The receptors that let the virus inside cells are more common in the noses of adults than children, according to a report published in the Journal of the American Medical Association.
Researchers from the Icahn School of Medicine at Mount Sinai looked at nasal samples from around 300 people ages 4 to 60 — which were taken for an earlier, unrelated study on asthma.
In the new study, the samples were evaluated for the expression of the ACE2 gene, which the virus uses as a receptor to invade the body.
The expression of the gene in the cells lining the nose was lowest in younger children, while it was significantly higher in the other age groups and rose with age, the researchers said.
“Lower ACE2 expression in children relative to adults may help explain why COVID-19 is less prevalent in children,” the researchers wrote.
However, the researchers noted that the study had limitations because there were no samples from people above 60 — one of the most vulnerable groups for the virus.
The report comes as the virus has infected more than 1.5 million Americans, resulting in at least 93,000 deaths, according to the latest figures from Johns Hopkins University.