The World Health Organization (WHO) said on Monday the Omicron coronavirus variant carried a very high risk of infection surges, while border closures by more countries cast a shadow over an economic recovery from the two-year pandemic.

Big airlines acted swiftly to protect their hubs by curbing passenger travel from southern Africa, where the new Omicron variant was first detected, fearing that a spread of the variant would trigger restrictions from other destinations beyond the immediately affected regions...