In DepthCOVID-19

The pandemic virus is slowly mutating. But does it matter?

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Science  17 Jul 2020:
Vol. 369, Issue 6501, pp. 238-239
DOI: 10.1126/science.369.6501.238


At some point early in the pandemic, one of the 30,000 letters in the genome of the new coronavirus changed from an A to a G. Today, that mutation has spread around the world; it is found in the vast majority of newly sequenced viruses and has become the center of a burning scientific question: Has the mutation become so common because it helps the virus spread faster? Epidemiology and studies in cell cultures and animals can provide clues, but the question has proved surprisingly hard to answer. Meanwhile, some researchers have noted that the virus does not appear to evolve much at all, despite having infected more than 11 million people. That raises an intriguing possibility: that SARS-CoV-2 was already well adapted to humans when it burst onto the world stage at the end of 2019, having quietly honed its ability to infect people beforehand.

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