WEBVTT

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As the pandemic continues, variants
have become the latest concern,

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with notable examples
detected in South Africa,

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Brazil and the UK.

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But variants are complicated.

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Each one is made up
of a collection of mutations,

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all of which have the potential
to change the SARS-CoV-2 virus

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in unexpected ways.

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So what do scientists mean
when they talk about variants?

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And what might this mean
for the future of the pandemic?

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Viruses multiply by copying
their genomes over and over.

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But like an old photocopier,
these copies aren’t always perfect.

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Each of these imperfect copies
is a variant.

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Normally the imperfections or mutations
don’t change how the virus behaves,

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and they can often make it less successful
than the original strain.

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But very rarely, mutations
can change the virus

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in some important ways.

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It could become more infectious,

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or more able to avoid the immune system.

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The more a virus is allowed
to replicate unchecked,

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the more chance it has to accumulate
these rare beneficial mutations.

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That can occur when viruses

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are allowed to spread quickly
through a population,

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or if they encounter a host
that’s less able to fight them,

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such as people with compromised
immune systems from medical treatment

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or those who are HIV+.

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If a particular set of mutations
makes a variant more successful,

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it might become more prominent than others

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and that’s when it gets noticed.

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Epidemiologists may even decide
to label it a <i>variant of concern</i>,

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like the examples identified in Brazil,
South Africa and the UK.

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For months, scientists
have been striving to work out

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what’s changed in these variants,
and what those changes mean.

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Because a variant spreading
doesn’t necessarily mean

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that it has an advantageous mutation.

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For example, a small number of people
could, by chance,

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move a variant from one region to another,

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like tourists travelling back
from popular vacation spots.

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This could cause that variant to start
spreading in a new location,

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even though there may be no significant
change to the biology of the virus.

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This is called the <i>founder effect</i>.

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Understanding why a variant has emerged

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requires a combination of studies.

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Epidemiology can help detect
and trace new variants

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and flag new or worrying
patterns of infection.

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Meanwhile, lab studies
can start to pinpoint

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how the mutations are changing
the properties of the virus.

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And studies like these
are starting to identify mutations

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that have given the virus an upper hand.

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Some variants are faster spreading,
and there are hints that certain mutations

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could start to weaken or even evade
natural and vaccine derived immunity.

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For example, the D614G mutation,
known to virologists as Doug,

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spread widely
in the early days of the pandemic

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and can be seen in almost all variants.

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It affects the spike protein

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that coronavirus particles
use to penetrate cells.

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A mutation in the genome
changes one amino acid for another,

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and makes the new variant
more infectious than the original virus.

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N501Y, also known as Nelly,
is another spike protein mutation

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which appears to be associated
with increased transmissibility.

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This mutation has been detected
in the B.1.1.7, B.1.351

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and P.1 strains-- all variants of concern.

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The worry of so-called <i>immune escape</i>
has also been hinted at

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with another spike protein mutation:
E484K or Eek.

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Eek has been spotted in B.1.351 and P.1,

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the variants detected
in South Africa and Brazil.

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Lab studies in early in 2021
showed that the variant could evade

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some virus-blocking antibodies,

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while trials in South Africa suggested

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that the variant reduced
the efficacy of several vaccines.

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Despite these worries, the coronavirus
is actually mutating very slowly

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compared to something like influenza,

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and it seems like the vaccines
developed so far

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will remain at least partly effective.

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But scientists are still taking the threat
posed by variants seriously.

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And there are several things
that can be done to help tackle it.

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Firstly, to do anything,
researchers need data.

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It’s very important to monitor and trace
the emergence of variants,

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and that isn’t always simple to do.

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Organisations like the COVID-19
Genomics UK Consortium, or COG-UK,

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have stepped up their efforts
to combine fast sequencing

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with efficient data sharing.

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COG-UK has already sequenced
over 400,000 SARS-CoV-2 genomes.

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Next, researchers need to look forward
to how these mutated viruses

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could affect global vaccination efforts.

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Existing vaccines can be redesigned

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and combinations of vaccines
are also being tested,

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but it could be difficult
to perform reliable clinical trials

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amid the ongoing vaccination programmes.

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Right now though, work needs
to continue at a national level.

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Public health policies,
such as track and trace,

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social distancing and vaccine roll-outs

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are powerful tools
to interrupt transmission

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and keep tabs on new variants.

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After all, every time the virus
is prevented from spreading,

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it's also prevented from mutating,

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nipping new variants in the bud
before they even have a chance to develop.

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♪ (music) ♪