Covid-19 | SARS-CoV-2 variant B.1.1.529 a ‘Variant of Concern’: WHO

Our Bureau | | | Updated on: Nov 27, 2021
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Now named Omicron, Countries asked to up surveillance and enhance genome sequencing

The new SARS-CoV-2 variant, B.1.1.529 has been classified as a “Variant of Concern” and is named Omicron, the World Health Organization has said.

“Based on the evidence presented indicative of a detrimental change in COVID-19 epidemiology, the TAG-VE has advised WHO that this variant should be designated as a VOC, and the WHO has designated B.1.1.529 as a VOC, named Omicron,” a note from WHO said.

The Technical Advisory Group on SARS-CoV-2 Virus Evolution (TAG-VE) is an independent group of experts that periodically monitors and evaluates the evolution of SARS-CoV-2 and assesses if specific mutations and combinations of mutations alter the behaviour of the virus. The TAG-VE was convened on Friday to assess B.1.1.529.

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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 VOCs. The number of cases of this variant appears to be increasing in almost all provinces in South Africa,” it said, echoing observations made by pubic health voices the worldover.

“Current SARS-CoV-2 PCR diagnostics continue to detect this variant. Several labs have indicated that for one widely used PCR test, one of the three target genes is not detected (called S gene dropout or S gene target failure) and this test can therefore be used as marker for this variant, pending sequencing confirmation. Using this approach, this variant has been detected at faster rates thanprevious surges in infection, suggesting that this variant may have a growth advantage,” the WHO explained.

A Variant of Concern (VOC) is defined as a variant that meets one or more of the following changes, “increase in transmissibility or detrimental change in Covid-19 epidemiology; OR increase in virulence or change in clinical disease presentation; OR decrease in effectiveness of public health and social measures or available diagnostics, vaccines, therapeutics.” the WHO said.

First reports

The B.1.1.529 variant was first reported to WHO from South Africa on 24 November 2021. “The epidemiological situation in South Africa has been characterised by three distinct peaks in reported cases, the latest of which was predominantly the Delta variant. In recent weeks, infections have increased steeply,coinciding with the detection of B.1.1.529 variant. The first known confirmed B.1.1.529 infection was from a specimen collected on 9 November 2021,” the WHO said.

There are a number of studies underway and the TAG-VE will continue to evaluate this variant.

Advisory to countries

Countries have been urged to enhance surveillance and sequencing efforts to better understand circulating SARS-CoV-2 variants. They also need to submit complete genome sequences and associated metadata to a publicly available database, such as GISAID. They need to report initial cases/clusters associated with VOC infection to WHO through the IHR mechanism. And where capacity exists and in coordination with the international community, perform field investigations and laboratory assessments to improve understanding of the potential impacts of the VOC on Covid-19 epidemiology, severity, effectiveness of public health and social measures, diagnostic methods, immune responses, antibody neutralization, or other relevant characteristics.

Finally, it pointed to the need for public health measures to reduce the risk of Covid-19, including wearing well-fitting masks, hand hygiene, physical distancing, improving ventilation of indoor spaces, avoiding crowded spaces, and getting vaccinated.

Published on November 27, 2021

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