Children with COVID-19 are hospitalized infrequently compared with adults, but the rate has been growing and about a third of those hospitalized in a subset of a federal study published Friday needed intensive care.

The study by the U.S. Centers for Disease Control and Prevention analyzed pediatric hospitalization data for 576 cases in 14 states. It found that about eight children are hospitalized for every 100,000 infected, compared with more than 164 adults per 100,000.

But between March and July, the hospitalization rates of children increased steadily, with Black and Latino children hospitalized at a higher rate. Among 208 hospitalized children with complete medical chart reviews, a third were admitted to an intensive care unit. One died and 12 needed invasive ventilation.

The report comes as President Donald Trump has pushed for schools to reopen across the U.S., and many large districts have pushed back.

Continued surveillance is needed to further identify “the burden and outcomes of COVID-19-associated hospitalizations among children,” the researchers wrote in the report. “These data will help to better define the clinical spectrum of disease in children and the contributions of race and ethnicity and underlying medical conditions to hospitalizations and outcomes.”

While children do appear to be at a lower risk of getting very ill, a small number have died or required intensive care as a result of either the respiratory failure commonly associated with the virus or a frightening inflammatory condition sometimes described as similar to Kawasaki disease that causes heart or circulatory problems.