What we know about the new coronavirus variant omicron
World Health Organization declares B.1.1.529 a variant of concern
Authorities around the world have reacted with alarm to the recently discovered coronavirus variant B.1.1.529 that the World Health Organization labelled a variant of concern and named omicron Friday.
Canada, the U.S., Britain, the European Union and India are among those announcing stricter border controls as scientists carry out tests to determine if the variant is more transmissible or infectious than others, as well as if it is resistant to vaccines.
At least a dozen countries have confirmed cases of the variant as of Monday, including Canada.
Where and when was the new variant found?
South African scientists doing genomic sequencing detected the new variant on Tuesday in samples from Nov. 14-16.
On Wednesday, South African scientists sequenced more genomes, informed the government that they were concerned and asked the World Health Organization (WHO) to convene its technical working group on virus evolution Friday.
The country has identified around 100 cases of the variant, mostly from its most populated province, Gauteng, where Johannesburg and Pretoria are located.
What is meant by variant of concern?
WHO said on Friday its advisers recommended that the variant be designated one of concern, its most serious level.
The Technical Advisory Group on SARS-CoV-2 Virus Evolution met today to review what is known about the <a href="https://twitter.com/hashtag/COVID19?src=hash&ref_src=twsrc%5Etfw">#COVID19</a> variant B.1.1.529.<br>They advised WHO that it should be designated a Variant of Concern.<br>WHO has named it Omicron, in line with naming protocols <a href="https://t.co/bSbVas9yds">https://t.co/bSbVas9yds</a> <a href="https://t.co/Gev1zIt1Ek">pic.twitter.com/Gev1zIt1Ek</a>—@WHO
The latter label is applied if there is evidence that it is more contagious or more virulent or vaccines work less well against it, or has a combination of those characteristics, the UN agency's website says.
Why is it worrying scientists?
All viruses — including SARS-CoV-2, the virus that causes COVID-19 — change over time. Most changes have little or no impact on their properties.
However, some changes may affect how easily they spread, their severity or the performance of vaccines against them.
This variant has drawn scrutiny because it has more than 30 mutations of the spike protein that viruses use to get into human cells, U.K. health officials say.
That is about double the number of delta, and makes this variant substantially different from the original coronavirus that current COVID vaccines were designed to counteract.
South African scientists say some of the mutations are associated with resistance to neutralizing antibodies and enhanced transmissibility, but others are not well understood, so its full significance is not yet clear.
U.K. Health Security Agency Chief Medical Adviser Dr. Susan Hopkins told BBC radio some mutations had not been seen before, so it was not known how they would interact with the other ones, making it the most complex variant seen so far.
In an update on Sunday, WHO confirmed that studies are currently underway to confirm if it is more transmissible, if it causes more severe disease or if it can evade vaccines.
WHO says it will take "days to several weeks" before we get definitive data on the variant and, in the meantime, vaccines remain a critical tool to contain the virus.
Although preliminary data suggests there are increasing rates of hospitalization in South Africa, WHO said it may be due to increasing overall numbers of people becoming infected, rather than a result of specific infection with omicron.
No unusual symptoms have been reported following infection with the B.1.1.529 variant and, as with other variants, some individuals are asymptomatic, South Africa's National Institute for Communicable Diseases (NICD) said.
What about reinfection?
WHO says preliminary evidence suggests there's an increased risk of reinfection with omicron, compared to other variants of concern.
That means people who previously had COVID-19 could become reinfected more easily with omicron.
Where else has it been identified?
South African scientists say early signs from diagnostic laboratories suggest it has spread rapidly in Gauteng and may already be present in the country's other eight provinces.
The country's daily infection rate nearly doubled on Thursday to 2,465. NICD did not attribute the resurgence to the new variant, though local scientists suspect it is the cause.
As of Monday, the open database of coronavirus variants from the global initiative on sharing all influenza data (GISAID) has registered 165 cases of B.1.1.529 in total. Cases of the variant have been registered in countries including South Africa, Botswana, the Netherlands, Australia, the United Kingdom, Hong Kong, Canada, China, Italy, Germany, Belgium and Israel.
Scientists say early detection due to genomic surveillance in Botswana and South Africa may have limited the spread of the variant.
The variant is relatively easy to distinguish in PCR tests from delta, the dominant COVID-19 variant and the most infectious so far. Unlike delta, it has a mutation known as the S-gene drop-out.
However, this is not a unique identifier because the Alpha variant, first identified in Britain, also has that mutation.
How has Canada responded?
Before the cases were confirmed in Canada, government officials moved to limit travel from southern Africa in response to concerns over the variant.
Health Minister Jean-Yves Duclos announced several measures on Friday, including barring all foreign nationals who have travelled through any of seven countries in southern Africa — South Africa, Namibia, Zimbabwe, Botswana, Lesotho and Eswatini or Mozambique — in the last 14 days from entering Canada.
Canadian citizens and permanent residents will be allowed to return home from these countries, but they will be required to take a COVID-19 test upon arrival and wait for the results at a hotel.
If the test is negative, those returning travellers will be released to quarantine for a mandatory 14 days at home. They will also be required to go through a so-called "day eight" test on the eighth day of quarantine.
With files from CBC News