A new study, currently awaiting peer review and involving more than 5,000 COVID-19 patients in Houston, finds that the virus that causes the disease is accumulating genetic mutations, one of which may have made it more contagious. According to the paper posted this week to the preprint server medRxiv, that mutation, called D614G, was also implicated in an earlier study in the UK in possibly making the virus easier to spread. The Washington Post was among several outlets reporting the findings this week.
The study was carried out by scientists at Houston Methodist Hospital, The University of Texas at Austin and others. Several UT Austin authors contributed to the work: visiting scholar Jimmy Gollihar, associate professors of molecular biosciences Jason S. McLellan and Ilya J. Finkelstein and graduate students Chia-Wei Chou and Kamyab Javanmardi.
The paper shows "the virus is mutating due to a combination of neutral drift and pressure from our immune systems," said Finkelstein.
During the initial wave of the pandemic, 71 percent of the viruses identified in patients in Houston had this mutation. It has also been discovered earlier studies in the UK and Italy. When the second wave of the outbreak hit Houston during the summer, this variant had leaped to 99.9 percent prevalence. This suggests that the mutation has helped one strain outcompete other strains as they vie for dominance. The good news is that this mutation doesn't appear to make the disease more severe for infected patients and, according to Finkelstein, will not allow the virus to evade first-generation vaccines and therapeutic antibodies.
"The virus continues to mutate as it rips through the world," Finkelstein said. "Real-time surveillance efforts like our study will ensure that global vaccines and therapeutics are always one step ahead."
The scientists noted a total of 285 mutations across thousands of infections, although most don't appear to have a significant effect on how easily the virus is transmitted or how severe the disease is. Ongoing studies are characterizing how the virus is adapting to neutralizing antibodies that are produced by our immune systems. Each new infection is a roll of the dice, an additional chance to develop more dangerous mutations.
"We have given this virus a lot of chances," lead author James Musser of Houston Methodist told The Washington Post. "There is a huge population size out there right now."
The UT Austin team tested different genetic variants of the virus's spike protein, the part that allows it to infect host cells, to measure the protein's stability and to see how well it binds to a receptor on host cells and to neutralizing antibodies. Earlier in the year, McLellan and his team at UT Austin, in collaboration with researchers at the National Institutes of Health, developed the first 3D map of the coronavirus spike protein for an innovation that now factors into several leading vaccine candidates' design.
Read More:
Massive genetic study shows coronavirus mutating and potentially evolving amid rapid U.S. spread, Washington Post
More contagious coronavirus now virtually only strain in Houston, Houston Chronicle
Mutation of COVID-19 may allow it to spread more easily, Scripps National News
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