British scientists have identified some of the genetic factors that make certain people more likely to suffer severe Covid-19 symptoms than others, as part of a major study that could aid the development of new treatments for the disease.
Researchers pinpointed 16 genes that predispose patients to critical illness as part of the world’s largest study into the genetics of the disease, which was led by scientists from the University of Edinburgh and Genomics England. They also confirmed seven other genes associated with severe Covid that had been identified by earlier research.
The genes pinpointed by the research are linked to the immune system’s ability to recognise foreign pathogens, alongside the biological mechanisms involved in blood clotting and lung inflammation — some of the hallmarks of severe Covid. The disease has killed an estimated 6mn people since the World Health Organization declared the coronavirus outbreak a global pandemic in March 2020.
Dr Kenneth Baillie, a critical care consultant from the University of Edinburgh who led the study, said the results helped “explain why some people develop life-threatening Covid-19, while others get no symptoms at all”.
“More importantly, this gives us a deep understanding of the process of [the] disease and is a big step forward in finding more effective treatments,” he said. Potential new treatments could help “get the mortality down to zero” among Covid-19 patients admitted to intensive care, he added.
The research identified genetic patterns by comparing whole genome samples from 7,491 Covid-19 patients admitted to intensive care units across the UK with the DNA of 1,630 people who experienced mild Covid-19 symptoms and a further 48,400 people who have never had Covid-19 and had their DNA analysed as part of the UK government’s 100,000 Genomes Project.
The UK leads the world in genomic sequencing on account of substantial government investment over the past decade. Whole genome sequencing — a process which involves reading all 3bn biochemical letters of an individual’s genetic code — is a more labour-intensive version of the process used to analyse viral variants of Covid-19.
Scientists said they hoped the genetic clues offered by the findings, published in the scientific journal Nature on Monday, could help medical experts to identify existing drugs that could be repurposed to treat Covid-19 or contribute to research for novel treatments.
Existing drugs used to treat illnesses such as asthma and chronic obstructive pulmonary disease already target some of the 16 genes identified by the study and could now be selected for clinical trials, the researchers said.
Earlier results from the same study helped to identify arthritis drug baricitinib, which research published last week found cut the mortality risk of Covid-19 by 13 per cent, as a potential treatment for the virus.
Sir Mark Caulfield, formerly chief scientist at Genomics England and a co-author of the study, said the findings would “offer a route” to new tests as well as treatments. “As Covid-19 evolves, we need to focus on reducing the number of people getting seriously ill and being hospitalised,” he added.
Baillie suggested that the research could help clinicians better understand severe illness caused by other viral infections in future. “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,” he said. “Covid-19 is showing us the way to tackle those problems in the future.”