Firms give vaccine reassurance for Omicron; WHO advises against travel bans

News of Omicron's emergence wiped roughly $2 trillion off global stocks on Friday, after it was first identified in southern Africa and announced on Nov. 25.

The World Health Organization warned countries on Tuesday not to impose blanket travel bans over the new Omicron coronavirus variant as governments and scientists try to determine how much protection current vaccines would offer against the strain.

Financial markets fell sharply after the head of drugmaker Moderna said existing COVID-19 vaccines would be less effective against the Omicron variant. MSCI's gauge of stocks across the globe shed 1.39% a day after broad declines in Europe and Asia.

BioNTech's chief executive struck a cautiously positive note, saying the vaccine it makes in a partnership with Pfizer would likely offer strong protection against severe