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The coronavirus has now been with
us for over a year.

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During that time, our knowledge
about the virus

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and the disease it causes has
increased dramatically.

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MATT HANCOCK: We have identified a
new variant of coronavirus

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which may be associated with
the faster spread

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in the southeast of England.

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In this Horizon special, we will be
bringing you up to speed

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on what we know now.

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Providing you with answers direct
from the army of scientists

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and clinicians on the front line
of the fight against Covid-19.

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You didn't need a sample of virus?

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No, we absolutely didn't.

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We just needed to know the
coding sequence.

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We'll be telling you the latest
information

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about how and why viruses mutate...

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Well, we were so shocked.

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We'd all been told for many months
that this was a virus

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that doesn't really mutate
very fast.

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..how the new vaccines work and
how they were created so quickly...

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We can very quickly adapt the
sequence in the vaccine

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to adapt to those new variants.

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..and how identifying coronavirus
super-spreaders

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can help reduce infection rates.

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In the two weeks after one of these
initial cases appears,

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you can potentially double
the number

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of onward transmission events
that you prevent.

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And with the announcements
this week laying out a road map

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to lifting restrictions,

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we'll also be tackling the
biggest question of all -

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when can we get back to normal?

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Everything we're now experiencing

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is because of this tiny pathogen's

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overriding evolutionary purpose -

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to reproduce.

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Like all viruses, it acts
as a parasite.

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It can only reproduce
by infecting us

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and hijacking our own
cells' reproductive machinery.

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But incredible developments
in genetics

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and genetic engineering mean that
we are fighting back

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in ways we simply couldn't have,
even five years ago.

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The coronavirus has also moved on,
though.

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It's changing shape, it's becoming
harder to pin down.

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So far, we've seen new variants
emerge around the globe -

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South Africa, Brazil and, of course,
much closer to home.

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In November last year,

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thanks to a strict national
lockdown,

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Covid cases in the UK fell for
the first time in months.

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But in Kent, it was a
different story.

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There, infections were rising
dramatically.

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NEWSREADER: Swale in Kent is now the
second-worst hit

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area in the country.

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NEWSREADER: High numbers in a couple
of areas of Kent

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have pushed the whole county
into the toughest restrictions.

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Something didn't add up,

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so geneticists set about
decoding the genome

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from this worrying new surge in the
Garden of England.

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What they discovered was
a new variant

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with dangerous mutations.

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At the beginning of the pandemic,

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an organisation called COG-UK
was set up

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to keep tabs on how the virus
might evolve.

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They've been doing that by decoding
the genomes

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of hundreds of thousands of positive
Covid samples.

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Positive tests taken outside of
hospital come here,

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to the Wellcome Sanger Institute
in Cambridge.

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It's a huge operation.

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Over 300 people work here.

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Dr Ewan Harrison showed me around.

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These, they're a mix of positive
and negative samples.

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And then the robotics you see here
pick out the positives.

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OK.

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These machines decode the
genetic material

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and upload it to a database.

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Then, by comparing the new samples
with the original strain,

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scientists can spot mutations.

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Why are you particularly interested
in the information about mutations?

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We expect to see about one to two
mutations a month,

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accruing in a particular virus
as it transmits between people.

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And mutations, in many ways,
act like a barcode.

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So they allow us to tell the
difference between

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two types of the virus.

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So, if two people have types
of the virus

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that have different mutations,

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then we know that likely they got
the virus

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from two different sources,

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and that's the fundamental basis of
why we're doing the sequencing.

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It allows us to tell whether
two viruses

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are related to each other
or are different.

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When any organism -
including a virus - reproduces,

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mutations are created in its genome.

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If those mutations confer
an evolutionary advantage,

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they will be passed on to future
generations.

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To begin with, this virus
accumulated just one or two

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mutations each month.

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But that suddenly changed
at the end of 2020.

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But what we saw in the particular
cluster of cases

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that were in the southeast
of England

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is that they had 23 different
mutations across the virus.

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It suddenly jumped to having 23?

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Yeah. I mean, it was a surprise.

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MATT HANCOCK: We have identified
a new variant of coronavirus

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which may be associated with
the faster spread

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in the southeast of England.

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The new variant of coronavirus has
a much quicker transmission rate

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than the original strain.

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The new variant of coronavirus is
spreading rapidly.

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The new variant...
The new variant...

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The new variant...

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The new variant of coronavirus
is out of control.

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The new mutation was spreading
at an alarming rate.

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Professor Ravi Gupta was determined
to find out why.

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What went through your head when you
realised there was a new variant,

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there was something spreading fast
and it had 23 mutations

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coming out of the southeast
of England - the new variant?

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Well, we were so shocked

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that we almost didn't believe
the sequencing, you know?

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We'd all been told for many months
that this was a virus

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that doesn't really mutate
very fast.

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Ravi works as a clinician at
Addenbrooke's Hospital.

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There, he saw a patient whose immune
system had been weakened

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by chemotherapy, and who'd been sick
with Covid-19

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for over three months.

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That case would reveal a vital clue
about how the virus could evolve

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so quickly in other parts
of the country.

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So, he'd been infected for 100 days,

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and part of the reason was the fact
that his immune system

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wasn't working properly.

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And that allowed the virus
to keep replicating

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and making a lot of copies.

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Doctors administered antibodies
donated from recovered patients,

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hoping they would help fight
the virus.

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Unfortunately, there was so much
virus there

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that the antibodies couldn't cure
the patient of a Covid-19.

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But what it did allow is for that
virus to learn

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how to get around those antibodies.

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We noticed that the virus
started shifting,

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it started making mutations.

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By the time the patient died,

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Ravi's team had identified
37 mutations in the virus.

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This led scientists to believe that
new variants

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like the one found in Kent

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may evolve in the bodies of patients
with weakened immune systems.

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Most of us, of course,
clear this virus in a week or so.

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This patient had it
for many, many weeks.

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And because they were being exposed
to new antibodies,

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that is what gave that virus
an accelerated chance to evolve?

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That's right. And so we were fairly
certain that this is the cause

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for the new variants that are
circulating around the world

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at the moment.

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Mutations in the spike protein
may also affect

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how our current vaccines work.

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The spike is the part of the virus
that they target.

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We're now in the era of vaccination,

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but there will be more pressure
on this virus

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to adopt mutations that enable it
to avoid

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vaccinated people's immunity.

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And I can already see there are
three or four mutations

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causing us severe trouble.

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So we already need to change our
vaccines in the immediate future,

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and we'll probably need to do it
in the years to come.

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Mutations are a huge concern.

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As long as there is transmission,
this virus will continue to evolve.

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Now, the variants we've seen so
far don't appear

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to be much more deadly.
Our vaccines do still work.

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But variants will emerge
that can escape the vaccine,

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and when they do, it's the people
here and at Wellcome Sanger

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that are going to be
the first to know.

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I'm joined by Professor
Sharon Peacock.

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She's the director of
Covid-19 at Genomics UK,

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also known as COG-UK,

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a consortium set up to monitor
the progress of the virus

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and also advise the UK Government.

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Sharon, by now everyone has heard of
at least four variants -

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South Africa, Brazil, the UK,
and now Nigeria.

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What are the things that
we worry about

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with each of these variants?

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The first is, is a virus
more transmissible?

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The second is, will it avoid
our immune system?

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The third is, could it be more
lethal for us

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and kill more people?

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And finally, could it affect our
diagnostic tests and avoid them?

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We've got a graphic here
of UK variants.

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So, if we look at the cluster of
red bars, there,

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what we're seeing there is a variant
that first arose probably in Spain,

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and it appeared to transmit
very rapidly

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and markedly throughout Europe.

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And that is summer holiday travel.

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And so this particular variant was
transmitted by people

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travelling during their
summer holidays

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and importing this, and it moving
around Europe through travel.

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And it's a large number of people
carrying this virus back

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that account for the large number
of cases -

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it's NOT that it's good
at spreading.

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Now, with the sort of
greeny-yellow one

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that then really explodes from sort
of mid-December

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out to the current time.

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So that's the variant that we've all
become very familiar with now -

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B117, or some people refer to it
as the Kent variant.

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And so, if you look at the green,

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by the time you get to around
mid-November,

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that you start to see cases
beginning to increase,

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and is now by far and away the most
common cause

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of Covid-19 in this country.

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Now, the difference there is it
WAS the virus

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that had changed its biology

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and had led to more rapid
transmission between people.

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So it spread through the population
very quickly -

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not a function of people
transmitting it

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through travel or similar,

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but because of a property of
the virus.

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So a variant might be fitter
if it's more able to transmit.

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What about changes that we see
in these variants

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that allow them to evade the
immune system?

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We know about the, quite famous now,
mutation E484K.

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That's a very good example of where
the virus has changed

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a particular amino acid,
a building block for a protein,

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which has led to a change
in the spike protein

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which attaches to human cells.

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Now, when that spike protein
changes very slightly,

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the ability to neutralise that

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and that interaction between the
spike and the human cell

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is reduced.

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So that's the mechanism by which
immunity is evaded.

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And the mutation means it can get
through a chink in the armour

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of our immunity and
still infect somebody.

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So have we seen that E484K mutation
arise more than once?

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Yes, and so it's certainly present
in the variant

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that we're concerned about that's
arisen

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first in South Africa,

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and the one that we detected in
Brazil, and various others.

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And are we likely to see more
variants emerge

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where their immunity to either
our immune systems,

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if we've been previously infected
or if we've been vaccinated,

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where that gives them an advantage?

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Will we see vaccine-resistant
strains?

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The variants that are arising
at the moment

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may have a partial resistance to the
vaccines we're using

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in some parts of the world.

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In the UK, I'm confident that the
vaccines we have in this country

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are fully effective against our
current variant that's circulating.

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However, what it means for the
manufacturers of vaccines

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is that they're going to be
repeatedly looking

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at the variants that are emerging
and tweaking their vaccines

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so that they remain effective.

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The other big thing, of course,
we worry about

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with all these variants is,
are they more likely to kill us?

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What do we know so far? Yes.

248
00:12:26,000 --> 00:12:29,160
There is one variant where we think
that's the case.

