Children age 2 or older who met the criteria for obesity were three times more likely to require a ventilator to treat their disease than those who had a healthy weight, the study found.
However, severe disease caused by the new coronavirus, SARS-CoV-2, remains relatively rare in young people, a similar study out of Wuhan, China -- also published Wednesday, by JAMA Network Open -- has found.
"While most children and adolescents have mild disease, a small percentage with underlying conditions have severe respiratory disease, which is associated with higher levels of inflammation," Dr. Philip Zachariah, co-author of the New York City study, told UPI.
"Even within young people, there is a spectrum of disease, both in terms of presentation and severity," said Zachariah, who is an assistant professor of pediatrics at Columbia University Medical Center.
Both studies echoed the findings of a study published earlier this week in the journal Pediatrics, which indicated that the vast majority of children with COVID-19 -- more than 90 percent -- experience mild to moderate illness, with few if any symptoms.
However, it is the "minority who are likely to worsen" who should be the focus of future research to learn the effects of COVID-19 on children, Zachariah said.
For their research, he and his colleagues reviewed data on 50 COVID-19 patients at a children's hospital in New York City. In all, 27 of the patients were boys and 25 were Hispanic, the authors said.
The estimated time between symptom onset and hospital admission was two days, according to the authors. Overall, 40 had fever and 32 had respiratory symptoms, but three only developed gastrointestinal problems, they said.
Obesity was the most prevalent underlying health condition among the 50 patients, affecting 11 of them, and six of these children required ventilation, the authors said. Among all 50 patients, 16 required respiratory support, including nine who needed mechanical ventilation, they said.
However, six of the nine children age 2 or older who were obese needed ventilator support, compared to only one of five non-obese children, the authors reported.
Children with severe disease had significantly higher levels of biomarkers -- or signs -- of inflammation, including C-reactive protein, procalcitonin, interleukin 6, ferritin and D-dime, according to the authors.
Four of the patients in the study had measurable levels of the virus in their systems for up to 27 days, based on test findings, the authors said.
Similarly, the study out of Wuhan, which included 157 children with COVID-19, found elevated levels of several inflammatory biomarkers -- including interleukin 10 -- and reduced white blood cell counts in those with moderate or severe disease.
In all, six of the children developed severe disease and three became critically ill, the Chinese authors said, adding that two of the three critically ill patients had cancer.
Where the studies differed, however, was in their respective findings on the age of children more adversely affected by COVID-19. In China, children with moderate disease were younger than those with mild cases -- 66 months versus 84 months.
Conversely, in the New York City study, there were 14 infants -- children 1 year old or younger, and none of them developed severe disease.
"[We] did not find severe COVID-19 being associated with infancy, which has been reported previously," Zachariah said.