New evidence shows D614G increases infectivity of COVID-19 virus
By She Jingwei

A new study published in the journal Cell showed that a variant of the SARS-CoV-2 virus genome, previously associated with wide spread of COVID-19 and the increasing transmission of the coronavirus, has become the most prevalent form in the global pandemic.

The study, led by investigators at Los Alamos National Laboratory, suggested the variant, known as D614G, has basically replaced the previous identified virus strain D614. It has made a small but effective change in the virus's Spike (S) protein.

Dynamic tracking of variant frequencies discovered a recurrent pattern of G614 increase at national, regional and municipal levels, even in local epidemics where the original D614 form was well established prior to the introduction of the G614 variant. This shows the G614 variant may have a fitness advantage. 

Furthermore, the new strain was rare outside Europe before March 1, but by the end of the month, it had shown signs of widespread transmission among the public. The main reason for the higher speed of D614G transmission is that the mutated virus replicates faster in the upper respiratory tract in the human body, but not increased case severity.

Bette Korber, a theoretical biologist, as well as the leading author of the study, said the findings highlight again the importance of wearing a face mask and practicing social distancing in the public.

The British and the American research team also published preliminary research results showing 14 variants have already been found in the SARS-CoV-2 as early as April 30, on website bioRxiv, .

This is in line with a a previous report from Healthline website that SARS-CoV-2, regarded as a kind of RNA virus, is more prone to changes and mutations compared with DNA viruses such as herpes and smallpox; but usually becomes weaker in the process of mutation. 

The results of the study shed light on the mechanistic understanding of the virus, and help support the development of immunological interventions through the ongoing surveillance of spike mutations.

(Cover photo via VCG)