Omicron causes a less severe illness than earlier variants

WITH ITS ability to escape immunity induced by past infections and vaccines, the Omicron variant of SARS-CoV-2, first detected in South Africa on November 9th, has been tearing around the world, causing record numbers of cases of covid-19 as it does so. Australia, Britain, Denmark, France, Italy and South Africa are at the forefront of this rising wave of infections. But Omicron has reached at least 113 other countries, too.

Yet despite its ominous-looking clutch of mutations, particularly in the “spike” protein it uses to attach itself to cells when infecting them, the past week has given grounds for hope that the symptoms Omicron causes are less severe than those induced by its predecessors, and that people who do get infected are thus less likely to end up in hospital, or dead. This good news is tempered by the fact that it is far more contagious than those predecessors. It will thus spread widely in coming weeks. And a higher infection rate, even of a less serious illness, could still overwhelm hospitals and cause many deaths.