FAQ: WHO Declares 'Omicron' a Variant of Concern. What Do We Know So Far?
The World Health Organisation (WHO) on Friday declared the new variant emerging from South Africa B.1.1.529, a 'Variant of Concern' (VOC). This classification means the WHO sees it a threat of global public health significance. The agency said that the preliminary evidence suggests an increased risk of reinfection with this variant dubbed as Omicron. The WHO assigns a Greek letter to these variants - to prevent stigmatising the place of origin where the the virus was first detected.
So far we've had Alpha that was first documented in the UK, Beta - that originated in South Africa, Gamma - that was first seen in Brazil and Delta - that was first documented in India in October 2020.
Currently Delta is the predominant variant circulating among the population.
What did the WHO say about Omicron?
South Africa has had three distinct peaks since the beginning of the pandemic. The second peak was dominated by the Delta variant.
The WHO says they found the variant to have a large number of mutations, some of which are concerning.
They also said that the preliminary evidence suggests an increased risk of reinfection with this variant, as compared to other VOCs.
The variant was first reported on 24 November by South African scientists, but it is believed to have been in circulation for a few weeks atleast. Almost all provinces of South Africa are now reporting cases of this variant.
Where is the origin of Omicron?
Scientists in South Africa linked the surge in case numbers in the Gauteng province, a densely populated urban area that includes Pretoria and Johannesburg, to this variant in the last two weeks.
But the variant was first detected in Botswana on November 11.
Two cases were also reported from Hong Kong, these were travellers from South Africa.
Israel reported a case on Thursday evening and Belgium reported a case in someone who had a travel history to Turkey and Egypt.
How did this mutation emerge?
The constellation of 32 mutations seen in Omicron, almost double of Delta, seem to suggest the variant emerged in an immunocompromised person with a possibly untreated chronic infection.
Why are these mutations concerning?
The unusual constellation of mutations are on the spike protein of the virus. The virus uses this spike protein to enter the human cell. Scientists worry that the antibodies that previous infection or vaccination made in the human body won't be able to fight it - basically it will possibly have immune evading properties.
WHO says it is early days and scientists are examining the data gathered so far to better understand how the virus will impact reinfections and vaccines.
Do we know if the virus is more transmissible?
It's early days but the speed with which the variant has spread has scientists worried. South Africa had only 273 cases on 16 November and that went up to 1200 by this week. A large percentage was from the Gauteng province where the variant has become a dominant strain.
Will Omicron evade COVID-19 vaccines currently in use?
Scientists worry that while the vaccines will still recognise the variant, it may provide less protection. Data from real world studies, reinfections etc will have to be studied before coming to this conclusion.
Pfizer has already declared it will be able to tweak its vaccine in 100 days if needed.
Will the current PCR tests be able to pick the variant?
Yes, infact the scientists in South Africa used the RTPCR test to detect the new variant at a faster pace, since genome sequencing takes time.
Of the 29 genes found in the coronavirus, the RTPCR test looks for 2-3 genes including the spike gene and the nucleocapsid gene. Omicron, due to its mutations, does not test positive for the spike gene, making it easier to separate it from other variants. Scientists looked at samples that tested positive for nucleocapsid but negative for spike gene.
All RT PCR tests available in India target these genes.
Will Omicron cause more severe disease?
It's too early to say. Scientists in South Africa are closely monitoring the health of those who have tested positive for Omicron, but it is early days as severe disease sets in a couple of weeks later.
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