The research, published in the journal PLOS Biology, suggests the nasal epithelium – or nose lining – of children inhibits infection and replication of the original and Delta strains of the virus that causes Covid-19.

Lead author Kirsty Short, from the University of Queensland, said the paper found children had a lower infection rate and milder symptoms than adults.

However, the anti-viral strength of the nose lining did not provide the same protection against the more infectious Omicron strain.

Researchers obtained samples of nasal lining cells from 23 healthy children aged 2-11 and 15 healthy adults aged 19-66 in Australia.

They exposed the cells of adults and children to SARS-CoV-2, which causes Covid-19, and then observed the “infection kinetics” and “antiviral responses in children compared to adults”.

The scientists said more clinical studies would be needed as the sample size was small.

“We have provided the first experimental evidence that the paediatric nasal epithelium may play an important role in reducing the susceptibility of children to SARS-CoV-2,” the authors said.

Last month, the country’s chief medical officer Professor Paul Kelly issued a fresh warning about the increase in Covid-19 cases across Australia.

Nearly 12,000 virus-related deaths have been recorded in the country since the start of the pandemic.

The vast majority have been people aged 70 and older, however 15 deaths have been registered among children aged nine or under.