WHO classifies new strain in South Africa as ‘worrisome’

The World Health Organization (WHO) on November 27 named the new strain (B.1.1.529) in South Africa as Omicron, classified as a worrisome variant (VOC).

“This variant has a large number of mutations, one of which is of concern. Preliminary evidence suggests a higher risk of reinfection with this variant than with other strains,” the WHO said.

The number of Omicron infections is increasing steadily in most provinces of South Africa. To date, mutations have been recorded in South Africa, Botswana, Belgium, Hong Kong and Israel.

There is currently no evidence that the strain is contagious, has a high mortality rate, or reduces the effectiveness of the vaccine. But the European Commission still recommends member states limit travel with countries in southern Africa. Some experts fear that Omicron is the reason for the high number of nCoV infections in this area.

According to Tulio de Oliveira, director of the KwaZulu-Natal gene sequencing platform, the new strain has 50 mutations, “some very unusual mutations”. More than 30 mutations are located in the S protein, which helps nCoV attach to human cells.

The receptor-binding region (the part of the virus that first touches the cell) has 10 mutations, much larger than Delta’s two mutations. Omicrons most likely come from an immunocompromised patient who is not able to clear the virus on their own. The same hypothesis has been put forward with the Alpha variant.

The strain also contains two mutations, P681H and N679K, at the furin cleavage site (the site that helps the virus to enter the cell). This is the first time that scientists have recorded these two mutations in a single strain.

People wear masks to prevent Covid-19 in the city of Parys, South Africa, on November 26. Photo: EPA

Still, many epidemiologists have urged calm, noting that several seemingly dangerous strains have emerged and disappeared in recent months.

Sharon Peacock, professor of public health and microbiology at Cambridge University, said: “There are two approaches going forward: wait for more scientific evidence or act now. In my opinion, the best way. especially proactively going ahead of the virus instead of waiting.”

A variant becomes a variant of concern (VOC) when changes in the viral genome are clinically significant or have the following: increased transmissibility; virulence (severity of the disease) increases; change vaccine effectiveness (reduce effectiveness); change diagnostic efficiency (current diagnostic methods are no longer effective)…

Currently, the VOC group includes mutants Alpha, Beta, Gama, Delta. The Variant of Interest (VOI) has Lambda and Mu.

Thuc Linh (Follow CNBC, NY Times)


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