Children, teens and young adults are at greater risk for severe complications from COVID-19 than previously thought, and those with underlying health conditions are at even greater risk, according to a study coauthored by a Rutgers researcher.

The study, published in JAMA Pediatrics, is the first to describe the characteristics of seriously ill pediatric COVID-19 patients in North America.

“The idea that COVID-19 is sparing of young people is just false,” says study coauthor Lawrence C. Kleinman, MD, MPH, professor and vice chair for academic development and chief of the Department of Pediatrics’ Division of Population Health, Quality and Implementation Science at Rutgers Robert Wood Johnson Medical School. “While children are more likely to get very sick if they have other chronic conditions, including obesity, it is important to note that children without chronic illness are also at risk. Parents need to continue to take the virus seriously.”

The study followed 48 children and young adults—from newborns to 21 years old—who were admitted to pediatric intensive care units in the United States and Canada for COVID-19 in March and April. More than 80% had chronic underlying conditions, such as immune suppression, obesity, diabetes, seizures, or chronic lung disease. Of those, 40% depended on technological support due to developmental delays or genetic anomalies.

More than 20% experienced failure of two or more organ systems due to COVID-19, and nearly 40% required a breathing tube and ventilator. At the end of the follow-up period, nearly 33% of the children were still hospitalized due to COVID-19, with three still requiring ventilator support and one on life support. Two of the children admitted during the 3-week study period died.

“This study provides a baseline understanding of the early disease burden of COVID-19 in pediatric patients,” says Hariprem Rajasekhar, a pediatric intensivist involved in conducting the study. “The findings confirm that this emerging disease was already widespread in March and that it is not universally benign among children.”

The researchers said they were “cautiously encouraged” by hospital outcomes for the children studied, citing the 4.2% mortality rate for PICU patients compared with published mortality rates of up to 62% among adults admitted to ICUs, as well as lower incidences of respiratory failure.

Kleinman noted that doctors in the New York metropolitan area are seeing what appears to be a new COVID-related syndrome in children.

“Although our data collection for this study has ended, we continue to develop collaborations with colleagues in our region and across the country to try to understand these more severe complications,” he says, citing concerns such as heart failure and the Kawasaki disease–like condition termed pediatric multisystem inflammatory syndrome as examples.

Read more from Rutgers University and find the study in JAMA Pediatrics.