The case for updating covid-19 vaccines for the Omicron variant

VARIANTS VARY, but how much? Since SARS-CoV-2 was first sequenced at the beginning of 2020 dozens of strains have been identified. And five have been designated “variants of concern” by the World Health Organisation (WHO). The latest of these is Omicron, which was given its name in November last year. As Omicron becomes dominant around the world, working out how to protect people from it is becoming more pressing. To do this, scientists must study how different this strain is from those that came before and what that means for immunity, from both previous infection and vaccination.