Omicron variant may have picked up a piece of common-cold virus
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[December 04, 2021]
By Nancy Lapid
NEW YORK (Reuters) - The Omicron variant of
the virus that causes COVID-19 likely acquired at least one of its
mutations by picking up a snippet of genetic material from another virus
- possibly one that causes the common cold - present in the same
infected cells, according to researchers.
This genetic sequence does not appear in any earlier versions of the
coronavirus, called SARS-CoV-2, but is ubiquitous in many other viruses
including those that cause the common cold, and also in the human
genome, researchers said.
By inserting this particular snippet into itself, Omicron might be
making itself look "more human," which would help it evade attack by the
human immune system, said Venky Soundararajan of Cambridge,
Massachusetts-based data analytics firm nference, who led the study
https://osf.io/f7txy posted on Thursday on the website OSF Preprints.
This could mean the virus transmits more easily, while only causing mild
or asymptomatic disease. Scientists do not yet know whether Omicron is
more infectious than other variants, whether it causes more severe
disease or whether it will overtake Delta as the most prevalent variant.
It may take several weeks to get answers to these questions.
Cells in the lungs and in the gastrointestinal system can harbor
SARS-CoV-2 and common-cold coronaviruses simultaneously, according to
earlier studies. Such co-infection sets the scene for viral
recombination, a process in which two different viruses in the same host
cell interact while making copies of themselves, generating new copies
that have some genetic material from both "parents."
This new mutation could have first occurred in a person infected with
both pathogens when a version of SARS-CoV-2 picked up the genetic
sequence from the other virus, Soundararajan and colleagues said in the
study, which has not yet been peer-reviewed.
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People queue at a popup COVID-19 testing site in New York, U.S.,
December 3, 2021. REUTERS/Jeenah Moon
The same genetic sequence appears many times in one
of the coronaviruses that causes colds in people - known as
HCoV-229E - and in the human immunodeficiency virus (HIV) that
causes AIDS, Soundararajan said.
South Africa, where Omicron was first identified, has the world's
highest rate of HIV, which weakens the immune system and increases a
person's vulnerability to infections with common-cold viruses and
other pathogens. In that part of the world, there are many people in
whom the recombination that added this ubiquitous set of genes to
Omicron might have occurred, Soundararajan said.
"We probably missed many generations of recombinations" that
occurred over time and that led to the emergence of Omicron,
Soundararajan added.
More research is needed to confirm the origins of Omicron's
mutations and their effects on function and transmissibility. There
are competing hypotheses that the latest variant might have spent
some time evolving in an animal host.
In the meantime, Soundararajan said, the new findings underscore the
importance of people getting the currently available COVID-19
vaccines.
"You have to vaccinate to reduce the odds that other people, who are
immunocompromised, will encounter the SARS-CoV-2 virus,"
Soundararajan said.
(Reporting by Nancy Lapid; Editing by Will Dunham)
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