New Zealand has also added nine countries from the region to its high-risk group.
South Africa first identified the variant, because of its virus research expertise, around Johannesburg this month and alerted the WHO. However, it was not known for sure at the weekend where Omicron originated. It has also already turned up in countries as varied as Botswana, Hong Kong, Israel and Belgium. Yesterday it was confirmed to be in Britain.
So far, it's also uncertain how much of a threat Omicron is, although it has dozens of mutations. Other variants like Beta and Lambda haven't been as problematic as Alpha or Delta, for instance. And vaccine shots and boosters have still been able to generally prevent severe disease against the dominant Delta.
Scientists will be trying to find out whether Omicron is more transmissible than Delta, and whether it makes vaccines less effective in limiting spread, hospitalisations and deaths. Epidemiologist Professor Michael Baker said it is highly unlikely a new variant would be able to evade the vaccine entirely.
Pfizer and BioNTech said on Saturday lab data on Omicron is expected within a fortnight and, should specific vaccine changes be required, the process would take about six weeks with about three months for the first of those shots to be shipped.
But the emergence of the variant represents a failure of the overall global response to the coronavirus.
Experts have been warning throughout the pandemic that the world would be vulnerable to variants until countries had even access to vaccines. Africa is still left waiting for more doses, two years on. As a region of low vaccination coverage, it always loomed as an area from where a variant could emerge and spread quickly through travel.
The Government here will be considering whether any of the country's responses have to be tweaked further. The Ministry of Health's initial statement said: "This particular strain is in its infancy and ... we are closely watching and monitoring evidence and countries' responses ... We remain in a good position to minimise the impact of any new variants with isolation and routine testing of international arrivals."
New Zealand's border reopening plans for early next year are hopefully still on course, but we will have to wait and see after this warning bell. It is clearer that the process shouldn't be rushed.
As is the case with Delta, protection measures such as quarantine where necessary, mask-wearing, social distancing and hybrid work options have to be kept in the tool box to back up vaccines. The doses can't do all the work themselves, but people who still haven't been vaccinated should do. Boosters should be booked for those eligible.
Unlike Europe, in the grip of a winter Delta surge mainly hitting the unvaccinated, New Zealand is experiencing hot weather and still currently has its isolation, borders, testing system and good rates of vaccination.
But we don't want to become experts in the entire Greek alphabet.