249
00:12:29,160 --> 00:12:31,000
It's not absolutely certain yet,

250
00:12:31,000 --> 00:12:33,000
but there's growing evidence
that the variant

251
00:12:33,000 --> 00:12:36,840
circulating in the UK at the moment,
the 117, the Kent variant,

252
00:12:36,840 --> 00:12:40,520
is more lethal than other variants -
by about 35%.

253
00:12:40,520 --> 00:12:44,000
That number sounds very scary,
but actually,

254
00:12:44,000 --> 00:12:46,880
if you were to take a group of
60-year-old people,

255
00:12:46,880 --> 00:12:50,720
and ten out of 1,000 might die
as a result of infection,

256
00:12:50,720 --> 00:12:54,040
what we're talking about here is
13 or 14 people.

257
00:12:54,040 --> 00:12:57,280
Now, that's really key for them
as individuals,

258
00:12:57,280 --> 00:12:59,280
but it's not a huge leap.

259
00:12:59,280 --> 00:13:02,120
OK, so 35% sounds like a lot,

260
00:13:02,120 --> 00:13:04,320
but when you actually look at
the numbers,

261
00:13:04,320 --> 00:13:06,800
it's not a massive,
absolute increase.

262
00:13:11,600 --> 00:13:13,400
Just a few years ago,

263
00:13:13,400 --> 00:13:15,680
a fast-mutating virus might have
been a problem

264
00:13:15,680 --> 00:13:17,880
for an effective vaccine programme,

265
00:13:17,880 --> 00:13:19,880
but vaccines have changed.

266
00:13:19,880 --> 00:13:22,480
So how does up-to-the-minute
gene manipulation

267
00:13:22,480 --> 00:13:24,560
help beat the virus at its own game?

268
00:13:31,360 --> 00:13:34,960
230 years ago,
Edward Jenner worked out

269
00:13:34,960 --> 00:13:38,600
that he could prevent smallpox
using the closely related

270
00:13:38,600 --> 00:13:40,960
but less deadly cowpox virus.

271
00:13:43,560 --> 00:13:46,120
This technique became known
as vaccination -

272
00:13:46,120 --> 00:13:48,560
from vacca, Latin for cow.

273
00:13:48,560 --> 00:13:51,640
And it's because of this idea
that we stand any chance

274
00:13:51,640 --> 00:13:53,560
of defeating Covid at all.

275
00:13:55,360 --> 00:13:58,440
The contents of this vial
are one of the most

276
00:13:58,440 --> 00:14:02,520
astounding success stories
in modern science.

277
00:14:02,520 --> 00:14:06,600
It is, of course, one
of the new vaccines for Covid-19.

278
00:14:08,160 --> 00:14:13,080
Each dose contains
50 billion life-protecting

279
00:14:13,080 --> 00:14:14,920
particles of vaccine.

280
00:14:20,000 --> 00:14:22,280
Vaccines are typically made from
a virus

281
00:14:22,280 --> 00:14:24,600
that has been weakened or killed.

282
00:14:24,600 --> 00:14:27,960
Once vaccinated, our immune system
remembers the shape of it

283
00:14:27,960 --> 00:14:29,600
without making us ill.

284
00:14:31,400 --> 00:14:33,800
And then, if we encounter the virus
for real,

285
00:14:33,800 --> 00:14:36,560
our bodies are primed to
neutralise it.

286
00:14:36,560 --> 00:14:38,960
Vaccines for measles and many
other diseases

287
00:14:38,960 --> 00:14:40,360
are made like this.

288
00:14:44,000 --> 00:14:47,080
But in recent years,
scientists have been rethinking

289
00:14:47,080 --> 00:14:48,720
the way that vaccines work,

290
00:14:48,720 --> 00:14:52,800
and they've come up with some
really revolutionary approaches.

291
00:14:52,800 --> 00:14:55,720
They all rely on the latest
in genetic engineering

292
00:14:55,720 --> 00:14:59,480
so that the genome of the virus
is at the heart of the vaccine.

293
00:15:03,440 --> 00:15:05,360
I've come to Oxford BioMedica,

294
00:15:05,360 --> 00:15:08,360
and this is where the Oxford
AstraZeneca vaccine

295
00:15:08,360 --> 00:15:09,920
is being manufactured.

296
00:15:09,920 --> 00:15:12,800
It's one of the new generation
of vaccines.

297
00:15:15,320 --> 00:15:18,720
This new generation is radically
different

298
00:15:18,720 --> 00:15:22,000
because you only need to know
the genetic code of the virus

299
00:15:22,000 --> 00:15:24,440
to start development.

300
00:15:24,440 --> 00:15:26,920
One of the key scientists who helped
design it

301
00:15:26,920 --> 00:15:28,840
is only two miles down the road,

302
00:15:28,840 --> 00:15:31,840
but researchers in this field need
to be extra careful,

303
00:15:31,840 --> 00:15:35,320
so I'm talking to
Professor Teresa Lambe remotely.

304
00:15:35,320 --> 00:15:39,200
So, to start designing your vaccine,

305
00:15:39,200 --> 00:15:42,000
you didn't need a sample of virus?

306
00:15:42,000 --> 00:15:43,360
No, we absolutely didn't.

307
00:15:43,360 --> 00:15:47,200
We just needed to know the
coding sequence.

308
00:15:47,200 --> 00:15:50,040
The email came in late Friday,
early Saturday -

309
00:15:50,040 --> 00:15:54,320
that arrived in my inbox from a good
friend of mine at the NIH.

310
00:15:54,320 --> 00:15:57,640
And then there was more database
updating over the weekend.

311
00:15:57,640 --> 00:16:00,360
And I spent that weekend,
myself and colleagues,

312
00:16:00,360 --> 00:16:05,280
working on designing what we thought
would be the most effective

313
00:16:05,280 --> 00:16:08,120
part of the coronavirus to include
in a vaccine,

314
00:16:08,120 --> 00:16:09,720
and how to do that.

315
00:16:13,800 --> 00:16:16,280
Within a few days of receiving
the genetic code

316
00:16:16,280 --> 00:16:18,720
for the protein spike,

317
00:16:18,720 --> 00:16:21,560
Tess was using it to make
the vaccine.

318
00:16:25,640 --> 00:16:28,400
What we've done is, we've taken the
spike protein,

319
00:16:28,400 --> 00:16:30,960
and that's a small, tiny part of the
virus -

320
00:16:30,960 --> 00:16:32,520
the outside of the virus -

321
00:16:32,520 --> 00:16:36,360
that allows the virus to get into
our body and into our cells.

322
00:16:38,360 --> 00:16:41,400
Only this spike code is needed to
make a vaccine

323
00:16:41,400 --> 00:16:43,680
that will prime the body's
immune response.

324
00:16:43,680 --> 00:16:45,720
The whole virus isn't required.

325
00:16:48,600 --> 00:16:53,200
The spike's genetic code is then
spliced into the DNA of a vector -

326
00:16:53,200 --> 00:16:56,080
a biological container that
transports

327
00:16:56,080 --> 00:16:58,680
the viral genetic material
into our cells.

328
00:17:02,360 --> 00:17:05,000
For the vector, Tess used an
adenovirus -

329
00:17:05,000 --> 00:17:07,880
a mild cold virus which had been
rendered harmless

330
00:17:07,880 --> 00:17:09,680
by further genetic engineering.

331
00:17:11,760 --> 00:17:14,560
The vaccine can then be injected
into the upper arm,

332
00:17:14,560 --> 00:17:16,560
where it enters individual
muscle cells.

333
00:17:18,200 --> 00:17:20,800
These cells read the genetic code
for the protein

334
00:17:20,800 --> 00:17:23,240
and create spikes on their surface.

335
00:17:24,840 --> 00:17:28,560
The immune system identifies these
strange-looking spikes

336
00:17:28,560 --> 00:17:31,440
as foreign, and produces
memory cells

337
00:17:31,440 --> 00:17:33,640
that will remember this
spike protein.

338
00:17:35,680 --> 00:17:37,880
The vaccine can't cause
an infection,

339
00:17:37,880 --> 00:17:40,160
but it primes the immune system.

340
00:17:40,160 --> 00:17:43,400
This army of memory cells will
spring into action,

341
00:17:43,400 --> 00:17:47,000
producing antibodies and T-cells,
should it ever encounter

342
00:17:47,000 --> 00:17:48,320
the virus for real.

343
00:17:49,920 --> 00:17:52,160
So it's a bit like a Trojan horse.

344
00:17:52,160 --> 00:17:56,000
Your body thinks that it's seeing an
invading virus in your arm

345
00:17:56,000 --> 00:17:58,800
and it mounts a really strong immune
response towards it.

346
00:18:02,920 --> 00:18:04,360
Over in Germany,

347
00:18:04,360 --> 00:18:07,960
the Pfizer BioNTech team have used
a different technique.

348
00:18:07,960 --> 00:18:09,600
Like the Oxford vaccine,

349
00:18:09,600 --> 00:18:12,840
they isolated the genetic code of
the spike protein.

350
00:18:12,840 --> 00:18:14,680
But instead of using DNA,

351
00:18:14,680 --> 00:18:16,720
they used messenger RNA -

352
00:18:16,720 --> 00:18:18,760
also found in a cell's nucleus -

353
00:18:18,760 --> 00:18:22,840
and they inserted it
into a tiny drop of fat.

354
00:18:22,840 --> 00:18:25,360
Then, once injected, it creates
immunity,

355
00:18:25,360 --> 00:18:27,080
just like the Oxford vaccine.

356
00:18:28,880 --> 00:18:31,120
So, by spring 2020,

357
00:18:31,120 --> 00:18:34,280
both the Pfizer
and the Oxford AstraZeneca teams

358
00:18:34,280 --> 00:18:37,200
had finalised their vaccines.
They'd made them.

359
00:18:37,200 --> 00:18:40,280
You know, I cannot emphasise enough
how quick that is.

360
00:18:42,440 --> 00:18:45,120
Before Covid, the fastest a vaccine
for a new disease

361
00:18:45,120 --> 00:18:48,360
had ever been made and licensed
was around five years.

362
00:18:49,600 --> 00:18:51,360
Yet, in just nine months,

363
00:18:51,360 --> 00:18:55,560
and after thorough testing on over
24,000 volunteers,

364
00:18:55,560 --> 00:18:59,520
the Oxford vaccine was shown to be
both safe and effective.

365
00:19:02,200 --> 00:19:05,240
New-generation vaccines have
an added advantage.

