According to University College London researchers, none of the mutations of the SARS-CoV-2 virus seem to accelerate the transmissibility in humans.

For the study, the researchers analysed virus genomes from more than 46,000 Covid-19 positive people from 99 countries. Their study was published in the journal Nature Communications.

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First and corresponding author Dr Lucy van Dorp (UCL Genetics Institute) said in a statement: “The number of SARS-CoV-2 genomes being generated for scientific research is staggering. We realised early on in the pandemic that we needed new approaches to analyse enormous amounts of data in close to real-time to flag new mutations in the virus that could affect its transmission or symptom severity.”

He added: “Fortunately, we found that none of these mutations are making Covid-19 spread more rapidly, but we need to remain vigilant and continue monitoring new mutations, particularly as vaccines get rolled out.”

The researchers said that they have so far identified 12,706 mutations in SARS-CoV-2. For 398 of the mutations, there is strong evidence that they have occurred repeatedly and independently.

Of those, the researchers focused on 185 mutations which have occurred at least three times independently during the coronavirus pandemic.

The researchers modelled the virus's evolutionary tree in order to know about its transmissibility.

The researchers found no evidence that any of the common mutations are increasing the virus’s transmissibility. Instead, they found most common mutations are neutral for the virus. This includes one mutation in the virus spike protein called D614G, which has been widely reported as being a common mutation that may make the virus highly transmissible.

The new evidence finds that this mutation is in fact not associated with significantly increasing transmission.

The researchers found that 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 novel human host.

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Lead author Professor Francois Balloux (UCL Genetics Institute) added: “We may well have missed this period of early adaptation of the virus in humans. We previously estimated SARS-CoV-2 jumped into humans in October or November 2019, but the first genomes we have a date to (is) the very end of December. By that time, viral mutations crucial for the transmissibility in humans may have emerged and become fixed, precluding us from studying them."

Dr van Dorp said: “The virus seems well adapted to transmission among humans, and it may have already reached its fitness optimum in the human host by the time it was identified as a novel virus.”

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