COVID-19 is not gone yet. In fact, as the Northern hemisphere is coming closer to autumn, it is expected that COVID-19 statistics will get significantly worse. However, up until now children were more resilient to COVID-19 and it is interesting to see why.
Scientists at the University of Queensland found that lining in children’s noses is actually a better protective layer against COVID-19 than what adults have.
SARS-CoV-2 virus is less dangerous to children. Image credit: NIAID via Wikimedia (CC BY 2.0)
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We’ve been dealing with COVID-19 since the end of 2019 and over all these months we learned many valuable lessons. For example, COVID-19 is more dangerous to the elderly (higher risk of death from COVID) while children seem to be more immune and face less severe symptoms. Children catch COVID-19 much more rarely and when they do it is usually not a big deal – symptoms they suffer from seem to be mild (in most cases at least).
Of course, this seems to be due to children’s more resilient immune system. However, the first line of defence – the lining in airways – is also very important. Now Australian scientists exposed the samples of nasal lining cells from 23 healthy children and 15 healthy adults to SARS-CoV-2 – virus that causes COVID-19 disease. This experiment revealed that the virus is not able to replicate as efficiently in the children’s nasal cells as it does in adult noses. Furthermore, children’s nasal mucus seems to have a stronger antiviral response. Scientists have several ideas why that might be the case.
Dr Kirsty Short, one of the authors of the study, said: “It could be an adaptation to the increased threats of ‘foreign invaders’ such as viruses or bacteria observed in childhood. It’s also possible that increased exposure to these threats in childhood ‘trains’ the nasal lining in children to mount a stronger pro-inflammatory response. Or alternatively, metabolic differences between children and adults could alter how virus-fighting genes express themselves.”
Even the Delta variant, which spreads very easily, is less likely to replicate in the nasal cells of children compared to adults. On the other hand, this effect was not as visible in Omicron. Children can get sick and appropriate protection measures should be taken, but their noses seem to be able to fight off SARS-CoV-2 better. However, scientists still warn against getting too comfortable with life in COVID-19 times – all of this might change very quickly as new variants of this virus emerge.
No one knows when COVID-19 will go away permanently. For now we need to understand how it works, what protections our bodies can mount and how we can neutralise future waves of it. If we understood how children protect themselves against COVID-19, maybe we could borrow some of those capabilities for adults as well.
Source: University of Queensland