366
00:19:06,720 --> 00:19:09,520
Because you don't need to work
with the real Covid virus

367
00:19:09,520 --> 00:19:10,880
under strict controls,

368
00:19:10,880 --> 00:19:14,400
they can be quicker and easier
to mass-produce.

369
00:19:14,400 --> 00:19:17,760
AstraZeneca is collaborating
with Oxford on the new vaccine.

370
00:19:18,800 --> 00:19:21,840
Head of R&D here is
Dr Mene Pangalos.

371
00:19:23,200 --> 00:19:26,280
We're talking, for the AstraZeneca
vaccine,

372
00:19:26,280 --> 00:19:28,200
of potentially up to three billion
doses,

373
00:19:28,200 --> 00:19:31,480
or as close to that as we can get
in 2021.

374
00:19:33,360 --> 00:19:38,560
The manufacturers are all
manufacturing at a scale

375
00:19:38,560 --> 00:19:42,640
that they've never done before
in their histories.

376
00:19:46,080 --> 00:19:51,080
Another crucial benefit to using
genetically engineered vaccines

377
00:19:51,080 --> 00:19:55,000
is that there are new variants of
Covid involving the whole time,

378
00:19:55,000 --> 00:19:58,080
and they may be able to circumvent
the vaccines

379
00:19:58,080 --> 00:20:00,040
that we're currently using.

380
00:20:00,040 --> 00:20:02,800
The one that we're most concerned
about at the moment

381
00:20:02,800 --> 00:20:05,400
is the variant associated
with South Africa.

382
00:20:07,480 --> 00:20:10,840
And as we see this spike protein
mutating and changing,

383
00:20:10,840 --> 00:20:14,640
we can very quickly adapt
the sequence in the vaccine

384
00:20:14,640 --> 00:20:17,280
to adapt to those new variants.

385
00:20:17,280 --> 00:20:19,280
And that's a big advantage
for these platforms,

386
00:20:19,280 --> 00:20:22,680
because, as these variants appear,
we can start to get

387
00:20:22,680 --> 00:20:25,000
those new versions of the vaccines
out into the population

388
00:20:25,000 --> 00:20:26,320
as quickly as possible.

389
00:20:28,360 --> 00:20:32,000
A new-generation vaccine for a
dangerous variant of Covid

390
00:20:32,000 --> 00:20:33,600
will be rapid to produce

391
00:20:33,600 --> 00:20:36,640
because the genetic information
for the mutant spike protein

392
00:20:36,640 --> 00:20:38,800
can simply be slotted into
the vector.

393
00:20:41,040 --> 00:20:44,360
So they should be available
in months rather than years.

394
00:20:49,840 --> 00:20:53,520
I'm an infection doctor and I study
viruses in the lab,

395
00:20:53,520 --> 00:20:55,160
and even for me,

396
00:20:55,160 --> 00:20:58,360
the technology that's being
developed and now manufactured

397
00:20:58,360 --> 00:21:01,960
in this building feels
totally extraordinary.

398
00:21:01,960 --> 00:21:06,160
Brand-new, the beginning
of a new era in the way

399
00:21:06,160 --> 00:21:08,480
that we prevent infections
around the world.

400
00:21:13,640 --> 00:21:16,160
Professor Eleanor Riley
is an immunologist

401
00:21:16,160 --> 00:21:18,120
from the University of Edinburgh.

402
00:21:18,120 --> 00:21:20,040
Eleanor, it's very nice
to speak to you.

403
00:21:21,200 --> 00:21:22,560
The mutations -

404
00:21:22,560 --> 00:21:25,400
if we didn't update our vaccines,

405
00:21:25,400 --> 00:21:30,520
would mutations and new variants
eventually render them useless?

406
00:21:30,520 --> 00:21:34,720
I think we don't yet know
how much capacity there is

407
00:21:34,720 --> 00:21:37,200
in this virus to keep mutating.

408
00:21:37,200 --> 00:21:40,400
So we know,
for viruses like flu and HIV,

409
00:21:40,400 --> 00:21:43,280
they have an almost infinite
capacity to mutate,

410
00:21:43,280 --> 00:21:45,720
to change and still to infect us.

411
00:21:45,720 --> 00:21:50,000
I think, with this virus,
we don't know how much flex

412
00:21:50,000 --> 00:21:52,760
there is in the virus to
keep mutating

413
00:21:52,760 --> 00:21:54,640
and still be infectious.

414
00:21:54,640 --> 00:21:58,360
And I think, until we know that,
it's very difficult to know

415
00:21:58,360 --> 00:22:01,160
how far this virus might mutate,

416
00:22:01,160 --> 00:22:03,760
how far it might escape
the vaccines,

417
00:22:03,760 --> 00:22:07,040
and therefore how much we're going
to have to adapt the vaccines

418
00:22:07,040 --> 00:22:08,480
to keep up with it.

419
00:22:08,480 --> 00:22:11,360
OK, so we're just seeing
these new variants

420
00:22:11,360 --> 00:22:13,560
because this is the first time
it's spread

421
00:22:13,560 --> 00:22:15,360
throughout the human population.

422
00:22:15,360 --> 00:22:18,640
Yeah, we're watching this virus
evolve in real time.

423
00:22:18,640 --> 00:22:22,120
All the sequencing that we're
getting is showing us how,

424
00:22:22,120 --> 00:22:25,960
step by step, this is changing
from an animal coronavirus -

425
00:22:25,960 --> 00:22:27,760
and we don't quite know
which animal -

426
00:22:27,760 --> 00:22:29,560
into a human coronavirus,

427
00:22:29,560 --> 00:22:32,640
one that is a much better fit
for our cells.

428
00:22:32,640 --> 00:22:35,720
And in a way, my feeling is we just
need to let the virus

429
00:22:35,720 --> 00:22:39,000
settle down a little bit,
find out what is the best fit,

430
00:22:39,000 --> 00:22:42,200
and then see if it keeps on mutating
after that.

431
00:22:42,200 --> 00:22:44,840
Do you think we're likely to get
into a scenario

432
00:22:44,840 --> 00:22:47,080
a little bit like we have with flu,

433
00:22:47,080 --> 00:22:50,240
where we decide,
as the scientific community,

434
00:22:50,240 --> 00:22:54,800
what sequences we're going to plug
into that year's vaccines

435
00:22:54,800 --> 00:22:58,160
and there'll be an annual
or biannual update?

436
00:22:58,160 --> 00:23:01,320
I think, if that's the system
we end up with,

437
00:23:01,320 --> 00:23:04,560
I think it wouldn't be
an absolute disaster.

438
00:23:04,560 --> 00:23:07,200
But it's not just whether the virus
mutates,

439
00:23:07,200 --> 00:23:10,240
it's how long the vaccines
protect you for.

440
00:23:10,240 --> 00:23:13,280
And do they protect you against
severe disease and death

441
00:23:13,280 --> 00:23:17,560
for a long time, even if you might
actually get a mild

442
00:23:17,560 --> 00:23:20,640
or an asymptomatic infection
and be able to transmit it?

443
00:23:20,640 --> 00:23:24,960
I think it's quite possible that the
vaccines may protect against

444
00:23:24,960 --> 00:23:27,920
severe disease and death
for much longer

445
00:23:27,920 --> 00:23:31,160
than they protect against infection
and transmission.

446
00:23:31,160 --> 00:23:34,800
There's been a big discussion
about the interval

447
00:23:34,800 --> 00:23:36,720
between the first and
the second dose.

448
00:23:36,720 --> 00:23:38,880
And in general with vaccines,

449
00:23:38,880 --> 00:23:42,640
leaving an interval beyond
three weeks does allow

450
00:23:42,640 --> 00:23:44,760
an increased immune response

451
00:23:44,760 --> 00:23:47,600
compared to a very short interval,
is that right?

452
00:23:47,600 --> 00:23:49,440
Not necessarily increased,

453
00:23:49,440 --> 00:23:52,280
but it seems, certainly with some
other vaccines,

454
00:23:52,280 --> 00:23:55,520
to induce an immune response
of higher quality.

455
00:23:56,760 --> 00:23:59,600
So when you have your first dose
of vaccine,

456
00:23:59,600 --> 00:24:02,440
you activate a whole range
of immune cells,

457
00:24:02,440 --> 00:24:05,080
some of which, quite frankly,
are better

458
00:24:05,080 --> 00:24:06,920
at doing the job than others.

459
00:24:06,920 --> 00:24:10,160
And if you go back and boost
within three or four weeks,

460
00:24:10,160 --> 00:24:11,840
you boost all of those cells.

461
00:24:11,840 --> 00:24:17,240
But if you wait 8 to 12 weeks,
some of the not-so-good cells

462
00:24:17,240 --> 00:24:18,960
tend to die out.

463
00:24:18,960 --> 00:24:21,560
And so when you go back in,
you only tend to boost

464
00:24:21,560 --> 00:24:23,360
the very high-quality cells,

465
00:24:23,360 --> 00:24:26,600
and that means at the end
of that process, you've got

466
00:24:26,600 --> 00:24:30,440
a much higher-quality response
than if you went in earlier.

467
00:24:30,440 --> 00:24:34,680
But you're always balancing
what is the risk of waiting longer

468
00:24:34,680 --> 00:24:38,200
if you haven't got a full immune
response versus the benefits

469
00:24:38,200 --> 00:24:40,120
of waiting longer.

470
00:24:40,120 --> 00:24:43,520
What's the future for this virus
in terms of eradication?

471
00:24:43,520 --> 00:24:46,120
Some people are saying
that might be possible.

472
00:24:46,120 --> 00:24:48,320
The virus is on a bit
of a tightrope.

473
00:24:48,320 --> 00:24:52,920
If it changes enough to avoid
antibody response,

474
00:24:52,920 --> 00:24:57,320
it may no longer be able to bind
to the receptor on our cells.

475
00:24:57,320 --> 00:25:02,160
So really what we're trying to
understand is how much tolerance

476
00:25:02,160 --> 00:25:07,160
there is in the virus being able
to be still infectious and yet

477
00:25:07,160 --> 00:25:10,280
still mutate to avoid
our immune system.

478
00:25:10,280 --> 00:25:15,360
And I think we don't yet know
where those levels of tolerance are.

479
00:25:15,360 --> 00:25:17,680
OK, so that's the trade-off.

