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“We find that none of the recurrent SARS-CoV-2 mutations tested are associated with significantly increased viral transmission,” reported François Balloux, Lucy van Dorp and their colleagues at University College London.
They even found that a much-discussed mutation that many researchers said made the virus easier to transmit didn’t, in fact, appear to have affected its ability to infect people. The mutation, called D614G, doesn’t do much, they found.
“Here, we find conversely that D614G does not associate with significantly increased viral transmission,” they wrote.
“What is indisputable, however, is that D614G appeared at the start of the pandemic and is now found at a high frequency around the world,” they added.
It appears that this mutation is “more of a stowaway who has been lucky on a successful lineage, rather than a transmission driver,” Balloux tweeted. It just appeared at a time when the virus was starting to take off in Europe.
However, once people start getting vaccinated, that will make a difference. This will put what is called selective pressure on the virus and it will likely begin to mutate, Balloux said.
All viruses mutate and RNA viruses, a group that includes coronaviruses, mutate more than others.
They can change due to simple copy errors during virus replication. Coronaviruses do this less often than other RNA viruses because they have a built-in proofreader.
Viruses can also change when two different strains infect a host at the same time. The flu is remarkable for this.
And the infected person can also cause the virus to mutate through what is called changing the host’s RNA – part of the immune response.
Most of the mutations to date appear to have come from this third mechanism, Balloux’s team said. And they appear neutral – they haven’t hurt the virus and haven’t helped it either.
“Very deleterious mutations, such as those which prevent invasion of the host virus, will be rapidly eliminated from the population; mutations which are only slightly deleterious may be retained, if only transiently. Conversely, mutations neutral and in particular advantageous can reach higher frequencies “Wrote the team of Balloux.
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