OMICRON, a new SARS-CoV-2 strain, first detected in the Gauteng province of South Africa, has been acknowledged by WHO as a “variant of concern”. Already, cases have been reported from other countries, making clear that Omicron is unlikely to be contained geographically. If it outperforms Delta in creating new infections, it may then replace Delta as the dominant variant in Covid-19 infections, as Delta has done to the earlier variants.