In COVID Battle, Omicron May Outrun Delta, Experts Say

Brenda Goodman, MA

December 03, 2021

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

The genetic changes found in the new Omicron variant indicate it could be passed more easily from person to person than Delta, according to the latest threat assessment from the United Kingdom's Health Security Agency, which has done some of the best and fastest characterization of coronavirus variants in the world.

Another new report, from the Network for Genomic Surveillance in South Africa, supports that assessment. It shows that Omicron has quickly outpaced Delta in South Africa.

In October, 80% of all coronavirus samples sequenced in South Africa were from the Delta lineage. Omicron wasn't even part of the mix. In November, 75% of sequenced viruses have been Omicron, with 22% Delta.

In the new UK report, scientists write that Omicron's mutations appear to help the virus replicate more quickly in the body and may help it bind more tightly to the ACE2 receptor on human cells.

"Structural modelling suggests that the mutations present may increase human ACE2 binding affinity to a much greater extent than that seen for any other variant," the report states.

Studies of Omicron's genetic relationship to other variants suggests that it recently emerged in humans.

Based on structural modeling of the viral genetic changes, the report states the virus has mutations that change the shape of all four of the sites where neutralizing antibodies lock onto it, making it likely that it can evade natural immunity.

Indeed, early research from South Africa suggests that people who have already been infected with the coronavirus may be getting infected again with Omicron.

Based on the same structural modeling, it's highly likely that Omicron has escaped at least some of the protection people get from COVID-19 vaccines, although laboratory testing and epidemiological studies are needed before we can know that for sure.

The modeling also suggests that monoclonal antibodies may not work as well against this variant, but lab tests are needed for clarity on this point, too.

Sources

UK Health Security Agency, Risk Assessment for SARS-CoV2 Variant: Omicron, Dec. 3, 2021

Network for Genomic Surveillance in South Africa: "SARS-CoV-2 Sequencing Update 3 December 2021."

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