China Variants and Omicron XE Put Fresh Focus on Covid Mutations

The disclosure of new Covid variants emerging in China and the rise of a potentially more transmissible strain in the U.K. has recast the spotlight on the ongoing risk of the virus, even as health experts say there’s no reason to panic.

The World Health Organization said a hybrid of two omicron strains -- BA.1 and BA.2 -- that was first detected in the U.K. and dubbed XE could be the most transmissible variant yet. It is estimated to spread 10% more easily than BA.2, which itself was more transmissible than the original omicron famous for its ease of penetration. ...