Gene variations are now being tracked by scientists who believe they offer a route to developing novel therapies that could halt many of the worst COVID-19 symptoms.

Key developments include research which indicates that interferon – a molecular messenger that stimulates immune defences against invading viruses – may play a vital role in defending the body. Scientists have found that rare mutations in some people may leave them unable to make adequate supplies of the interferon they need to trigger effective immune responses to Covid. Trials using interferon as Covid treatments are now under way at several centres.

“These genetic findings give us very clear insights,” said Martin Hibberd, professor of emerging infectious diseases at the London School of Hygiene and Tropical Medicine. “They are natural biological experiments which suggest that people who make more interferon when infected have a better response to the disease. And that in turn tells us that patients could well benefit from treatment with interferon.”

Research is also focusing on a gene known as TYK2. Some variants of this gene are involved in triggering some auto-immune diseases such as rheumatoid arthritis (RA) and also seems to be involved in causing severe Covid. A drug developed to treat RA, baricitinib, has a genetic common denominator with Covid and this has led to it being used in clinical trails against the virus. Last month the pharmaceutical company Eli Lilly announced that early results showed the drug helped Covid patients recover.

“The crucial point is that by understanding the impact of gene variants in the body we can now think about finding drugs that could block their pathways and help patients,” said Jeffrey Barrett, of the Wellcome Sanger Institute’s Covid-19 genomic surveillance programme. “The bad news is that it can take years of experiments to find treatments this way. The good news is that there are now so many scientists working on this kind of thing that we might still some quick answers.”

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