Broadway composer Stephen Sondheim dies aged 91: lawyer to NYT

'High to very high' risk new Covid variant will spread in Europe: EU health agency

WTO conference postponed due to new Covid variant: source

Moderna says it will develop booster shot for new Covid variant

Biden says likely to speak to Russian, Ukrainian leaders

Biden says other nations must donate more Covid vaccines

Canada bans travel from seven African countries over new Covid strain

US imposes travel restrictions on southern African countries

Dutch PM announces new Covid restrictions from Sunday

Dow ends 2.5% lower as new Covid variant causes year's worst drop