A global study has found clear evidence that a new form of the coronavirus has spread from Europe to the US The new mutation makes the virus more infectious, but it doesn’t appear to make people sicker, a team reported Thursday. International Association of Researchers.
The mutation affects the spike protein, the structure the virus uses to enter the cells it infects. Now researchers are checking to see if this affects whether the virus can be controlled by a vaccine. The current vaccines being tested are primarily aimed at the spike protein.
The study, published in the journal Cell, confirms previous work suggesting that the mutation had made the new variant of the virus more common. The researchers call the new mutation G614, and show that it has almost completely replaced the first version that spread in Europe and the United States, a one called D614.
“Our global tracking data shows that the G614 variant on Spike has spread faster than D614,” theoretical biologist Bette Korber of the Los Alamos National Laboratory and colleagues wrote in their report. “We interpret this to mean that the virus is likely to be more infectious,” they add. “Interestingly, we found no evidence of the impact of G614 on the severity of the disease.”
What does this mean: This could be good news, said Lawrence Young, a professor of medical oncology at the University of Warwick in the United Kingdom, who was not involved in the study. “Current work suggests that while the G614 variant may be more infectious, it is not more pathogenic. There is hope that as the SARS-CoV-2 infection spreads, the virus could become less pathogenic, “it said in a statement.
About the study: The team tested samples taken from patients across Europe and the US and sequenced the genomes. They compared these genome sequences with what has been shared publicly. Comparing these sequences helped them draw a map of the spread of the two forms.
“As of March 1, 2020, the G614 variant was rare outside of Europe, but by the end of March it had increased in frequency worldwide,” they wrote.
Even when the D614 form had caused widespread epidemics, in places like Wales and Nottingham in England, as well as in Washington state, they discovered that G614 took over once it appeared.
“The increase in G614 frequency often continues long after the stay-at-home orders are in place and after the two-week incubation period,” they added.
The new version appears to multiply faster in the upper respiratory tract, nose, sinuses and throat, which would explain why it happens more easily, the researchers said. But tests on 1,000 hospitalized patients with coronavirus showed that those infected with the new version fared no worse than those who caught the original strain.
Other mutations often go along with the G614 mutation, but it is unclear what effect they have. “The first sequence we detected carrying the 4 mutations was sampled in Italy on February 20,” they wrote. “In a matter of days, this haplotype was sampled in many countries in Europe.
The G614 mutation can be neutralized with convalescent serum, the blood product taken from people who have recovered from a coronavirus infection, the researchers said.
“But it will be important to determine whether the D614 and G614 forms of SARS-CoV-2 are differentially sensitive to neutralization by vaccine-induced antibodies or by antibodies produced in response to infection with either form of the virus,” they added.
More work is needed, of course, to solidify the findings and see what the changes mean for the epidemic and for patients, the researchers said.
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