6 March 2021 | New Scientist | 7SIX people in the UK have tested
positive for the P.1 coronavirus
variant first detected in Brazil. Five
of the six either recently returned
from Brazil or had close contact
with someone travelling from
there. Officials are trying to trace
a sixth person who tested positive
after sending in a home test kit
without contact details. The
situation has led to fears that this
variant could spread more widely.
The P.1 variant seems to have
emerged in Brazil last November.
It caused a second wave of
infections in the city of Manaus,
despite up to three-quarters of its
population having been infected
in the first wave earlier in 2020.
A study by Nuno Faria at
Imperial College London and his
colleagues suggests that P.1 spread
1.4 to 2.2 times faster than other
variants present in Manaus andreinfected between 25 and 61 per
cent of people with immunity to
these other variants.
But the researchers stress that
the findings are specific to Manaus
and don’t necessarily mean that
P.1 will spread faster in other places
with different existing variants
and different levels of immunity.
Indeed, while P.1 has now been
detected in at least 25 countries,
local transmission has been
reported only in Sweden, Belgium,
Mexico and Colombia.
So far, P.1 doesn’t seem to be
taking off in the same way as
the fast-spreading B.1.1.7 variant
first detected in the UK, but Faria
cautions that it is too early to
draw any conclusions.While it remains unclear if P.
is more transmissible outside
Brazil, there is good evidence
that both P.1 and the similar
B.1.351 variant first spotted in
South Africa have mutations
that enable them to partly evade
antibodies from vaccinations
or from previous infections.
Thankfully, these variants
cannot completely evade immune
protection. Our bodies produce
both antibodies that prevent the
virus from infecting cells in the
first place and T-cells that destroy
infected cells to stop the virus
making more copies of itself.
To prevent infection, antibodies
have to bind to key sites on the
spike proteins that protrude fromThe P.1 variant of coronavirus could be more transmissible, but
vaccines should still provide protection, reports Michael Le PageBrazil variant reaches UK
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the virus. Mutations in these sites
can reduce antibody effectiveness.
By contrast, T-cells are effective
as long as they recognise any part
of a spike protein. This means it is
much harder for a virus to mutate
to evade the T-cell response.
“There is no way these variants are
escaping T-cell immunity,” Shane
Crotty at the La Jolla Institute for
Immunology in California told
New Scientist in January.Trials of the Johnson & Johnson
vaccine found that it was slightly
less effective at preventing
symptomatic covid-19 in South
America, where P.1 is more
common, than in the US. However,
the difference was small – 66 per
cent instead of 72 per cent – and
it was still 100 per cent effective
at stopping hospitalisations and
deaths. This is reassuring because
it means that variants like P.
won’t wipe out all the benefits
of vaccination even if they do
start spreading widely.
That said, there are still two
worries. First, if P.1 reaches a
number of vulnerable people
in the UK who haven’t yet been
vaccinated, hospital admissions
could soar again.
Second, the more widely that
variants such as P.1 circulate,
the more opportunity they have
to evolve further. For instance,
the B.1.1.7 variant appears to
have now acquired the same
E484K mutation that helps P.
dodge antibodies.
However, there is a limit to
what evolution can achieve. It is
likely that many mutations have
“fitness costs” as well as “fitness
benefits”, says Astrid Iversen at the
University of Oxford. This might
explain why other variants with
the E484K mutation that appeared
early in 2020 died out instead of
spreading widely. ❚People arriving in the
UK from Brazil have to
quarantine for 10 days“ It is likely that many
coronavirus mutations
have fitness costs as
well as fitness benefits”Daily coronavirus news round-up
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