Moderna Inc could take months to begin shipping a COVID-19 vaccine that works specifically against the Omicron variant, its chief executive officer, Stéphane Bancel, told CNBC on Monday.

The Omicron variant carries a very high global risk of surges, the WHO warned on Monday, as more countries reported cases. 

Bancel told CNBC in an interview that the efficacy of COVID-19 vaccines against the variant was currently not known, and that there should be more clarity in about two weeks.

Moderna said on Friday it was working to advance a booster candidate tailored to the new variant and has also been testing a higher dose of its existing booster and to study other booster candidates designed to protect against multiple variants.

Separately, rivals Pfizer and BioNTech, and Johnson & Johnson have also said they have begun testing their vaccines against the new variant.  

(Reporting by Manas Mishra in Bengaluru; Editing by Sriraj Kalluvila) ((;; within U.S. +1 646 223 8780))