Scientists have discovered that the European and Western strain of coronavirus is a highly mutated version. It is about 10 times more infectious than the original strain from China back in January.
A team from the Scripps Research Institute has said that the mutated strain in more resilient as the spike protein doesn't 'break off regularly' as it binds to airway cells to enter the body. As a result, the coronavirus multiplies more, increasing infection.
Mutations in viruses occur in similar ways that other living organisms change, through random genetic mutations. Previously, scientists feared that the new mutations of the virus might be making it stronger, which will make it harder for researchers to develop a vaccine.
Genetically, the former D614 strain from China has become G614 in the West, dominantly in the UK, Italy, and North America by May. Dr. Hyeryun Choe said that the spike protein appears to be compensating its previous weakness in binding to human cell receptors, or the ACE-2 receptor, the gateway in which the virus enters the body.
Ten Times Stronger
Examining the spike proteins (S) of both COVID-19 strains, Dr. Choe said, 'these results show SG614 is more stable than SD614, consistent with epidemiological data suggesting that viruses with SG614 transmit more efficiently.' With the spike ten times stronger in the new strain, it can penetrate ACE-2 receptors more easily.
Dr. Choe said, 'The epidemiological study and our data together really explain why the [G variant's] spread in Europe and the US was really fast... This is not just accidental.' However, people affected by the SG614 didn't appear to be sicker than those infected by the original virus.
Dr. Choe shared, 'an interesting question is why viruses carrying the more stable SG614 appear to be more transmissible without resulting in a major observable difference in disease severity. It is possible that higher levels of functional S protein observed with SG614 increase the chance of host-to-host transmission, but that other factors limit the rate and efficiency of intra-host replication.'
'A Clear and Consistent Pattern'
In an earlier study by the University of Sheffield and Los Alamos National Laboratory, New Mexico, scientists found that the D614 strain to be dominant in China and Asia with a mutated version in the West. 'A clear and consistent pattern was observed in almost every place where adequate sampling was available,' they said.
They also noted that wherever G614 was dominant, 'a rapid rise in its frequency followed,' allowing this strain the become dominant in a few short weeks, especially in Italy and the United States. Samples from 447 patients in Sheffield revealed that when one was infected with G614, they had more virus cells in their body compared to D614. 'An early April sampling... showed that G614's frequency was increasing at an alarming pace throughout March, and it was clearly showing an ever-broadening geographic spread,' the scientists shared.
The rapid increase in the United States followed that genetic mutation of coronavirus from the original from to G614 towards the end of March. It soon became the dominant form of the virus until today, with a high number of daily cases adding to the national count.