Almost one-third of adolescents hospitalized with COVID-19 were admitted to an intensive care unit in January-March of this year, and 5 percent needed machines to help them breathe, the Centers for Disease Control and Prevention said in a report released Friday.

The agency’s Morbidity and Mortality Weekly Report showed that adolescent hospitalization rates had fallen in mid-March from a peak of 2.1 per 100,000 in January, but then rose again in April to 1.3 per 100,000.

The findings also showed that cumulative COVID–associated hospitalization rates for adolescents between October 2020 and April were as much as three times higher than flu-associated hospitalization rates from three recent influenza seasons.

The new data on adolescents reinforced the importance of continued COVID prevention measures, such as vaccination and wearing of masks if not fully vaccinated, the report said.

In a White House briefing on Thursday, CDC Director Rochelle Walensky described the COVID data on adolescents as “troubling,” and the force behind redoubling the agency’s motivation to get adolescents and young adults vaccinated.

In a statement Friday, Walensky said she is “deeply concerned” and saddened by the data and encouraged adolescents to continue to wear masks until they are fully vaccinated.

“Much of this suffering can be prevented,” she said.

Erin Sauber-Schatz, who leads the CDC’s Community Intervention and Critical Population Task Force, said last week that more than 2.5 million of those ages 12-15 in the U.S. have had their first dose since the Pfizer Inc. and BioNTech SE COVID-19 vaccine was authorized for their age group on May 10.

The report comes a week after the agency loosened its guidance for those attending U.S. summer camps, announcing that fully vaccinated campers will no longer need to wear masks or practice social distancing for the upcoming season.

— Bloomberg News