480
00:25:17,680 --> 00:25:21,280
A mutation that completely avoids
the immune system is of no use

481
00:25:21,280 --> 00:25:23,720
if that mutation
in the spike protein

482
00:25:23,720 --> 00:25:26,640
means it can't bind to our cells.
Exactly.

483
00:25:26,640 --> 00:25:28,320
That makes sense.

484
00:25:34,640 --> 00:25:38,120
We hope the vaccination will prove
to be a decisive weapon

485
00:25:38,120 --> 00:25:40,160
in our fight against coronavirus.

486
00:25:40,160 --> 00:25:43,200
But until that point, understanding
how the virus spreads

487
00:25:43,200 --> 00:25:45,600
around the country is vital
if we are to keep

488
00:25:45,600 --> 00:25:47,840
infections under control.

489
00:25:47,840 --> 00:25:51,880
Dr Guddi Singh is on the trail
of an airborne mystery.

490
00:25:56,360 --> 00:26:00,640
In the summer of 2020,
an international flight carrying

491
00:26:00,640 --> 00:26:03,680
49 passengers landed in Ireland.

492
00:26:03,680 --> 00:26:06,240
What no-one knew at the time

493
00:26:06,240 --> 00:26:09,600
was that 13 of those passengers
would later test positive

494
00:26:09,600 --> 00:26:11,400
for Covid-19.

495
00:26:13,440 --> 00:26:17,560
What happened next is documented
in this academic paper.

496
00:26:17,560 --> 00:26:21,560
It reveals how the virus spreads
through the population

497
00:26:21,560 --> 00:26:25,640
and highlights an often overlooked
factor which could help us

498
00:26:25,640 --> 00:26:29,880
to get on top of the spread of
Covid-19 and keep it that way.

499
00:26:33,160 --> 00:26:36,440
From the very beginning
of the pandemic, air travel helped

500
00:26:36,440 --> 00:26:39,880
the virus spread quickly
around the world, and scientists

501
00:26:39,880 --> 00:26:43,440
relied on mathematical models
to understand the dynamics

502
00:26:43,440 --> 00:26:45,840
of coronavirus transmission.

503
00:26:45,840 --> 00:26:50,400
By now, we've probably all heard
of R, the reproduction number,

504
00:26:50,400 --> 00:26:53,480
which represents the number
of people one infected person

505
00:26:53,480 --> 00:26:55,280
will pass the virus onto.

506
00:26:58,320 --> 00:27:03,040
The baseline reproduction number
for Covid-19 is around three,

507
00:27:03,040 --> 00:27:07,080
which means that without any control
measures in place, one infected

508
00:27:07,080 --> 00:27:11,080
person will infect three others
who will go on to infect

509
00:27:11,080 --> 00:27:14,080
three more and so on.

510
00:27:14,080 --> 00:27:17,040
But the R number is just an average.

511
00:27:17,040 --> 00:27:20,680
It explains what happens
in a whole population.

512
00:27:20,680 --> 00:27:25,360
It tells us nothing about
what happens to individuals.

513
00:27:25,360 --> 00:27:28,760
When scientists investigated
the Irish flight outbreak,

514
00:27:28,760 --> 00:27:33,520
a combination of contact tracing,
testing and DNA sequencing revealed

515
00:27:33,520 --> 00:27:36,120
something very different
to what the R number

516
00:27:36,120 --> 00:27:37,640
would have predicted.

517
00:27:39,560 --> 00:27:43,000
Most of the infected passengers
hadn't passed the disease on

518
00:27:43,000 --> 00:27:47,560
to anyone else, either during
or after the flight.

519
00:27:47,560 --> 00:27:52,440
Instead, all of the onward
transmission, 43 cases,

520
00:27:52,440 --> 00:27:55,160
stemmed from just five passengers.

521
00:27:57,080 --> 00:28:01,520
This is anything but the even
distribution the R number suggests.

522
00:28:02,680 --> 00:28:06,480
So, as well as R, epidemiologists
use another key measurement

523
00:28:06,480 --> 00:28:10,200
of transmission,
the lesser-known K factor.

524
00:28:16,560 --> 00:28:21,440
The K number describes how much
the disease clusters, it measures

525
00:28:21,440 --> 00:28:25,120
the difference in how many people
each person with coronavirus

526
00:28:25,120 --> 00:28:28,120
infects, and it shows us
how much of the spread

527
00:28:28,120 --> 00:28:30,760
is down to the super-spreading few.

528
00:28:38,280 --> 00:28:41,400
By analysing outbreaks
like the one in Ireland,

529
00:28:41,400 --> 00:28:44,800
scientists have calculated
the K number for Covid-19.

530
00:28:46,840 --> 00:28:50,960
A small K number means that
most of the transmission is caused

531
00:28:50,960 --> 00:28:55,760
by a small number of people,
while a large K number means every

532
00:28:55,760 --> 00:28:58,920
infected person contributes
roughly the same to the spread

533
00:28:58,920 --> 00:29:00,200
of the disease.

534
00:29:04,320 --> 00:29:09,160
Covid-19 has one of the lowest
K numbers of any infectious disease,

535
00:29:09,160 --> 00:29:12,720
and it means that as few
as 10% of infected people

536
00:29:12,720 --> 00:29:16,680
may be responsible for as much
as 90% of all transmission.

537
00:29:19,320 --> 00:29:22,920
But infected people are
very difficult to study.

538
00:29:22,920 --> 00:29:26,160
So to try to get a handle
on the phenomenon, super-spreading

539
00:29:26,160 --> 00:29:29,240
expert Mark Woolhouse examined pigs.

540
00:29:35,200 --> 00:29:39,000
And we found that some pigs simply
produce more virus than others.

541
00:29:39,000 --> 00:29:42,080
Some pigs actually didn't infect
any other pigs at all.

542
00:29:42,080 --> 00:29:44,840
Others were capable of infecting
four, five or six other pigs,

543
00:29:44,840 --> 00:29:47,640
so there was a very big variation
in how much infectivity

544
00:29:47,640 --> 00:29:49,960
there were
in these different animals.

545
00:29:49,960 --> 00:29:53,240
And so, do we know yet if there is
anything that is biologically

546
00:29:53,240 --> 00:29:56,480
different, that means that people
become super-spreaders?

547
00:29:56,480 --> 00:29:59,320
Well, that's the absolute
key question.

548
00:30:00,560 --> 00:30:04,840
The research is ongoing and
differences in our individual

549
00:30:04,840 --> 00:30:09,160
biology, like the thickness of our
saliva, how violently we cough

550
00:30:09,160 --> 00:30:12,960
or even how loudly we talk
may play a part.

551
00:30:14,760 --> 00:30:17,800
But what's more likely
to be a factor is the stage

552
00:30:17,800 --> 00:30:20,840
of our infection when we meet
another person.

553
00:30:20,840 --> 00:30:25,240
So the most infectious period is
typically the 24 hours either side

554
00:30:25,240 --> 00:30:26,960
of first showing symptoms.

555
00:30:26,960 --> 00:30:30,520
Viral load is high in the upper
respiratory tract at that time,

556
00:30:30,520 --> 00:30:33,280
so there's every possibility
that a person will be highly

557
00:30:33,280 --> 00:30:36,080
infectious at that stage
of the infection.

558
00:30:36,080 --> 00:30:40,360
For epidemiologists like Mark,
it's all about where these infected

559
00:30:40,360 --> 00:30:43,760
people are and what they're doing.

560
00:30:43,760 --> 00:30:48,080
In any case, the individual's
contribution to this only

561
00:30:48,080 --> 00:30:53,040
materialises if they are making
contacts, if they're in a setting

562
00:30:53,040 --> 00:30:55,000
where transmission is possible.

563
00:30:55,000 --> 00:30:58,200
So it is about the epidemiological
context of this.

564
00:30:58,200 --> 00:31:01,680
And so for that reason, I prefer not
to talk about super-spreaders,

565
00:31:01,680 --> 00:31:04,400
but I prefer to talk about
super-spreading events.

566
00:31:12,960 --> 00:31:16,120
A low K number could work
in our favour.

567
00:31:16,120 --> 00:31:20,960
If we can identify and target areas
of high risk for super-spreading,

568
00:31:20,960 --> 00:31:23,240
it should be easier to prevent.

569
00:31:23,240 --> 00:31:27,280
And because not everyone transmits
the virus, it should be harder

570
00:31:27,280 --> 00:31:29,520
for an outbreak to take off.

571
00:31:33,400 --> 00:31:37,040
I'm meeting Dr Adam Kucharski
from the London School of Hygiene

572
00:31:37,040 --> 00:31:39,080
and Tropical Medicine.

573
00:31:39,080 --> 00:31:40,760
Hi, Adam.
Hi, how are you?

574
00:31:43,760 --> 00:31:47,680
Look, we know that super-spreading
events happen, but is there anything

575
00:31:47,680 --> 00:31:51,040
that we can do to try and stop
or isolate them at all?

576
00:31:51,040 --> 00:31:54,920
So, one thing that can really help
is how we structure contact tracing,

577
00:31:54,920 --> 00:31:56,960
incorporating that knowledge
of super-spreading

578
00:31:56,960 --> 00:31:59,000
into how we approach that.

579
00:31:59,000 --> 00:32:01,520
So can you just explain to me
how contact tracing works?

580
00:32:01,520 --> 00:32:03,040
So there's two components to it.

581
00:32:03,040 --> 00:32:06,000
I think all of us are familiar
with the basic idea of contact

582
00:32:06,000 --> 00:32:09,520
tracing, what we call forward
tracing, where if you have a new

583
00:32:09,520 --> 00:32:12,560
case appear, someone with
symptoms gets tested,

584
00:32:12,560 --> 00:32:14,440
has come down with Covid,

585
00:32:14,440 --> 00:32:17,040
you look at all the people
that they've come into contact with

586
00:32:17,040 --> 00:32:18,680
and they potentially
might have infected,

587
00:32:18,680 --> 00:32:20,520
then you quarantine those people.

588
00:32:20,520 --> 00:32:22,960
And so if one of them turns out
to have been infected,

589
00:32:22,960 --> 00:32:25,360
they can't then go on
to infect others.

590
00:32:25,360 --> 00:32:27,800
This is called forward tracing.

