• Posted April 16, 2024

Nosing Out Why Kids Are Less Harmed by COVID

The nose appears to know when it comes to why children typically have milder cases of COVID-19 than seniors, a new study finds.

Cells lining the inside of the nose are more likely to have a prompt immune response to COVID in young people than in old people, laboratory results show.

This enhanced response occurred even when researchers screened out the immune cells that would naturally exist alongside the cells lining the nose, which are called nasal epithelial cells, researchers said.

"It is fascinating that when we take away immune cells from nasal samples, and are only left with nasal epithelial cells grown in a dish, we are still able to identify age-specific differences in our body's response to [COVID] SARS-CoV-2 between the young and elderly to explain why children are generally protected from severe COVID-19,"said co-senior researcher Dr. Marko Nikolic, a respiratory specialist with the University College London Division of Medicine.

For the study, researchers cultured nasal cells donated from healthy children, adults and seniors.

The cell cultures were then exposed to the COVID coronavirus, and their responses tracked in the lab.

After three days, the nasal cells of children responded promptly to the virus by increasing interferon, a signaling protein that serves as the body's first line of defense against invading viruses. Interferons cause nearby cells to heighten their own anti-viral defenses, boosting immune defense.

However, this early anti-viral response became less pronounced with age. In fact, the nasal cells of seniors tended to produce more infectious viral particles, aiding in the spread of the virus throughout the body.

The stronger antiviral response in children's nasal cells could explain why younger people have milder COVID symptoms, researchers said.

Further, the increased damage and higher viral replication found in the nasal cells of seniors could show why they are at greater risk for severe COVID infections.

Children with COVID rarely suffer from respiratory failure requiring ventilation. On the other hand, those older than 85 are at great risk of dying from COVID, even with vaccination.

"Our research reveals how the type of cells we have in our nose changes with age, and how this affects our ability to combat SARS-CoV-2 infection,"lead researcher Claire Smith, an associate professor with the University College London Great Ormond Street Institute of Child Health, said in a news release.

"This could be crucial in developing effective anti-viral treatments tailored to different age groups, especially for the elderly who are at higher risk of severe COVID-19,"Smith added in a university news release.

Future studies should consider how aging affects the body's response to other viral infections, the researchers concluded.

The new study was published April 15 in the journal Nature Microbiology.

More information

The U.S. Centers for Disease Control and Prevention has more about COVID.

SOURCE: University College London, news release, April 15, 2024