Scientists identify 16 genetic factors behind severe Covid symptoms

London: In a major discovery that could aid the development of new treatments for Covid, a team of researchers in the UK has identified genetic factors that make certain people more likely to suffer severe Covid-19 symptoms than others.

The researchers have identified some 16 new genetic variants which include some related to blood clotting, immune response, and intensity of inflammation.

According to Professor Kenneth Baillie, Consultant in Critical Care Medicine at University of Edinburgh, the latest findings point to specific molecular targets in critical Covid-19.

These results explain why some people develop life-threatening Covid-19, while others get no symptoms at all.

The study, published in the journal Nature, showed how a single gene variant that disrupts a key messenger molecule in immune system signalling -- called interferon alpha-10 -- was enough to increase a patient's risk of severe disease.

This highlights the gene's key role in the immune system and suggests that treating patients with interferon -- proteins released by immune cells to defend against viruses -- may help manage disease in the early stages.

The study also found that variations in genes that control the levels of a central component of blood clotting -- known as Factor 8 -- were associated with critical illness in Covid-19.

This may explain some of the clotting abnormalities that are seen in severe cases of Covid-19. Factor 8 is the gene underlying the most common type of haemophilia, the researchers said.

"It is now true to say that we understand the mechanisms of Covid better than the other syndromes we treat in intensive care in normal times -- sepsis, flu, and other forms of critical illness. Covid-19 is showing us the way to tackle those problems in the future," Baillie said.

For the study, the team sequenced the genomes of 7,491 patients from 224 intensive care units in the UK.

Their DNA was compared with 48,400 other people who had not had Covid-19, and that of a further 1,630 people who had experienced mild Covid.

Determining the whole genome sequence for all participants in the study allowed the team to create a precise map and identify genetic variation linked to severity of Covid-19.

The team found key differences in 16 genes in the ICU patients when compared with the DNA of the other groups.

They also confirmed the involvement of seven other genetic variations already associated with severe Covid-19 discovered in earlier studies from the same team.

The findings offer a route to new tests and treatments, to help protect the public from this virus, the team said.