591
00:32:27,800 --> 00:32:32,200
But in countries like Japan and
South Korea, they also routinely

592
00:32:32,200 --> 00:32:36,560
work backwards to see if they can
uncover these clusters of infection

593
00:32:36,560 --> 00:32:38,400
and stop further transmission.

594
00:32:40,400 --> 00:32:44,320
So if you go backwards and
look at the events that initially

595
00:32:44,320 --> 00:32:47,520
infected them, that's likely
to be a super-spreading event,

596
00:32:47,520 --> 00:32:50,960
which means that there's probably
quite a few other people

597
00:32:50,960 --> 00:32:54,520
who were infected at this event
who might not know it.

598
00:32:54,520 --> 00:32:59,440
The theory is that the person
who gave you the virus will also

599
00:32:59,440 --> 00:33:02,160
have infected other people.

600
00:33:02,160 --> 00:33:06,440
So by looking back, we'll soon get
to the source of the outbreak,

601
00:33:06,440 --> 00:33:09,440
the super-spreading event,

602
00:33:09,440 --> 00:33:12,120
and uncover
previously undetected cases.

603
00:33:13,120 --> 00:33:17,160
So do we know what added benefit
backwards tracing actually adds?

604
00:33:17,160 --> 00:33:20,240
Yes, we've estimated in some
modelling that in the two weeks

605
00:33:20,240 --> 00:33:23,880
after one of these initial cases
appears, if you add backward tracing

606
00:33:23,880 --> 00:33:26,920
on top of forward tracing, you
can potentially double the number

607
00:33:26,920 --> 00:33:29,160
of onward transmission events
that you prevent.

608
00:33:32,320 --> 00:33:36,800
Covid-19 is an insidious
and unpredictable disease

609
00:33:36,800 --> 00:33:40,320
because hidden super-spreading
events play such an important role

610
00:33:40,320 --> 00:33:42,480
in its transmission.

611
00:33:42,480 --> 00:33:46,200
But understanding K
is only half the battle.

612
00:33:46,200 --> 00:33:49,920
One of our best hopes for dealing
with this disease is implementing

613
00:33:49,920 --> 00:33:53,560
our knowledge and with fast
and effective contact tracing

614
00:33:53,560 --> 00:33:58,600
to catch cases and clusters
before they have a chance to spread.

615
00:34:04,720 --> 00:34:07,760
It was recently announced
that a surge in testing

616
00:34:07,760 --> 00:34:11,000
is going to be introduced
to try to help us all get back

617
00:34:11,000 --> 00:34:13,240
to a more normal way of life.

618
00:34:13,240 --> 00:34:17,720
Up to 400,000 lateral flow tests
are planned

619
00:34:17,720 --> 00:34:19,680
to be distributed every day.

620
00:34:19,680 --> 00:34:22,640
So it looks as though testing
is going to become a big part

621
00:34:22,640 --> 00:34:25,560
of all of our lives as we start
to go back to work,

622
00:34:25,560 --> 00:34:28,960
go back to school
and to travel with more freedom.

623
00:34:28,960 --> 00:34:31,640
Now, there are two main types
of test.

624
00:34:31,640 --> 00:34:34,840
There's the polymerase chain
reaction or the PCR test,

625
00:34:34,840 --> 00:34:37,400
and there's a lateral flow test.

626
00:34:37,400 --> 00:34:40,680
Both tests analyse samples
of mucus taken from the nose

627
00:34:40,680 --> 00:34:42,080
or from the throat.

628
00:34:42,080 --> 00:34:46,560
The PCR test looks for fragments
of the virus's genetic material.

629
00:34:46,560 --> 00:34:49,400
It generally needs to be sent
to a lab.

630
00:34:49,400 --> 00:34:52,120
This is a lateral flow test.

631
00:34:52,120 --> 00:34:55,080
It can give you a result
in a matter of minutes.

632
00:34:55,080 --> 00:34:57,720
Now, both tests,
PCR and lateral flow,

633
00:34:57,720 --> 00:35:00,800
either give you a positive result
or a negative result,

634
00:35:00,800 --> 00:35:02,640
but it's vitally important

635
00:35:02,640 --> 00:35:06,600
that everyone understands
what that actually means.

636
00:35:06,600 --> 00:35:11,160
Now, this graph shows an important
difference between the two tests.

637
00:35:11,160 --> 00:35:15,400
There's time on the X axis,
viral level on the Y axis

638
00:35:15,400 --> 00:35:18,760
and the white line is the level of
infection in the body

639
00:35:18,760 --> 00:35:20,480
and the grey shading
in the middle

640
00:35:20,480 --> 00:35:21,640
is the period of time

641
00:35:21,640 --> 00:35:24,600
when you are likely to be infectious
to other people.

642
00:35:24,600 --> 00:35:26,760
Now, the lateral flow test

643
00:35:26,760 --> 00:35:28,720
is only able to detect virus

644
00:35:28,720 --> 00:35:30,360
in this period here,

645
00:35:30,360 --> 00:35:36,320
whilst the PCR test can detect
virus both earlier and for longer.

646
00:35:36,320 --> 00:35:39,320
But what's also really clear
from this graph

647
00:35:39,320 --> 00:35:40,760
is that there is a blind spot

648
00:35:40,760 --> 00:35:42,400
for both tests at the beginning.

649
00:35:42,400 --> 00:35:45,080
It's possible to get
a negative result

650
00:35:45,080 --> 00:35:47,880
even if you've been infected
already.

651
00:35:47,880 --> 00:35:51,840
So both tests only tell you
about whether you are positive

652
00:35:51,840 --> 00:35:54,240
at the moment they are done.

653
00:35:54,240 --> 00:35:57,960
You might become infectious days,
hours, even minutes later.

654
00:35:57,960 --> 00:36:00,880
But there is an additional thing
that everyone needs to understand

655
00:36:00,880 --> 00:36:03,120
about the lateral flow test.

656
00:36:03,120 --> 00:36:05,160
When you get a positive result,

657
00:36:05,160 --> 00:36:07,480
you are very likely to be
infectious.

658
00:36:07,480 --> 00:36:10,480
You must isolate
and stop spreading the virus.

659
00:36:10,480 --> 00:36:14,160
But these tests miss a significant
number of Covid cases

660
00:36:14,160 --> 00:36:16,280
when used in the real world.

661
00:36:16,280 --> 00:36:19,600
And what this means is
that if you have a negative result

662
00:36:19,600 --> 00:36:23,600
from a lateral flow test, you may
still be positive, even infectious.

663
00:36:23,600 --> 00:36:26,080
So you have to keep acting,
as we all are,

664
00:36:26,080 --> 00:36:27,800
as if you might be infectious,

665
00:36:27,800 --> 00:36:29,520
even if you feel well.

666
00:36:29,520 --> 00:36:32,240
So a positive result should be taken
seriously.

667
00:36:32,240 --> 00:36:36,240
A negative result means you should
not change your behaviour at all.

668
00:36:39,000 --> 00:36:41,720
Testing individuals can be
time-consuming

669
00:36:41,720 --> 00:36:44,600
when we have so many people to test.

670
00:36:44,600 --> 00:36:47,600
One ingenious way of gathering
more data

671
00:36:47,600 --> 00:36:49,520
is being trialled at the moment -

672
00:36:49,520 --> 00:36:52,400
the continuous sampling
of our sewers.

673
00:36:52,400 --> 00:36:55,520
When someone has an infection,
billions of virus fragments

674
00:36:55,520 --> 00:36:57,640
are shed in their urine and faeces,

675
00:36:57,640 --> 00:37:00,440
and these get washed
into the sewers.

676
00:37:00,440 --> 00:37:03,480
So the plan is that if a particular
treatment station

677
00:37:03,480 --> 00:37:05,000
sees a surge in levels,

678
00:37:05,000 --> 00:37:08,280
they can alert the local authority
to respond rapidly

679
00:37:08,280 --> 00:37:12,560
with a targeted testing programme
and hopefully stifle any outbreak.

680
00:37:17,480 --> 00:37:19,320
Currently,
the numbers are telling us

681
00:37:19,320 --> 00:37:21,760
that while we are some way off
the end of the pandemic,

682
00:37:21,760 --> 00:37:24,760
thankfully we do seem to be coming
out of the second wave,

683
00:37:24,760 --> 00:37:26,320
and there's more good news.

684
00:37:26,320 --> 00:37:28,520
Statistics on hospital treatment

685
00:37:28,520 --> 00:37:31,920
show that tiny changes can add up
to big wins.

686
00:37:31,920 --> 00:37:34,800
And they give us another reason
for cautious optimism.

687
00:37:43,080 --> 00:37:46,160
Incredibly, the risk of dying
in hospital from Covid

688
00:37:46,160 --> 00:37:47,960
has more than halved,

689
00:37:47,960 --> 00:37:51,200
falling from 35% to around 15%.

690
00:37:56,280 --> 00:37:58,280
These amazing improvements

691
00:37:58,280 --> 00:38:01,120
are, in part, thanks to a number
of treatments

692
00:38:01,120 --> 00:38:03,960
that on their own might seem
insignificant.

693
00:38:03,960 --> 00:38:06,400
Put together, they make a big
difference.

694
00:38:08,480 --> 00:38:11,040
You know, a year ago,
this was an unknown disease.

695
00:38:11,040 --> 00:38:14,800
Much of what we were doing
was educated guesswork.

696
00:38:14,800 --> 00:38:18,000
But within just a year,
we have figured out so much

697
00:38:18,000 --> 00:38:21,080
about how to treat
patients with this disease.

698
00:38:22,120 --> 00:38:25,920
This is University College Hospital
in London, where I work,

699
00:38:25,920 --> 00:38:30,200
and where my colleague, infectious
diseases consultant Dr Sarah Logan,

700
00:38:30,200 --> 00:38:33,640
has been battling the disease
from the beginning.

701
00:38:36,120 --> 00:38:38,520
A decision whether someone needs
to come into a hospital

702
00:38:38,520 --> 00:38:41,960
is around whether someone needs
support for their breathing. OK.

703
00:38:41,960 --> 00:38:45,040
And sometimes we need to give them
a mask of oxygen.

704
00:38:47,480 --> 00:38:49,120
At the start of the pandemic,

705
00:38:49,120 --> 00:38:51,560
far more patients were put
on ventilators -

706
00:38:51,560 --> 00:38:53,960
an invasive procedure
needing sedation

707
00:38:53,960 --> 00:38:56,880
and a breathing tube inserted
down the throat.

