Drivers of heightened innate immunity in children
Children had less severe illness from COVID-19 than expected, and initial research on this phenomenon showed that children have heightened non-specific (“innate”) nasal immune responses compared to adults. By studying viruses, bacteria, and innate immune profiles in the noses of healthy and sick children, we found that frequent (but often not serious) viral and bacterial upper respiratory infections drive heightened states of innate immune defense in this age group. In people with COVID-19, better nasal defenses correlated with less severe infections. Our results suggest that heightened nasal defenses from frequent colds and other common infections may have helped protect young children against serious illness from COVID-19.