(CNN) - While many questions about COVID-19 remain unanswered, a new study is confirming what doctors have already noticed since the novel coronavirus started infecting people: Children aren't getting as sick from the virus as adults.
Children in China with COVID-19 showed less severe symptoms than adults, but infants and toddlers were vulnerable to moderate and severe infection, according to a new study in the medical journal Pediatrics.
Researchers examined more than 2,100 confirmed and suspected cases of the novel coronavirus in children reported to the Chinese Center for Disease Control and Prevention.
Nearly 6% of those cases were severe and there was one death, compared to 18.5% of adults experiencing severe symptoms.
Young children, particularly infants, were more vulnerable than older children to COVID-19 infection, the researchers say.
For cases in infants less than one year old, nearly 11% were severe and critical.
More than 90% of all pediatric patients were asymptomatic, mild or moderate cases and about 13% of child patients who tested positive for the virus did not show symptoms of illness.
Researchers are still trying to determine why children with COVID-19 were not as sick as adults.
Earlier on Thursday, the U.S. Centers for Disease Control and Prevention reported that nearly 40 percent of patients in the U.S. who were sick enough to be hospitalized were between ages 20 and 54.
According to the CDC, COVID-19 symptoms typically appear two to 14 days after exposure and include fever, cough and shortness of breath.