Study Suggests Mutation May Make Coronavirus More Infectious

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(CNN) - Researchers in Florida estimate that they have shown that the new coronavirus has mutated in a way that makes it easier to infect human cells.

They say more research is needed to show whether the change has altered the course of the pandemic, but at least one researcher who was not involved in the study says yes, and the changes may explain why the virus has caused so many infections in the United States. and Latin America.

It is a mutation that scientists have been concerned about for weeks.

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Researchers at the Scripps Research Institute in Florida indicated that the mutation affects the spike protein, a structure on the outside of the virus that it uses to enter cells. If the findings are confirmed, it would be the first time that anyone demonstrates that the observed changes in the virus are of significance to the pandemic.

"Viruses with this mutation were much more infectious than those without the mutation in the cell culture system we used," Scripps Research virologist Hyeryun Choe, who helped lead the study, said in a statement.

Just this week, the World Health Organization reported that the mutations seen so far in the new coronavirus would not affect the efficacy of developing vaccines. Last week, the WHO said the mutations had not made it easier to transmit, nor had it made the virus more likely to cause serious illness.

A more stable protein

Choe and her colleagues conducted a series of laboratory experiments showing that a mutation called D614G gives the virus many more spikes and makes them more stable. That in turn makes it easier to enter cells. The researchers will publish their findings on a pre-publication platform called BioRxiv. That means the work has not been reviewed by other experts in the field.

But Choe and his colleagues submitted their work to William Haseltine, a virologist, biotech entrepreneur, and president of Access Health International. Haseltine believes the findings explain the easy spread of the coronavirus on the continent.

"It is significant because it shows that the virus can change, it changes to your advantage and possibly to our disadvantage," Haseltine told CNN. "She has done a good job so far to adapt to human culture," she added.

"You can see that in some places it doesn't go very far and in other places it has a picnic."

Scientists have been freely sharing the sequences of the virus that, like all viruses, constantly mutates. “Sometime in mid-January, there was a change that allowed the virus to become more infectious. It doesn't mean it's more deadly, "Haseltine noted. "It makes it 10 times more infectious."

Other investigators have suspected this. In April, Bette Korber of Los Alamos National Laboratory and her colleagues published their concerns, also on BioRxiv, calling the D614G mutation "of urgent concern" because it had become the most common strain in Europe and the United States.

Dominant strain

"It began to spread in Europe in early February, and when it was introduced to new regions it quickly became the dominant form," they wrote.

But more work was needed to demonstrate that it was simply not an accident that caused viruses with the D614G mutation to become the most common forms.

Haseltine said the Scripps team demonstrated this in three separate experiments.

"They measured this in three very elegant ways, not just one," he explained.

The mutation allows the virus to not only adhere to cells more easily, but is more likely to enter cells.

When viruses infect, they hijack the cells of their victims and turn them into viral factories, pumping copy after copy of virus. But first they must find a way in the cells to do this.

Korber, who has a different analysis under consideration for publication, said "it was nice to see the result," but made no further comment to CNN.

Haseltine sees the implications as important. Other researchers hoped that the coronavirus did not prove to be as prone to mutation as other viruses that use RNA instead of DNA as genetic material. The flu (influenza), known for its mutations, is an RNA virus.

"It means we have to be vigilant for constant change," Haseltine said.

"This virus will respond to whatever we do to control it. We make a medicine, it will resist it. We make a vaccine, you will try to avoid it. If we stay home, she will discover how to last longer ”, she concluded.

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