Researchers at The Scripps Research Institute have found that the strains spreading so quickly in Europe and the U.S. have a mutated S “spike” protein that makes it about 10 times more infectious than the strain that originally was identified in Asia. The research was published online on bioRxiv and has yet to be peer-reviewed.  

While the new mutation called D614G makes the virus more likely to infect people, it does not seem to make them any sicker than earlier variations of the virus. 

The scientists revealed that the D614G mutation is spreading at an alarming rate, which has reached Europe from China. It has been the leading strain in multiple regions during the outbreak in May.

The researchers also found that the genetic variation of the SARS-CoV-2 that dominates the world today infects human cells more readily than the original strain in China. 

The variant with spike G614 has replaced D614 as the dominant pandemic form, which produces higher viral loads and is more infectious in humans.  

The D614G variant makes a small but effective change in the spike glycoprotein, which comes out from the virus surface. The virus uses this spike protein to bind with the angiotensin-converting enzyme 2 (ACE2) receptors in human cells. 

Once it attaches to the receptor, it can readily enter the human cell and trigger an infection. However, when the G614 variant emerged, it quickly took over the dominant strain, which is the D614G. 

The group suggested, however, that even though the new variant is more infectious and spreads easily, it does not seem to cause more severe disease. Further, the team has found that those with the new strain of the virus had higher viral loads in the upper respiratory tract, making it more infectious.