Children’s noses may be better than adults’ at defending against infection because of “pre-activated” immunity against the coronavirus, a new study suggests.

Researchers analysed cellular gene expression in nasal swabs from 45 infected patients, including 24 children, and from 42 healthy individuals, including 18 children.

In epithelial and immune cells from the children’s swab samples, they saw higher levels of expression of pattern recognition receptor proteins that can sense the presence of viral RNA and trigger the immune system to defend against the pathogen.

Higher amounts of these sensors result in stronger early immune responses in children than in adults, according to a report published on Wednesday in Nature Biotechnology.