Scientists are tracking small differences in DNA to explain why the disease has different effects. An anonymous reader shares a report from The Guardian: Key developments include research which indicates that interferon -- a molecular messenger that stimulates immune defenses 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 centers. 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. Other research -- pioneered by Kenneth Baillie, of Edinburgh University, and outlined in a recent issue of Science -- has uncovered several other genes that appear to be important. These include OAS genes that are triggered by interferon and which code for proteins that are involved in breaking down viral RNA, from which the Covid-19 virus is made. Baillie's research has yet to be peer reviewed and he has counseled caution in interpreting this work. Nevertheless, he told Science that he hoped his results would speed the development of treatments "because the epidemic is progressing at such an alarming rate, even a few months of time saved will save lots of lives". In addition, other researchers point out that there are other ways of using genetics to combat Covid. Dr Dipender Gill of Imperial College London has, with colleagues, used genetic data to predict how different interventions could affect disease reactions. To do that, Gill -- working with a team of British, Norwegian and American scientists -- analyzed data from thousands of patients, using genetic variants that increase individuals' risk of acquiring these conditions. They were then able to carry out studies that would show if action taken to modify these traits would reduce susceptibility to severe Covid-19. The team made two key discoveries. "We found there is a causal link between obesity and the risk of having a severe Covid-19 [reaction]. We also found the same effect for smoking. This indicates that losing weight and giving up smoking will have a direct impact in improving your chances of surviving Covid-19. That is the power of genetic studies like these."

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