Researchers have found that people seriously ill with the Covid-19 disease have antibodies that are blocking so-called interferons, which are an important part of the body´s immune mechanism.
While most people dying from Covid-19 are elderly, up to five to 10 per cent of younger adults and children can also be seriously infected by the SARS-CoV-2 virus, the study, published in the journal Science, reported.
Researchers from all over the world have tried to determine why some people become very ill and others are barely affected by Covid-19.
"Deaths and severe Covid-19 are more frequent among men than women. Our study has shown that men have more of these antibodies," said study author Eystein Husebye from the University of Bergen in Norway.
Husebye was involved in this study because he has had long experience with patients suffering from the immune disease APS1.
APS1 is a serious, but rare, immune disease. Patients with APS1 have a high concentration of antibodies against interferons.
If these patients then become infected with Covid-19, their bodies will work against their own immune systems. In addition, this response has also been seen in patients with milder immune diseases.
"It is relatively easy to see if young people with Covid-19 have these antibodies in their blood. If so, it might be possible to supply them with extra interferons as treatment," Husebye said.
Even if it is easy to use blood tests to discover antibodies against interferons, the author does not recommend massive screening of healthy people.
Most people with APS1 are diagnosed in their childhood, and most people with immune failure have been diagnosed already.
"Immune failure is just a piece in the puzzle when it comes to understanding why young people may die of Covid-19. Old people generally die of more complex causes," the authors wrote.