The SARS-COv-2 virus began mutating to avoid human immunity in the spring last year – raising concerns about the durability of the current vaccines, according to the findings of a major UK scientific study.
The researchers in Scotland have been studying the N439K variant, which was driven to extinction by the first, extreme lockdown last year.
The research has highlighted the “plasticity” of the receptor binding domain in the virus spike protein, the researchers warn, and, while the mutation they studied disappeared, similar mutations underlie the new variants now wreaking havoc in the latest wave of the pandemic.
The researchers began work last June after the mutation was found in Scotland.
Linking the mutation to studies of patients, they found no increase in disease severity or virulence – but they found the virus could mutate to avoid human immunity.
Professor Emma Thomson, from Glasgow University, said: “We were concerned about this mutation in 2020 because it was predicted to increase binding to the human ACE2 receptor and we were worried that it might be associated with escape from natural immunity. So, we were initially relieved when it disappeared after the first lockdown.
“However, it became clear the virus could mutate to avoid the immune response without losing fitness to replicate – we were able to demonstrate this in our high biocontainment laboratories through cross-competition assays at the Centre for Virus Research.”
She added: “The plasticity of the receptor binding motif in the spike protein of SARS-CoV-2 and the evidence that a single mutation, N439K can impair neutralizing antibody responses indicates that we may need to update vaccine design in the future, particularly in the light of the emergence of new variants around the world.”
Fellow researcher Prof David Robertson said: “Our results here on the plasticity of the RBM predicted the emergence of many of the changes present in the SARS-CoV-2 variants of concern. Collectively these data indicate the importance of rolling out the vaccine to as many people as is possible as quickly as possible in the coming months and of genome surveillance efforts to monitor for novel variants with new antigenic properties.
“There is no evidence to indicate the vaccine won’t remain effective in the short to medium term but what is happening is the circulating SARS-CoV-2 are moving away from the early variants that were used in the first vaccine preparations.”
He added: “The need for vaccine re-design is looking inevitable, particularly as the vaccine coverage is going to be very unevenly distributed. We urgently need a more equitable use of vaccines internationally with scale up in production and dissemination. Controlling this virus is possible but it needs a more coordinated global effort.”
* A single dose COVID-19 vaccine has been found to be 66% effective in preventing viral infection, it has been announced.
The Janssen phase 3 data was published on Friday. The company says it is also testing the benefits of a second dose.
Circulating SARS-CoV-2 spike N439K variants maintain fitness while evading antibody-mediated immunity Cell 28 January 2021
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