July 2, 2020

expert reaction to paper tracking mutations in the SARS-CoV-2 virus with possible implications for infectiousness

A study, published in Cell, looked at mutations in the SARS-CoV-2 virus with possible implications for infectiousness.

Dr Erik Volz, Imperial College London and member of the COG-UK Consortium, said:

“Whilst modelling and experiments in the laboratory are useful, the most important thing is what happens in a human population.

“Our recent analysis of more than 30,000 viral genomes in the UK shows that while this mutation in the SARS-CoV-2 Spike protein may possibly increase the rate of transmission between people, the difference we see is much less than the difference in cell infectivity measured in the laboratory.  Reassuringly, we also see no apparent effect on disease severity.

“COVID-19 Genomics UK (COG-UK) Consortium website: https://www.cogconsortium.uk/

“Report 9 (includes findings on D614G variant in spike protein): https://www.cogconsortium.uk/wp-content/uploads/2020/07/25th-June-2020-Report-COVID-19-Genomics-UK-COG-UK-Consortium.pdf

“Report 9 explainer: https://www.cogconsortium.uk/news/commentary-cog-uk-report-9-25th-june-2020/

“All data reports: https://www.cogconsortium.uk/news/“

Dr Simon Clarke, Associate Professor in Cellular Microbiology, University of Reading, said:

“The finding of coronavirus mutants is entirely predictable, as mutations of this nature are the result of a normal biological process.  This new research describes a strain of SARS-CoV-2 identified in Italy and the USA that causes a disease of similar severity to the original strain, but which could spread more readily due to an infected individual producing larger quantities of the virus.

“If this particular strain is indeed able to spread even as restrictions such as travel bans are put in place, it would have made it more dangerous.  However, it’s important to note that this strain is likely to be one of the strains, if not the main one, that is currently causing the global pandemic.

“The research team also report that new versions of the virus can arise from mixing existing strains, which suggests that people may be able to become infected by multiple strains at the same time.  While mutation is a normal biological process, it should not automatically be assumed that it will make the virus more dangerous, but it remains a possibility that it could render a new vaccine of less use or enable the virus to become resistant to treatment.”

Prof Lawrence Young, Professor of Medical Oncology, University of Warwick, said:

“This a thorough and rigorous study which uses an international data base of SARS-CoV-2 sequences to track the origin and spread of this variant. It supports other observations indicating that the this variant of SARS-CoV-2 is now the globally dominant form of the virus. The press release is accurate and highlights the importance of tracking mutations in the virus and determining whether these have any impact on the spread of the virus and the development of disease.

“The observations that the G614 variant may be replicate at a higher level and that this might mean the virus is more transmissible require more detailed studies both from an epidemiological and a laboratory perspective. The data suggesting that the G614 variant is more infectious is intriguing but these studies were performed in a very artificial system and require verification.

“It looks like the G614 mutation has contributed to a ‘fitter’ virus which is more efficiently transmitted but not more pathogenic (disease causing). There is a suggestion from the common cold coronaviruses that these have changed to be more infectious but less pathogenic – resulting in a cold but not more severe disease.

“There is speculation that this mutation somehow stabilises the spike protein, thereby increasing the efficiency of infection. An unpublished preprint suggests that viruses with the G614 variant carry more spike protein in the surface of the virus.

“The current work suggests that while the G614 variant may be more infectious, it is not more pathogenic. There is a hope that as SARS-CoV-2 infection spreads, the virus might become less pathogenic!”

‘Tracking changes in SARS-CoV-2 Spike: evidence that D614G increases infectivity of the COVID-19 virus’ by Korber et al. was published in Cell

DOI: https://doi.org/10.1016/j.cell.2020.06.043

This paper was previously posted as a pre-print: https://www.biorxiv.org/content/10.1101/2020.04.29.069054v2

Declared interests

None received.