Scientists have discovered why some coronaviruses are more likely to cause severe disease, which has remained a mystery until now. Researchers of the University of Bristol-led study, published in Science Advances today (November 23), say their findings could lead to the development of a pan-coronavirus treatment to defeat all coronaviruses—from the 2002 SARS-CoV outbreak to omicron, the current variant of SARS-CoV-2, as well as dangerous variants that may emerge in future.