The Covid-19 pandemic may have indiscriminately affected people of all age groups but the most vulnerable candidates were the elderly. The reason why children were less severely infected than the senile population above the age of 60, was because of their nasal cells.
A recent study by University College London and the Wellcome Sanger Institute discovered that cells in the nasal lining of children have a better defense against the SARS-CoV-2 virus, which might explain why they usually have milder symptoms.
Scientists grew nasal cells from three age groups: children under 12, adults aged 30 to 50, and people over 70. Then, they exposed these cells to the Covid-19 virus.
The results, published in Nature Microbiology, showed that children’s nasal cells fought off the virus quickly, while this ability weakened with age.
The nasal epithelial cells (NECs) from older adults had more virus and showed more damage.
Although children rarely get very sick from Covid-19, older people, especially those over 60, still face high risks, even with vaccines and better treatments.
This study highlights the importance of considering age when studying and treating infectious diseases.
“Our research shows how age affects our nasal cells’ ability to fight off SARS-CoV-2. This could help develop treatments and prevention strategies tailored to different age groups, especially for older adults who are at higher risk of severe illness,” said Dr Claire Smith, who led the project at UCL.
Children infected with SARS-CoV-2 rarely progress to respiratory failure, but the risk of mortality in infected people over the age of 85 remains high, despite vaccination and improving treatment options.
“By carrying out SARS-CoV-2 infections of epithelial cells in vitro and studying the responses with single cell sequencing, we get a much more detailed understanding of the viral infection kinetics and see big differences in the innate immune response between cell types,” said co-senior author Dr Kerstin Meyer (Wellcome Sanger Institute).
The team suggest that future research should consider how ageing impacts the body’s response to other viral infections.
Rohit Malhotra is a medical expert and health journalist who offers evidence-based advice on fitness, nutrition, and mental well-being. His articles aim to help readers lead healthier lives.
