How will the latest coronavirus variant affect
Europe this winter?
Scientists are concerned that the B.1.1.529 mutation
could bypass immunization from both vaccination or prior infection.
BY HELEN
COLLIS
November
26, 2021 4:02 pm
A new
variant of coronavirus has sparked a frenzy of investigations and travel
interventions as experts seek to get ahead in understanding just how serious
this mutation really is.
The
variant, named by the World Health Organization as Omicron, was first detected
by genomic sequencing in South Africa and shared with an international database
on November 22.
“This
variant has a large number of mutations, some of which are concerning,” the WHO
said in a statement on Friday. “Preliminary evidence suggests an increased risk
of reinfection with this variant, as compared to other [variants of
conerns]."
Jenny
Harries, head of the U.K.’s Health Security Agency said earlier this was the
“most significant variant we have encountered to date” and said “urgent
research” was underway to understand more.
In response
to concerns raised by scientists, the U.K. government, followed by others in
Europe, announced significant restrictions to travel from South Africa,
Botswana, Lesotho, Eswatini, Zimbabwe and Namibia. But the variant has already
spread to Europe, with one case detected in Belgium.
Here’s what
we know so far about the variant — and what we don’t know.
Why have
scientists raised concerns about this variant?
The Omicron
variant, also known as B.1.1.529, contains around 50 mutations, an unusually
large number. More than 30 of these are in the spike protein, the part of the
SARS-CoV-2 virus that interacts with human cells prior to cell entry — and the
part most vaccines target.
While
several of those mutations have been observed in earlier variants of concern,
“some of those mutations have rarely been observed together in the same strain
before,” said Francois Balloux, director of University College London’s
Genetics Institute.
Genomic
sequencing in South Africa has so far identified 100 Omicron cases from the
region that includes the cities of Johannesburg and Pretoria. Previously low
overall daily COVID-19 case rates in that part of the country have spiked over
the past seven days from 273 to more than 1,200.
Will my
vaccine still protect me?
Based on
the number and types of mutations seen in the Omicron variant, scientists
suggest that immunity through vaccination and/or prior infection may not
protect against re-infection by Nu so effectively.
“Based on
its genetic makeup, we can confidently predict B.1.1.529 may partly bypass
immunization provided by vaccination and prior infection,” said Balloux.
That’s
because mutations in Omicron “have been associated in other variants with
immune evasion,” pointed out Sharon Peacock, director of COG-UK Genomics U.K.
Consortium.
But it will
be a few weeks before we know for sure.
Lab studies
are being conducted rapidly in South Africa to understand the impact on
immunity. Scientists are looking at antibody neutralization of this variant as
well as interactions with T cells, to “confirm whether there is reduced
immunity in standard lab assays, but these will take several weeks to
complete,” said Peacock, who is also professor of public health and
microbiology at the University of Cambridge.
Meanwhile,
there is currently no real-world evidence that immunity to vaccines and past
infection is reduced, she said, and these studies are needed.
Is this
variant likely to become dominant in Europe?
This is
unknown at this stage. Current data shows a spike in cases particularly in the
Gauteng province of South Africa.
“The
epidemiological picture suggests that this variant may be more transmissible,
and several (of the Omicron) mutations are consistent with enhanced
transmissibility,” said Peacock. But it was not yet clear whether this was due
to super-spreading events or whether the Omicron variant can in fact outcompete
the now-dominant Delta strain. "Further studies are required to confirm this,”
Peacock said.
“Any
prediction about its transmissibility and virulence feels premature,” added
Balloux. “While we can work out the contribution to transmissibility and
virulence of mutations in isolation, we still struggle to accurately predict
their effect when found in combination.”
Is this
variant more deadly?
Once again,
data on this is still pending, and will most likely come from ongoing
surveillance in South Africa.
One school
of thought suggests that if Omicron is more transmissible, it may be less
dangerous — from the evolutionary point of view a virus risks extinction if it
is too effective at killing its host. This could also be the case with the
Delta sub-lineage AY.4.2 which is gaining pace in the U.K.
Meanwhile,
some suggest that the cellular immune response induced by vaccines may be
sufficient to fight off the virus even with multiple mutations.
Monica
Gandhi, an infectious diseases/HIV doctor at University of California, San
Francisco, tweeted that, since the cellular immune response is very complex —
generating new types of antibodies even against new variants — there is a
chance vaccines will remain protective.
How can we
protect ourselves?
It’s still
not known to what extent the Omicron variant may escape vaccine immunity.
Experts urge people to get their full course of vaccination, including boosters
if eligible.
The U.K.
and Europe have taken quick action to try to stem the flow of the Omicron
variant into the region, through temporarily stopping flights and introducing
new quarantine measures.
“Early
action is far better than late action,” said Ewan Birney, deputy director
general of European Molecular Biology Laboratory and director of EMBL’s
European Bioinformatics Institute. “It may turn out that this variant is not as
large a threat as Alpha and Delta, but the potential consequences of not acting
on the possibility it could be are serious,” he added.
Meanwhile,
the international community “should get drugs and vaccines to South Africa as
soon as possible,” he added.
If we need
new vaccines, how long would it take to make them?
The most
widely used vaccine in Europe has been the mRNA COVID-19 shot from
BioNTech/Pfizer. These companies are looking out for vaccine escape variants,
including Omicron.
“We expect
data from the laboratory tests in two weeks at the latest,” a spokesperson for
BioNTech said. “These data will provide more information about whether
B.1.1.529 could be an escape variant that may require an adjustment of our
vaccine if the variant spreads globally."
Pfizer
Chief Executive Albert Bourla said in September that the two companies could
develop a new version of the vaccine that is tailor-made made to a new variant
in “less than 100 days.”
The
companies have already done this for the Beta variant, also first identified in
South Africa, and Delta. But since the current vaccine has remained effective
against these variants, there has not yet been any need to bring a modified
version to market.
Earlier
this month, BioNTech announced it was developing a prototype approach to
evaluate the development, manufacturing and regulatory processes for variant
specific vaccines, so they could arrive much quicker.
“The idea
is that we're staying ahead of the virus,” Bourla said in September.
This
article has been updated.
Sem comentários:
Enviar um comentário