthy young people.

Moreover, children ages 2 to 11 years were 53 percent more likely to develop severe disease, compared with those ages 12 to 18 years.

“Our analysis revealed an increased association of severe Covid-19 in younger children compared with older children,” the researchers wrote.

Admission to an intensive care unit for younger children may have less to do with disease severity and more to do with being cautious, the researchers said, and should be considered during clinical and resource planning decision-making.