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How do mutations in these variants change the virus's ability to infect people?

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SciLine tracks common science questions that reporters have about the coronavirus pandemic – and reaches out to our network of scientific experts for quotable comments in response. Reporters can use the comments below in news stories, with attribution to the scientist who made them

This article was published on
January 19, 2021

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Expert Comments: 

Thomas Friedrich, PhD

The scientific community is still studying the mechanisms by which specific mutations alter the virus’s ability to infect people. Most work is focused on changes to the amino acids that make up the viral Spike (S) protein, which is responsible for attaching the virus to cells so that it can enter and infect them. It seems likely that some changes to the structure of Spike could allow it to attach more efficiently to human cells, which could lead to greater transmissibility. Some mutations may also change the structure of the Spike protein in a way that makes it more difficult for antibodies to attach to it. This would help ‘hide’ the virus from the immune response. It is less clear whether mutations in the current variants of concern specifically alter antibody recognition to a meaningful degree.

Kartik Chandran, PhD

Current evidence suggests that mutations in B.1.1.7 allow increased viral replication—and larger viral loads—in the upper respiratory tract of infected persons. This likely accounts for the increased transmissibility, at least in part.

Scott C. Weaver, PhD

So far, one mutation, D614G, that occurred early last year quickly became the predominant strain worldwide. It allows the virus to replicate more efficiently in the upper airway to enhance shedding and the efficiency of transmission. Fortunately, this substitution does not render the virus resistant to the antibodies generated in vaccinated persons. Likewise, another substitution in the spike, N501Y, which is shared by both the UK and S. African variants, does not allow the virus to escape neutralizing antibodies produced in response to vaccination.

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