708
00:38:56,880 --> 00:38:58,640
But now that's changed.

709
00:38:59,680 --> 00:39:02,320
A type of breathing support
called CPAP -

710
00:39:02,320 --> 00:39:04,920
continuous positive airways
pressure -

711
00:39:04,920 --> 00:39:08,360
can prevent the need
for such invasive ventilation.

712
00:39:10,200 --> 00:39:12,640
There's a tube going to a machine

713
00:39:12,640 --> 00:39:16,920
that is blowing oxygenated air
hard at the face.

714
00:39:16,920 --> 00:39:19,560
And what that means is, the air
is forced down into the lungs

715
00:39:19,560 --> 00:39:21,560
and it slightly inflates them.

716
00:39:21,560 --> 00:39:23,200
And that has two effects -

717
00:39:23,200 --> 00:39:25,360
it pushes oxygen into the body,

718
00:39:25,360 --> 00:39:29,240
but it also pushes fluid out of the
lung tissue and keeps it inflated.

719
00:39:31,960 --> 00:39:33,680
A study in the north of England

720
00:39:33,680 --> 00:39:37,760
showed that using CPAP early
in the treatment of some patients

721
00:39:37,760 --> 00:39:39,440
may also increase survival.

722
00:39:40,960 --> 00:39:42,720
Of course, the sickest patients

723
00:39:42,720 --> 00:39:44,960
will still need to go
on intensive care,

724
00:39:44,960 --> 00:39:48,800
where more remarkable discoveries
are making a huge difference.

725
00:39:51,840 --> 00:39:55,720
Mark Vargas is a senior
critical care charge nurse.

726
00:40:00,640 --> 00:40:02,000
Let's get ready.

727
00:40:02,000 --> 00:40:03,960
You've aspirated...?

728
00:40:05,920 --> 00:40:07,560
Mark and his colleagues have found

729
00:40:07,560 --> 00:40:11,320
that lying critically ill patients
on their stomachs, or proning,

730
00:40:11,320 --> 00:40:15,040
has made a significant difference
to survival rates.

731
00:40:15,040 --> 00:40:17,880
A proning team consists
of six people,

732
00:40:17,880 --> 00:40:19,920
with one leading the team

733
00:40:19,920 --> 00:40:22,160
and one holding the airway on top.

734
00:40:22,160 --> 00:40:27,000
Before Covid, we'd do this
maybe two or three times in a year.

735
00:40:27,000 --> 00:40:29,400
Oh, really? OK. Yeah.
Now you're proning

736
00:40:29,400 --> 00:40:31,480
three patients daily in one room.

737
00:40:31,480 --> 00:40:34,920
Daily, yeah, and there's more to be
proned in the other bays. Really?

738
00:40:38,360 --> 00:40:42,240
Proning patients like this can
pull out their breathing tubes.

739
00:40:42,240 --> 00:40:45,320
The expert team must take
exceptional care.

740
00:40:48,960 --> 00:40:51,200
Proning seems to help the
sickest patients

741
00:40:51,200 --> 00:40:53,560
because lying on their back
all the time

742
00:40:53,560 --> 00:40:56,240
can make fluid build up
in the rear of the lungs

743
00:40:56,240 --> 00:40:59,280
and they can be compressed
by other organs.

744
00:41:00,280 --> 00:41:02,960
Putting patients on their stomachs
can relieve this

745
00:41:02,960 --> 00:41:06,000
and allow better oxygenation
of the blood.

746
00:41:06,000 --> 00:41:07,920
I mean, there's such skill,

747
00:41:07,920 --> 00:41:10,680
but that is such a risky thing to
do to a patient

748
00:41:10,680 --> 00:41:12,880
if you don't know
exactly what you're doing.

749
00:41:12,880 --> 00:41:14,240
And watching that,

750
00:41:14,240 --> 00:41:17,760
that for me is the pinnacle
of what goes on here.

751
00:41:19,120 --> 00:41:22,880
Recovery rates in ICU have
greatly improved.

752
00:41:22,880 --> 00:41:25,720
In one study, survival improved

753
00:41:25,720 --> 00:41:27,480
from 58% in March 2020

754
00:41:27,480 --> 00:41:29,160
to over 80%

755
00:41:29,160 --> 00:41:30,960
in June of the same year.

756
00:41:32,240 --> 00:41:36,480
Part of that improvement is thanks
to the advances in nursing care.

757
00:41:36,480 --> 00:41:39,160
And some of it is because of
a greater understanding

758
00:41:39,160 --> 00:41:42,400
of how to treat the disease
with medicines.

759
00:41:42,400 --> 00:41:45,640
The steroid dexamethasone
has been used for decades.

760
00:41:45,640 --> 00:41:48,160
It broadly suppresses the
immune system

761
00:41:48,160 --> 00:41:52,720
and it can reduce the overall risk
of death from Covid by up to 17%,

762
00:41:52,720 --> 00:41:56,480
chiefly benefiting
those patients on oxygen.

763
00:41:56,480 --> 00:41:59,480
Another anti-inflammatory used
to treat arthritis

764
00:41:59,480 --> 00:42:03,560
has recently been shown to prevent
one death in 25.

765
00:42:03,560 --> 00:42:05,640
It sounds like a small gain,

766
00:42:05,640 --> 00:42:09,600
but taken together with all
the other improvements in care,

767
00:42:09,600 --> 00:42:11,440
it makes a big difference.

768
00:42:11,440 --> 00:42:14,440
Has there been sort of one
giant leap,

769
00:42:14,440 --> 00:42:16,240
or is it lots of little changes?

770
00:42:16,240 --> 00:42:18,920
Without doubt,
it is little adjustments

771
00:42:18,920 --> 00:42:21,920
to lots of different things.

772
00:42:21,920 --> 00:42:24,400
I feel, with someone who I thought

773
00:42:24,400 --> 00:42:27,480
might not have survived
back in March,

774
00:42:27,480 --> 00:42:31,560
I feel we've got so many more tools
in our cupboard

775
00:42:31,560 --> 00:42:34,440
to help get them through it.

776
00:42:37,520 --> 00:42:40,640
The improvements in survival
with Covid-19 that we've seen

777
00:42:40,640 --> 00:42:42,560
over the last year are largely

778
00:42:42,560 --> 00:42:47,360
because we are optimising all the
different aspects of patient care,

779
00:42:47,360 --> 00:42:49,800
and that really is a tribute

780
00:42:49,800 --> 00:42:52,840
to every person that works
in this building.

781
00:42:52,840 --> 00:42:57,520
There's still an unfolding tragedy,
of course, but we are now able

782
00:42:57,520 --> 00:42:59,720
to save many, many more lives.

783
00:43:03,440 --> 00:43:06,280
We may be coming off the peak
of the second wave,

784
00:43:06,280 --> 00:43:08,880
but that means that many of us who
have had the infection

785
00:43:08,880 --> 00:43:10,920
might be worried about long Covid.

786
00:43:10,920 --> 00:43:13,960
It's one of the more surprising
and unwelcome things

787
00:43:13,960 --> 00:43:15,360
about this infection.

788
00:43:15,360 --> 00:43:18,400
I got Covid in April and it left
me with a heart arrhythmia

789
00:43:18,400 --> 00:43:22,160
and fatigue and exhaustion
for many months afterwards.

790
00:43:22,160 --> 00:43:27,560
Dr David Strain is the BMA's lead
on the NHS's long Covid task force.

791
00:43:27,560 --> 00:43:29,800
David, thank you very much
for coming in.

792
00:43:29,800 --> 00:43:33,280
Are my symptoms typical of the
kind of things that you're seeing?

793
00:43:33,280 --> 00:43:35,760
Your symptoms are very typical.

794
00:43:35,760 --> 00:43:39,720
We do see many patients who present
with these cardiac problems

795
00:43:39,720 --> 00:43:42,600
or with breathing problems
and then a fatigue.

796
00:43:42,600 --> 00:43:44,760
There's two real types of
long Covid.

797
00:43:44,760 --> 00:43:47,600
There's long Covid that can be
attributed

798
00:43:47,600 --> 00:43:50,240
to a really bad case of
Covid in the first instance,

799
00:43:50,240 --> 00:43:52,760
so they're the people who ended
up in ITU,

800
00:43:52,760 --> 00:43:55,720
they're the people who got
pulmonary scarring,

801
00:43:55,720 --> 00:43:57,560
they might have had small clots
in the brain

802
00:43:57,560 --> 00:43:58,880
or small clots in the body,

803
00:43:58,880 --> 00:44:01,920
and they've left them with long-term
consequences afterwards.

804
00:44:01,920 --> 00:44:05,160
But then the surprising group
that's come out of this

805
00:44:05,160 --> 00:44:07,080
is a group of individuals
like yourself

806
00:44:07,080 --> 00:44:09,600
who didn't get
particularly bad Covid,

807
00:44:09,600 --> 00:44:13,560
but we're getting many people
who, two to three months later,

808
00:44:13,560 --> 00:44:17,960
are still left with this chronic,
debilitating fatigue. Really?

809
00:44:17,960 --> 00:44:20,400
So even if you haven't been
in intensive care,

810
00:44:20,400 --> 00:44:22,880
you haven't been
severely short of breath,

811
00:44:22,880 --> 00:44:26,280
you haven't had that kind of
severe, immediate organ damage,

812
00:44:26,280 --> 00:44:29,720
you can still have very,
very protracted consequences?

813
00:44:29,720 --> 00:44:31,920
Absolutely. And if anything,

814
00:44:31,920 --> 00:44:35,640
we're seeing it more common
in the younger patients,

815
00:44:35,640 --> 00:44:37,840
the fitter, the very active,

816
00:44:37,840 --> 00:44:41,720
the ones who may have got over
the initial disease very quickly,

817
00:44:41,720 --> 00:44:45,560
but then have been left with these
long, debilitating symptoms.

818
00:44:45,560 --> 00:44:48,840
We've got some patients who caught
Covid back in March

819
00:44:48,840 --> 00:44:52,240
and still are not able
to function for a full day.

820
00:44:52,240 --> 00:44:54,320
What we think is happening is,

821
00:44:54,320 --> 00:44:56,960
the virus is affecting
the mitochondria of the cells.

