Almost 90% of U.S. children hospitalized for Covid during the omicron wave this winter were unvaccinated, according to a government study.

Omicron caused a record-breaking number of pediatric hospitalizations from December to February, and national data on hundreds of kids aged 5 to 11 highlight the importance of vaccinating them, the Centers for Disease Control and Prevention said in the report.

“Increasing vaccination coverage among children, particularly among racial and ethnic minority groups disproportionately affected by Covid-19, is critical to preventing Covid-19-associated hospitalization and severe outcomes,” the CDC said.

Though omicron has generally been considered milder than prior variants, …