Covid ‘much more severe in elderly than for children’
Older adults are far more likely to develop severe Covid than children, because the cells in their nostrils are nowhere near as good at fighting off the virus, a study suggests.
Three days after infection, those aged over 70 have almost 1,000 times as many virus particles in their noses as do children, with younger adults somewhere in between.
The nose is the virus’s gateway to the body, playing a key role in how serious the infection will be by governing how far it will spread and in what quantities.
Now, a study finds that children’s nasal epithelial cells (NECs) are far better at shutting down the replication and spread of the virus than those of older people, providing an explanation for why children typically have much milder Covid symptoms.
Although not technically immune cells, these NECs “contribute to the immune response and help direct where immune cells go and behave”, the researchers said.
“Our research reveals how the cells we have in our nose changes with age, and how this affects our ability to combat a Covid infection,” said Claire Smith, of University College London.
“We were surprised the age groups had such different responses. We had thought that the children’s response may be weaker or absent in the elderly, but we were not expecting a completely different response facilitated by different cell types,” Dr Smith said.
“This could be crucial in developing effective anti-viral treatments tailored to different age groups, especially for the elderly who are at higher risk.
“The most effective anti-viral therapies will most likely result from combinations of drugs – those that target the virus and those that help the host to clear the infection. Our data reveal new ways we could help the host to control infection that could be crucial in developing effective therapy in older adults.”
Dr Smith said there are other reasons why older people have more severe symptoms.
Professor Lawrence Young, a virologist at Warwick University who was not involved in the research, said: “This is a very interesting study which provides important insights into the responses of nasal cells to infection with Covid.”