(CNN) Children younger than 5 have between 10 and 100 times more genetic material from the novel coronavirus in their noses compared to older children and to adults, according to a small study published Thursday in the journal JAMA Pediatrics.

While the study didn't measure transmissibility, it raises questions -- just as schools start to reopen -- about how easily the new coronavirus may be spread by the under-5 set.

"We had just noticed that some of the children that we were testing for SARS CoV-2 that were positive, the youngest children seemed to have a high amount of the viral nucleic acid -- a high viral load in their nose -- compared to some of our older children and adults," lead author Dr. Taylor Heald-Sargent, a pediatric infectious diseases specialist at Lurie Children's Hospital of Chicago, told CNN. "And so when we ... actually ran the numbers, controlled for a few things, we found that there was actually a statistically significant higher amount of the genes that are encoded by SARS, which usually correlates to more virus, in the nose of children less than five years old, compared to older children and adults."

Heald-Sargent and her team analyzed 145 swab samples collected from patients with mild to moderate Covid-19 within a week of symptom onset; 46 of them were from children under 5, 51 were from 5- to 17-year-olds, and 48 were from adults between 18 and 65. The samples were collected between the end of March and the end of April from various inpatient, outpatient, emergency department and drive-through testing sites at a pediatric tertiary medical center in Chicago.

They found that those under 5 had a statistically significant greater amount of virus particles in the nose correlating to "a 10-fold to 100-fold greater amount of the coronavirus in the upper respiratory tract ... " the researchers wrote in their paper. Read more at CNN