[ad_1]
London, November 27th
Mutations currently documented in the novel coronavirus that causes COVID-19 do not appear to increase its transmissibility in humans, according to a study that analyzed samples of the virus from more than 46,000 individuals worldwide.
The research, published in the journal Nature Communications, analyzed a global dataset of viral genomes of 46,723 people with COVID-19 from 99 countries, collected through the end of July 2020.
“We realized early in the pandemic that we needed new approaches to analyze huge amounts of data in near real time to signal new mutations in the virus that could affect its transmission or symptom severity,” said the author. study correspondent Lucy van Dorp of University College London in the UK.
“Fortunately, we have found that none of these mutations are causing COVID-19 to spread any faster, but we need to remain vigilant and continue to monitor for new mutations, particularly when vaccines are launched,” Van Dorp said.
According to the researchers, coronaviruses such as SARS-CoV-2 can develop mutations in three different ways: by mistake from copying errors during viral replication, through interactions with other viruses that infect the same cell, or they can be induced by the immune system of the cell. ‘guest.
Although most mutations are neutral, they said others can be beneficial or harmful to the virus, adding that both can become more common as they are passed on to descendant viruses.
In current research, the scientists identified 12,706 mutations in SARS-CoV-2 of which 398 had strong evidence that they occurred repeatedly and independently.
The researchers then delved into 185 of the 398 mutations that occurred at least three times independently during the course of the pandemic.
They modeled the evolutionary tree of the virus and analyzed whether, after a mutation first developed into a virus, its descendants outnumber closely related variants without that particular mutation.
According to the study, there was no evidence that any of the common mutations increased the transmissibility of the virus.
On the contrary, the scientists found that the most common mutations are neutral for the virus.
This includes a mutation in the virus’s peak protein called D614G, which has been widely reported as a common mutation that could make the virus more transmissible, they added.
Most of the common mutations appear to have been induced by the human immune system, rather than being the result of the virus adapting to its new human host, the scientists said.
“We previously estimated that SARS-CoV-2 entered humans in October or November 2019, but the first genomes have a date until the end of December,” said study lead author Francois Balloux of UCL.
“By then, viral mutations crucial for transmissibility in humans may have emerged and become fixed, preventing us from studying them,” Balloux said.
Scientists said that a virus mutates and eventually diverges into different lineages as it becomes more common in human populations.
However, this does not necessarily imply that more transmissible or harmful lineages will emerge, they added.
“The virus appears to be well adapted to transmission between humans, and may have already reached its optimal form in the human host by the time it was identified as a new virus,” added van Dorp.
Researchers believe the imminent introduction of vaccines may put new selective pressure on the virus to escape recognition by the human immune system.
They warned that hers could lead to the emergence of vaccine escape mutants that they said could be identified using their computational framework.
“The news on the vaccine front looks great. The virus may acquire vaccine escape mutations in the future, but we are confident that we will be able to report them promptly, which would allow vaccines to be updated in time if needed,” concluded Balloux. PTI
[ad_2]
Source link
