The omicron variant of the coronavirus is more likely than the delta variant to escape the protection built by vaccines or a previous infection, Japanese scientists have reported.

A team of researchers headed by Hiroshi Nishiura, a Kyoto University professor, also told the health ministry’s advisory board Wednesday that omicron’s effective reproduction number, or the average number of people who contract the variant from one infected person, was significantly higher than that of the delta variant.

Its findings were reportedly based on an analysis of data amounting to about 200 cases confirmed in South Africa, where the omicron variant was first detected, from late September to November.