After examining coronavirus
samples of more than 46,000 individuals from across the world, a study revealed that mutations currently reported in the novel coronavirus, which causes COVID-19, do not seem to increase its transmissibility in humans.

The research surveyed
a global dataset of viral genomes from 46,723 people infected with coronavirus from
99 countries, collected up till July 2020.

The research was
published in the journal Nature Communications.

“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,” said study
corresponding author Lucy van Dorp from the University College London in the

She confirmed that
none of the mutations are contributing to COVID-19’s spread. She pressed on the
need to remain vigilant and monitor new mutations.

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According to
researchers, coronaviruses like SARS-CoV-2 undergo mutations in three ways – due
to copying errors during viral replication, through interactions with other
viruses infecting the same cell, or they can be induced by the host’s immune

While most mutations
are neutral, some can be beneficial or harmful to the virus. Whatever effect
they may have on the virus, it will get passed on to its descendants.

In the current
research, the scientists identified 12,706 mutations in SARS-CoV-2. There is
strong indication that of these, 398 mutations have occurred repeatedly and
independently. Digging in further, they found that 185 of the 398 mutations occurred at least three times independently during the course of the pandemic.

They built an evolutionary tree of the virus, and studied whether after the development of
the first mutation in a virus, if its descendants perform better than the
closely related variants without the mutation or not.

There was no factual
proof suggesting that mutations led to increased transmissibility. In fact,
scientists discovered that the most common mutations had no effect on the

Most of the mutations
are induced by the host’s immune system, rather than by the virus adapting to
its human host, scientists said.

“We previously
estimated SARS-CoV-2 jumped into humans in October or November 2019, but the
first genomes we have date to the very end of December,” said study lead
author Francois Balloux from UCL.”By that time, viral mutations crucial
for the transmissibility in humans may have emerged and become fixed,
precluding us from studying them,” Balloux said.

The fact that viruses
diverge into different lineages post mutations does not entail that the new
lineages will be more transmissible or harmful, scientists 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,” van Dorp added.

The researchers think
that the virus may try to elude the human immune system to avoid its recognition,
in light of the imminent introduction of vaccine. This may lead to the
surfacing of vaccine-escape mutants, which they said they could identify with
their computational framework.

“The news on the
vaccine front looks great. The virus may well acquire vaccine-escape mutations
in the future, but we’re confident we’ll be able to flag them up promptly,
which would allow updating the vaccines in time if required,” Balloux