What We Know: Professor Weighs in on New Omicron Variant of Coronavirus

Biology Professor Dave Wessner studied the pathogenesis of coronaviruses as a post-doctoral researcher at the Uniformed Services University of the Health Sciences and shares his insight on the variant.

Do we have a feel for how quickly the SARS-CoV-2 virus is mutating, relative to other viruses?

Although we continue to hear a lot about the emergence of new SARS-CoV-2 variants, coronaviruses actually mutate less frequently than other viruses that have an RNA genome, like influenza viruses. Relative to humans, coronaviruses mutate rapidly, but relative to other viruses, their mutation rate is low. To a large extent, this is because coronaviruses contain a proof-reading enzyme. They have the ability to correct some of the errors that normally occur during replication. Nonetheless, mutations do occur, and if the mutations confer a selective advantage, then variants containing that mutation will proliferate.

Why are the mutations on the spike protein so worrisome?

The most concerning aspect of this variant is the large number of mutations in the spike protein. The spike protein is of interest for two reasons. First, the spike protein allows the virus to attach to our cells and initiate an infection. Second, the spike protein is the target of our immune system and the basis for all the available vaccines. Significant changes in the spike protein could allow the virus to bind to and infect our cells more easily. Changes like this could lead to increased transmission. Significant changes in the spike protein also could result in decreased effectiveness of the vaccines. If the shape of the spike protein changes, then the immune response we develop because of the vaccine may not effectively recognize this new version of the virus.

It sounds like the Omicron variant has a larger number of mutations than previous variants. Is that a significant development?

The number of mutations in this variant is striking. Rather than a small step change from previously identified variants, it seems to be a big leap. There is some speculation that this variant may have evolved within an immunocompromised person, like someone who has HIV. In an immunocompromised person, the virus could replicate and mutate with little interference from the host’s immune system. Within that person, then, the virus could evolve. That’s been a concern since the very early days of the pandemic.

When will we know what kind of threat this poses?

The concerns about increased transmission and reduced vaccine effectiveness have not been confirmed. At this point, they still are theoretical concerns. There is evidence that cases have increased significantly over the past few weeks in the region where this variant was first identified. That correlation suggests something may be going on, but it’s not good proof. I imagine we’ll find out more over the next couple weeks.