It will take a number of weeks to fully understand the new Omicron variant, says the World Health Organisation.
Margaret Harris from the WHO says there needs to be more vaccine equity globally to stop future variants emerging.
"I think the critical thing is that all countries that have got access to vaccines - also countries that have the pressure or the power to influence the manufacturers to increase the manufacturing in the countries with no access - that's got to happen really rapidly.
"Also, sharing of doses really has to happen much more rapidly.
"We need to get every country vaccinated - let's hope this is a dress rehearsal, let's hope this is not the big one.
"But the big one will come if we don't deal with vaccine equity properly and seriously".
Margaret Harris also said there needs to be more time to allow scientists to evaluate data on the Omicron variant.
"To be honest, we've got more questions than answers - but the reason for putting this on the list of Variants of Concern was two things.
"The unprecedented number of mutations - especially affecting the spike region, which is the thing the virus uses to get into our cells.
"And the other thing - some emerging evidence that people were getting re-infected with the Omicron, people who'd been infected with something else.
"But the big issues we want to understand is what's it's ability to transmit itself, and will it have any ability to escape the vaccine".
