A new strain of the virus that causes COVID-19, known as B.1.1.529, has been labeled the "Omicron variant" by the World Health Organization and classified as a "variant of concern."
This is what we know so far about this new variation on the SARS-CoV-2 virus.
What is the Omicron variant?
The variant known scientifically as B.1.1.529 was little known to the public until November 24, when South African officials reported it to the WHO. It took the organization just two days to elevate its profile and status substantially.
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"This variant has a large number of mutations, some of which are concerning. Preliminary evidence suggests an increased risk of reinfection with this variant, as compared to other" variants of concern, the organization said in a statement Friday.
"(This) variant has been detected at faster rates than previous surges in infection, suggesting that this variant may have a growth advantage."
As of the evening of Nov. 26, the variant has so far been detected in South Africa, Israel, Hong Kong, Belgium and the Netherlands. (Dutch state broadcaster NOS reported that in one sample of passengers from two quarantined flights out of South Africa, nearly 14% tested positive for some version of the coronavirus.)
Media reports indicated that the case in Belgium was an unvaccinated person who had traveled from Egypt -- but one Israeli case was reported to be someone who'd had three doses of vaccine, the last one just two months ago.
What is a Variant of Concern?
The WHO has four levels of classification for COVID variants, in ascending order:
- Variant Being Monitored
- Variant of Interest
- Variant of Concern
- Variant of High Consequence
The CDC defines a variant of concern as: "A variant for which there is evidence of an increase in transmissibility, more severe disease (e.g., increased hospitalizations or deaths), significant reduction in neutralization by antibodies generated during previous infection or vaccination, reduced effectiveness of treatments or vaccines, or diagnostic detection failures."
The Delta variant, for example, which caused a surge in infections in the United States over the summer, was a variant of concern (sometimes called a VOC).
What is the response to the Omicron variant?
Less than 48 hours after the world found out about B.1.1.529, now known as Omicron, most major governments instituted travel bans to and from southern Africa.
The Omicron variant has not been seen in the United States yet, but federal and state authorities say they are actively looking for it.
Both Pfizer and Moderna have said that if in fact the variant is more resistant to their vaccines than past strains, they could develop and ship a modified vaccine within about 100 days.
Mark Levine, the chair of the New York City Council's Health Committee and the incoming Manhattan Borough President, on Friday called for the immediate reimposition of restrictions in the city.
Meanwhile, New York Gov. Kathy Hochul declared a state of emergency and said that while Omicron hasn't been detected in the state yet, "It's coming."