Status: 08/18/2021 3:57 p.m.
Children are just as infected with the coronavirus as adults, but have to struggle much less often with severe courses. Scientists have now possibly found a reason for this: It could be due to the immune system of the upper respiratory tract.
From the beginning of the pandemic it became clear that children are usually much better at coping with an infection with the coronavirus than adults, and they are far less likely to get seriously ill with Covid-19. While previously ill people and the elderly sometimes have to fight for their lives, children often do not even have symptoms.
This phenomenon has long puzzled scientists – now a research team has found a possible reason for this: According to this, the immune system in children in the upper respiratory tract is significantly more active than in older people and is therefore probably better equipped to fight off the virus. The “Spiegel” reported about it first.
Children’s immune systems “on constant alert”
Children are currently coming back into focus, because at least everyone under the age of twelve can still not be protected by a vaccination – but at the same time school is starting again or has already started in more and more federal states. “We wanted to understand why the virus defense apparently works so much better in children than in adults,” explains Professor Irina Lehmann, head of the Molecular Epidemiology Group at the BIH.
And so the team collected samples from the nasal mucosa of healthy and SARS-CoV-2 infected children and adults and examined the course of the disease. The comparison of the cells obtained from the 42 healthy and infected children as well as 44 adults showed a surprising result: the defense cells of the nasal mucosa of healthy children are more or less constantly on high alert – even without an acute infection. As a result, they apparently often manage to fight off SARS-CoV-2 before it can penetrate the deeper airways.
In order to be able to fight viruses quickly, so-called pattern recognition receptors have to be activated, explain the researchers. Exactly this system was more active in the cells of the upper respiratory tract and in certain cells of the immune system in the children than in the adults, the analyzes showed. If a virus infects the cell, the body produces the messenger substance interferon, which initiates the fight against the virus. In adults, the early warning system is taken by surprise, the virus is not combated as effectively and can spread more widely.
Findings for treatment of adults
According to co-author Irina Lehmann, the researchers’ findings could play a role in the future of the pandemic: “We have learned from this study that there are obviously not only risk factors for severe COVID-19 courses, but also protective factors.” One can now think about the extent to which such an immune response can be triggered in a targeted manner before an infection – in order to “possibly protect risk patients from a serious illness”. According to the researchers, this can happen in the form of a nasal spray – but it is still “a long way off”.
The team of researchers from the Berlin Institute of Health in the Charité (BIH), the Charité-Universitätsmedizin Berlin, the University Hospital in Leipzig and the German Cancer Research Center (DKFZ) in Heidelberg presented its results in Nature Biotechnology journal released.