822
00:44:56,960 --> 00:44:59,400
So, the mitochondria of the cells
are...effectively

823
00:44:59,400 --> 00:45:02,840
it's the battery that every single
cell has that keeps it charged,

824
00:45:02,840 --> 00:45:04,720
that keeps it able to do things.

825
00:45:04,720 --> 00:45:08,240
Long Covid is effectively like
having a run-down battery.

826
00:45:08,240 --> 00:45:09,840
We've all seen a smartphone

827
00:45:09,840 --> 00:45:12,800
that's had three or four years'
worth of use

828
00:45:12,800 --> 00:45:15,040
and it will die
in about 50 minutes

829
00:45:15,040 --> 00:45:17,040
after you take it off the charger.

830
00:45:17,040 --> 00:45:20,320
Long Covid leaves your cells
in exactly that same position.

831
00:45:20,320 --> 00:45:23,360
Just the walk to the kitchen,

832
00:45:23,360 --> 00:45:25,760
you'll start to feel tired
and exhausted.

833
00:45:25,760 --> 00:45:28,840
I definitely felt that. When I woke
up in the morning I'd think,

834
00:45:28,840 --> 00:45:31,720
"Great, I can attack the day.
This is going to be fine,"

835
00:45:31,720 --> 00:45:35,360
and I'd ride my bike to work and be
shattered by the time I got there,

836
00:45:35,360 --> 00:45:36,960
almost in tears, I was so tired.

837
00:45:36,960 --> 00:45:39,440
One of the key things
that we're recommending

838
00:45:39,440 --> 00:45:43,240
is that people
stay within their energy envelope.

839
00:45:43,240 --> 00:45:45,880
So if you know that you are going
to be exhausted

840
00:45:45,880 --> 00:45:50,280
after you walk a mile,
stop 200 yards short,

841
00:45:50,280 --> 00:45:53,680
sit down, rest,
let your battery recharge naturally.

842
00:45:53,680 --> 00:45:55,480
Is there anything you can do

843
00:45:55,480 --> 00:45:58,280
to reduce your chances
of having long Covid?

844
00:45:59,480 --> 00:46:01,120
One of the common features

845
00:46:01,120 --> 00:46:03,840
in our studies of people
who've got long Covid

846
00:46:03,840 --> 00:46:05,600
is that they're people who,

847
00:46:05,600 --> 00:46:09,640
when they caught it in the first
instance, tried to work through it.

848
00:46:09,640 --> 00:46:11,320
They tried to say,

849
00:46:11,320 --> 00:46:14,120
"Oh, it's only a mild disease,
I'll shrug it off, I'll get on."

850
00:46:14,120 --> 00:46:15,560
And the result is

851
00:46:15,560 --> 00:46:19,000
that they've been left with
much more lasting consequences.

852
00:46:19,000 --> 00:46:21,160
So the one piece of advice,
I would say,

853
00:46:21,160 --> 00:46:22,720
if anyone tests positive,

854
00:46:22,720 --> 00:46:26,920
if anyone's got even the mildest
symptoms, take it easy,

855
00:46:26,920 --> 00:46:28,160
go easy on yourself,

856
00:46:28,160 --> 00:46:30,680
because the more chance you
get to recover today

857
00:46:30,680 --> 00:46:35,720
means the better you will be over
the next few months and few years.

858
00:46:35,720 --> 00:46:38,480
This has perhaps been
underemphasised,

859
00:46:38,480 --> 00:46:41,400
how important it is, even if you
have a mild case of Covid,

860
00:46:41,400 --> 00:46:43,600
that you rest and take the time to
recuperate

861
00:46:43,600 --> 00:46:46,400
maybe much longer than you would
naturally be inclined to do.

862
00:46:46,400 --> 00:46:49,680
Yes. If you do catch Covid,
you need to take it easy.

863
00:46:49,680 --> 00:46:54,960
You need to sit back and relax
for two, maybe three or four weeks

864
00:46:54,960 --> 00:46:57,600
before you start trying to
re-engage and do things

865
00:46:57,600 --> 00:46:59,880
as you would normally
have done previously.

866
00:46:59,880 --> 00:47:02,320
Before this coronavirus came along,

867
00:47:02,320 --> 00:47:05,760
you had worked on chronic fatigue
syndrome, on ME,

868
00:47:05,760 --> 00:47:09,800
and other things that we sort of
associate with viral infections

869
00:47:09,800 --> 00:47:12,000
that affect people for a long time.

870
00:47:12,000 --> 00:47:13,840
Has the emergence of long Covid

871
00:47:13,840 --> 00:47:16,560
changed the landscape for people
with those conditions?

872
00:47:16,560 --> 00:47:18,960
It's a silver lining to this whole
outbreak

873
00:47:18,960 --> 00:47:22,800
that people who've been shouting
about ME and CFS

874
00:47:22,800 --> 00:47:25,920
for the last 20 years
are suddenly being heard.

875
00:47:25,920 --> 00:47:28,080
One of the studies that
we're planning on doing

876
00:47:28,080 --> 00:47:32,360
is going to be directly comparing
patients with long Covid,

877
00:47:32,360 --> 00:47:34,160
patients with chronic fatigue
syndrome,

878
00:47:34,160 --> 00:47:37,000
because we think there are going
to be some similarities.

879
00:47:37,000 --> 00:47:39,440
Now, the two main areas
that we're looking at

880
00:47:39,440 --> 00:47:41,000
are in the mitochondria,

881
00:47:41,000 --> 00:47:42,960
the batteries that we spoke about

882
00:47:42,960 --> 00:47:46,360
that we know are affected
by long Covid,

883
00:47:46,360 --> 00:47:48,560
and then the other place
that we're interested in

884
00:47:48,560 --> 00:47:51,400
is the microcirculation, the
smallest blood vessels,

885
00:47:51,400 --> 00:47:54,000
the ones that are responsible for
delivering the oxygen

886
00:47:54,000 --> 00:47:56,720
and the nutrients
and the hormones to your tissues.

887
00:47:56,720 --> 00:48:00,160
And the hope is that as we develop
a treatment for long Covid,

888
00:48:00,160 --> 00:48:01,600
that can then carry over

889
00:48:01,600 --> 00:48:05,280
and we can then start treating
these people who've had CFS or ME

890
00:48:05,280 --> 00:48:06,640
for the last 20 years

891
00:48:06,640 --> 00:48:11,560
and have been left with what is
a life-changing physical illness

892
00:48:11,560 --> 00:48:13,440
that they've struggled

893
00:48:13,440 --> 00:48:17,040
to even have accepted as a disease
in its own right.

894
00:48:17,040 --> 00:48:19,200
So interesting.
David, thank you very much.

895
00:48:21,200 --> 00:48:24,960
The story of Covid has so far
been full of twists and turns

896
00:48:24,960 --> 00:48:27,440
and has lasted longer
than any of us wanted.

897
00:48:27,440 --> 00:48:30,400
But so far, science has provided us
with an impressive armoury

898
00:48:30,400 --> 00:48:31,920
with which to fight the disease.

899
00:48:31,920 --> 00:48:34,280
Can it also provide an answer

900
00:48:34,280 --> 00:48:36,440
to the biggest question of all -

901
00:48:36,440 --> 00:48:38,920
when are we going to get
back to normal?

902
00:48:47,280 --> 00:48:49,720
This week, we've seen
the first potential

903
00:48:49,720 --> 00:48:52,800
timelines laid out for the
lifting of restrictions.

904
00:48:53,960 --> 00:48:56,840
But with so much
uncertainty still ahead,

905
00:48:56,840 --> 00:49:00,680
can we ever envisage a time when we
will be totally free of the virus?

906
00:49:05,000 --> 00:49:10,880
An answer to when that day might
come could lie in mathematics,

907
00:49:10,880 --> 00:49:13,680
and in this fairly simple formula.

908
00:49:14,960 --> 00:49:19,000
It's all about H,
the herd immunity threshold.

909
00:49:19,000 --> 00:49:22,440
That's the percentage of people
who must be immunised

910
00:49:22,440 --> 00:49:26,080
in the population to stop
the disease from spreading.

911
00:49:26,080 --> 00:49:27,880
And we can work that out

912
00:49:27,880 --> 00:49:30,400
if you know these two things -

913
00:49:30,400 --> 00:49:33,520
R0, the reproduction number,

914
00:49:33,520 --> 00:49:35,800
which is how easily
the virus spreads

915
00:49:35,800 --> 00:49:37,720
if there are no restrictions,

916
00:49:37,720 --> 00:49:43,760
and E, vaccine efficacy, a measure
of how well the vaccine is working.

917
00:49:45,000 --> 00:49:47,720
Let's plug in numbers
for coronavirus.

918
00:49:47,720 --> 00:49:50,480
We'll assume the baseline R0 is 3,

919
00:49:50,480 --> 00:49:53,120
and we'll use an average efficacy

920
00:49:53,120 --> 00:49:58,400
of the two vaccines currently
in use, around 79%.

921
00:49:58,400 --> 00:50:02,800
This gives a figure of 84%
of the population that need the jab

922
00:50:02,800 --> 00:50:06,760
to achieve herd immunity,
about 56 million people.

923
00:50:08,560 --> 00:50:12,160
Now, we've been immunising
2.5 million people a week,

924
00:50:12,160 --> 00:50:17,040
and at that rate we should reach
herd immunity by November 2021.

925
00:50:19,040 --> 00:50:21,320
But our figures make
huge assumptions

926
00:50:21,320 --> 00:50:24,600
that are tricky to pin down
in the real world.

927
00:50:24,600 --> 00:50:28,040
Let's leave the reproduction
number, R0, for the moment

928
00:50:28,040 --> 00:50:30,960
and turn our attention to efficacy.

929
00:50:30,960 --> 00:50:33,160
So efficacy is a measure

930
00:50:33,160 --> 00:50:36,560
of how well
a vaccine can protect a person

931
00:50:36,560 --> 00:50:39,120
from an infectious disease,
in this case Covid.

932
00:50:39,120 --> 00:50:44,680
If a vaccine in a clinical trial is
shown to have an efficacy of 50%,

933
00:50:44,680 --> 00:50:46,840
this roughly tells us

934
00:50:46,840 --> 00:50:50,480
that we can expect those people
who are vaccinated

935
00:50:50,480 --> 00:50:53,640
to have a 50% reduced risk of
becoming sick

936
00:50:53,640 --> 00:50:58,040
compared to an otherwise similar
unvaccinated group of people.

