GENEVA, Dec. 4 (CGTN) -- The World Health Organization's (WHO) chief scientist told the Reuters Next conference on Friday that people should not panic over the emergence of the coronavirus variant Omicron and said it was too early to say if vaccines would need to be reworked.

"We need to be prepared and cautious, not panic, because we're in a different situation to a year ago," Soumya Swaminathan said.

Swaminathan said the fast-spreading variant would have to become more transmissible to out-compete the Delta variant, but much remains unknown about the new variant.

Omicron has been detected in at least 38 countries, but no deaths have yet been reported, the WHO said.

The United States and Australia became the latest countries to confirm their first locally transmitted Omicron cases, as the number of Omicron infections from a Christmas party in Norway rose to 17.

The WHO has warned it could take weeks to determine how infectious the variant is, whether it causes more severe illness and how effective current treatments and vaccines are against it.

"We're going to get the answers that everybody out there needs," WHO emergencies director Michael Ryan said.