Study: Few 'important' genetic changes seen in COVID-19 since hop to humans

Study: Few 'important' genetic changes seen in COVID-19 since hop to humans
The coronavirus has evolved little since jumping to humans, at least until now, researchers say. Photo by iXimus/Pixabay

March 12 (UPI) -- The genetic makeup of the coronavirus underwent few "important" changes during the first 11 months of the pandemic, despite the emergence of potentially dangerous new strains last fall, according to a study published Friday by PLOS Biology.

After analyzing hundreds of thousands of sequenced virus genomes, researchers from the United States, Britain and Belgium documented little significant alteration in the virus' genetic structure since it jumped to humans.


This was the case until late in 2020 -- after nearly a year of the virus circulating widely among people in nearly every nation on Earth -- when new variants began to emerge as a result of limited immunity in people who'd already had the virus.

The vaccines developed to fight off the virus should continue to work, though, at least for now, the researchers said.

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"This does not mean no changes have occurred. Mutations of no evolutionary significance accumulate and 'surf' along the millions of transmission events, like they do in all viruses," study co-author Oscar MacLean said in a press release.


Most of COVID-19's evolution has been limited because humans have been "highly susceptible" to it, reducing its need to significantly mutate," said MacLean, a bioinformatician at the University of Glasgow in Scotland.

Although the precise origins of the virus that causes COVID-19 remain unknown, researchers believe it, like other coronaviruses, originated in a group of viruses found in bats, as well as in pangolins -- scaly, anteater-like animals found in Asia and Sub-Saharan Africa.

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Researchers analyzed archived samples of the virus collected from these animals, as well as humans, to identify mutations genomes and document the virus's evolutionary process.

The genetic makeup of the virus has changed significantly over time, but most of these alterations occurred before it first emerged in humans -- so it remains largely similar to viruses found in bats and pangolins -- the researchers said.

This "generalist" nature, and the ease with which the virus jumps between hosts, gives it a unique ability to infect humans and other mammals, they said.

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"What's been so surprising is just how transmissible [the coronavirus] has been from the outset," study co-author Sergei Pond said.

"Usually viruses that jump to a new host species take some time to acquire adaptations to be as capable ... at spreading, and most never make it past that stage," said Pond, a professor at Temple University's Institute for Genomics and Evolutionary Medicine in Philadelphia.


The reason the virus began to show signs of evolving again in the fall, with the emergence of new strains in England, Brazil, South Africa and elsewhere, is that more people have had the virus and are now immune to it, Pond and his colleagues said.

The new variants evolved to evade this immunity and, as a result, the virus is moving away from the strain first identified in Wuhan, China, in December 2019 -- which was used to develop the currently available vaccines -- according to the researchers.

These vaccines will continue to work against most of the circulating variants, though that may change over time, they said.

"The first race was to develop a vaccine," study co-author David L Robertson said.

"The race now is to get the global population vaccinated as quickly as possible" to protect immunity, said Roberts, a professor at the University of Glasgow Center for Virus Research in Scotland.

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