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Irish scientists are among a global group hunting for a genetic explanation as to why some people seem resistant to Covid-19, while others experience life-threatening symptoms. In a landmark paper published recently in Nature Immunology, the consortium set out a strategy for answering one of the pandemic’s greatest questions:
Why do some people not get Covid-19?

The Covid-19 Human Genome Effort, (COVIDHGE; is led by Jean Laurent Casanova of the Rockefeller Institute in New York and Helen Su of the National Institutes of Health in the US. It involves teams from over 50 countries, including one from Trinity College Dublin.

Scientists, over the years, have discovered genetic factors that partly explain why infections such as malaria, HIV, and hepatitis C affect some people more than others. The consortium has already discovered how variations in some immune genes contributes to severe Covid-19 infection.

Now the COVIDHGE consortium wants to find the genes responsible for why some people are resistant to Covid-19. The collaborating COVIDHGE scientists will, over the next 12 months, seek people who seem to be naturally resistant to Covid-19 (having been exposed, in close quarters, and for significant time to an infected person) and compare their genetic and other biological profiles with those of non-resistant people who become infected.

In doing so, they will hunt, in a targeted manner, for genetic answers that could explain why some people are resistant and others not, and by extension, make a global impact in fighting the virus. The Irish group is led by Prof Cliona O’Farrelly, Professor of Comparative Immunology at Trinity College Dublin.

Prof O’Farrelly said: “There is a growing awareness that many people seem to have innate immune-mediated resistance to viral infections. My team and I have been highlighting this for a number of years since our discovery that around one-third of Rhesus-negative Irish women exposed to hepatitis C-contaminated anti-D in 1977-79 did not ever show symptoms of the virus. “Because of that work, and growing information regarding the wildly variable responses that people have to Covid-19 exposure, we are convinced that a proportion of the population is resistant to the virus.