937
00:50:58,040 --> 00:51:00,160
So if I understand that correctly,

938
00:51:00,160 --> 00:51:02,000
it's not as though the vaccine

939
00:51:02,000 --> 00:51:04,840
just switches off our risk
of getting the disease,

940
00:51:04,840 --> 00:51:07,680
it's more that it reduces the risk
of us getting the disease,

941
00:51:07,680 --> 00:51:10,520
it kind of dials it down. Yes.

942
00:51:10,520 --> 00:51:14,760
What we now say
about the AstraZeneca vaccine

943
00:51:14,760 --> 00:51:17,200
is that it reduces disease.

944
00:51:17,200 --> 00:51:21,080
And what we've also seen is
it reduced hospitalisations,

945
00:51:21,080 --> 00:51:22,720
so how severe the disease is

946
00:51:22,720 --> 00:51:25,120
and whether you need to go
into hospital.

947
00:51:25,120 --> 00:51:29,800
However, the clinical trials that
were done for all the vaccines,

948
00:51:29,800 --> 00:51:33,280
or the majority of vaccines,
did not look at transmission,

949
00:51:33,280 --> 00:51:35,880
whether you can still
become infected,

950
00:51:35,880 --> 00:51:37,960
you don't get severe disease,

951
00:51:37,960 --> 00:51:40,560
but you could pass that infection
on to someone else.

952
00:51:42,600 --> 00:51:46,080
Early indications suggest
the AstraZeneca vaccine

953
00:51:46,080 --> 00:51:50,120
may reduce transmission
by around 67%,

954
00:51:50,120 --> 00:51:54,960
but more robust data
on all the vaccines is needed.

955
00:51:54,960 --> 00:51:59,680
Expressing vaccine efficacy
as a single exact figure like this

956
00:51:59,680 --> 00:52:01,080
is useful for illustration,

957
00:52:01,080 --> 00:52:05,120
but it's a little bit
simplistic for real life.

958
00:52:05,120 --> 00:52:08,000
It assumes that the vaccine protects
equally well

959
00:52:08,000 --> 00:52:09,840
against infection as disease

960
00:52:09,840 --> 00:52:13,080
and that the vaccines will be just
as effective in real life

961
00:52:13,080 --> 00:52:15,720
as they were in clinical trials.

962
00:52:16,920 --> 00:52:19,520
To get an idea of how even
a small reduction

963
00:52:19,520 --> 00:52:23,280
in the real-life vaccine
effectiveness affects our formula,

964
00:52:23,280 --> 00:52:26,280
let's see what happens if we reduce
the efficacy figure

965
00:52:26,280 --> 00:52:28,280
by just a couple of percent.

966
00:52:28,280 --> 00:52:32,560
So instead of our 79%,
let's use 77%.

967
00:52:36,600 --> 00:52:38,640
If we do that, what we'll see

968
00:52:38,640 --> 00:52:42,720
is that the percentage of people
who have to be immunised

969
00:52:42,720 --> 00:52:46,800
to reach herd immunity goes up
from 84%...

970
00:52:50,600 --> 00:52:52,040
..to 87%.

971
00:52:54,000 --> 00:52:55,960
And small changes matter.

972
00:52:55,960 --> 00:53:00,200
This could delay when we get back
to normal by weeks.

973
00:53:00,200 --> 00:53:04,640
And then, of course, there's R0,
the reproduction number.

974
00:53:04,640 --> 00:53:07,520
At the beginning of the pandemic,

975
00:53:07,520 --> 00:53:10,120
scientists thought one
infected person

976
00:53:10,120 --> 00:53:12,760
would on average infect
three others.

977
00:53:12,760 --> 00:53:16,840
They'd go on to infect three more,

978
00:53:16,840 --> 00:53:19,560
and so it spreads
through the population.

979
00:53:19,560 --> 00:53:23,160
But epidemiologist Mark Jit
has found

980
00:53:23,160 --> 00:53:26,600
that the increased transmissibility
of new variants

981
00:53:26,600 --> 00:53:28,960
could have changed this number.

982
00:53:28,960 --> 00:53:31,600
We knew that the proportion of cases

983
00:53:31,600 --> 00:53:35,640
with this variant was growing
in some parts of the UK.

984
00:53:35,640 --> 00:53:39,000
So what we did then was to take
this data and say,

985
00:53:39,000 --> 00:53:42,680
"Actually what set of parameters for
this virus is consistent

986
00:53:42,680 --> 00:53:44,480
"with what
we're seeing in the world?"

987
00:53:44,480 --> 00:53:49,360
And we found that the new variant
was about 50% more transmissible.

988
00:53:49,360 --> 00:53:51,960
We started off with a reproduction
number of three,

989
00:53:51,960 --> 00:53:55,800
so 50% more of that would be
around four, four and a half?

990
00:53:55,800 --> 00:53:57,680
It's difficult to say,

991
00:53:57,680 --> 00:54:01,120
because we haven't seen how fast
this variant spreads

992
00:54:01,120 --> 00:54:03,360
without any restrictions at all.

993
00:54:03,360 --> 00:54:05,000
But I think our best guess

994
00:54:05,000 --> 00:54:08,240
would be about four,
four and a half, yep.

995
00:54:09,360 --> 00:54:13,520
Let's be optimistic and use a
baseline reproduction number of four

996
00:54:13,520 --> 00:54:17,480
and let's keep our efficacy figure
at 77%.

997
00:54:17,480 --> 00:54:20,000
What you'll see happening then

998
00:54:20,000 --> 00:54:26,200
is that our herd immunity threshold
leaps up from 87%...

999
00:54:28,760 --> 00:54:30,440
..to 97%.

1000
00:54:33,560 --> 00:54:35,320
But will we ever be able

1001
00:54:35,320 --> 00:54:38,320
to vaccinate that many people
in reality?

1002
00:54:38,320 --> 00:54:41,560
So, Roy, herd immunity actually
works really well, doesn't it,

1003
00:54:41,560 --> 00:54:42,960
with some diseases?

1004
00:54:42,960 --> 00:54:44,400
It works very well.

1005
00:54:44,400 --> 00:54:46,840
I mean, the best example
in the United Kingdom

1006
00:54:46,840 --> 00:54:52,440
is the introduction of measles
vaccination roughly in 1967, '68,

1007
00:54:52,440 --> 00:54:54,760
and slowly over a period of
a few decades,

1008
00:54:54,760 --> 00:54:58,040
we built up sufficient immunity
in the population

1009
00:54:58,040 --> 00:55:00,960
that measles went from
800,000 cases a year

1010
00:55:00,960 --> 00:55:03,640
down to less than
1,000 cases a year.

1011
00:55:03,640 --> 00:55:07,760
We eradicated the transmission
of measles in the community.

1012
00:55:09,200 --> 00:55:13,800
In Britain, our success
against childhood measles

1013
00:55:13,800 --> 00:55:17,240
shows that achieving very high
vaccination levels against Covid-19

1014
00:55:17,240 --> 00:55:18,560
might be possible.

1015
00:55:19,960 --> 00:55:23,400
But there's one other
real-world thing to consider.

1016
00:55:23,400 --> 00:55:27,240
We've got new strains coming
into play, so it's important

1017
00:55:27,240 --> 00:55:29,920
to recognise that the duration
of immunity

1018
00:55:29,920 --> 00:55:33,320
for this coronavirus vaccine set is
unknown at present

1019
00:55:33,320 --> 00:55:36,360
and we will only find this out
in subsequent years.

1020
00:55:36,360 --> 00:55:41,480
What I do think is that we will
eradicate serious morbidity

1021
00:55:41,480 --> 00:55:46,200
and mortality, and hopefully
it will become one of these things

1022
00:55:46,200 --> 00:55:49,000
where every year, like influenza,

1023
00:55:49,000 --> 00:55:52,840
you have a vaccination against it.

1024
00:55:52,840 --> 00:55:55,120
Protecting those at risk with
vaccines may allow us

1025
00:55:55,120 --> 00:55:56,720
to live with the virus,

1026
00:55:56,720 --> 00:55:59,120
even without herd immunity.

1027
00:55:59,120 --> 00:56:00,760
And as we've heard this week,

1028
00:56:00,760 --> 00:56:03,440
this protection could help us
emerge from many of the current

1029
00:56:03,440 --> 00:56:06,560
restrictions as head
towards the summer.

1030
00:56:06,560 --> 00:56:08,800
What we all want is to be able

1031
00:56:08,800 --> 00:56:12,120
to see and be with each
other again safely.

1032
00:56:12,120 --> 00:56:14,480
The way to get there is to make sure

1033
00:56:14,480 --> 00:56:17,840
that population immunity is
as high as possible,

1034
00:56:17,840 --> 00:56:21,200
and vaccination means
that we can all play a part.

1035
00:56:23,960 --> 00:56:27,000
The pandemic continues to be
a human tragedy.

1036
00:56:27,000 --> 00:56:30,680
At the same time, our scientific
ingenuity has allowed us

1037
00:56:30,680 --> 00:56:32,880
to make great strides in
understanding

1038
00:56:32,880 --> 00:56:34,280
and fighting the virus.

1039
00:56:34,280 --> 00:56:36,560
Ever since the structure of
DNA was revealed,

1040
00:56:36,560 --> 00:56:39,960
the idea of genetic engineering
has been controversial.

1041
00:56:39,960 --> 00:56:42,000
But now our ability to understand

1042
00:56:42,000 --> 00:56:45,240
and manipulate life at its most
fundamental level

1043
00:56:45,240 --> 00:56:46,280
has paid dividends.

1044
00:56:46,280 --> 00:56:48,520
And it's because of this capability

1045
00:56:48,520 --> 00:56:51,040
that the innovative vaccines
have been delivered

1046
00:56:51,040 --> 00:56:53,680
and that globally, millions of
lives will be saved.

1047
00:56:53,680 --> 00:56:56,760
This knowledge is a cause
for some optimism,

1048
00:56:56,760 --> 00:56:59,120
not just about the end
of THIS pandemic,

1049
00:56:59,120 --> 00:57:02,000
but about those that we will
face in the future.