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Hello, I'm Chris Anderson.
Welcome to The TED Interview.
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We're gearing up for season four
with some extraordinary guests,
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but I don't want to wait for that
for today's episode,
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because we're in the middle of a pandemic,
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and there's a guest
I really wanted to talk to now.
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He is Adam Kucharski,
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an infectious diseases scientist
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who focuses on the mathematical
modeling of pandemics.
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He's an associate professor
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at the London School of Hygiene
and Tropical Medicine
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and a TED Fellow.
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(Music)
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(TED Talk) Adam Kucharski:
So what kind of behavior
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is actually important for epidemics?
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Conversations, close physical contacts?
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What sort of data should we be collecting
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before an outbreak
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if we want to predict
how infection might spread?
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To find out, our team
built a mathematical model ...
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Chris Anderson: When it comes
to figuring out what to make of
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this pandemic,
known technically as COVID-19,
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and informally as just the coronavirus,
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I find his thinking unbelievably helpful.
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And I'm excited to dive into it with you.
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A special callout to my friends on Twitter
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who offered up many
suggestions for questions.
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I know this topic
is on everyone's mind right now.
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And what I hope this episode does
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is give us all a more nuanced way
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of thinking about how this pandemic
has unfolded so far,
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what might be to come
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and what we all collectively
can do about it.
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Let's dive in.
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(Music)
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Adam, welcome to the TED Interview.
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Adam Kucharski: Thank you.
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CA: So let's just start
with a couple of basics.
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A lot of skeptical people's response --
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certainly over the last few weeks,
maybe less so now --
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has been, "Oh, come on,
this isn't such a big deal,
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there's a relatively tiny number of cases.
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Compare it to the flu,
compare it to anything else.
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There are much bigger
problems in the world.
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Why are we making such a fuss about this?"
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And I guess the answer to that fuss
is that it comes down to the mathematics.
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We're talking about the mathematics
of exponential growth,
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fundamentally, right?
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AK: Exactly.
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And there's a number that we use
to get a sense of how easy things spread
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and the level of transmission
we're dealing with.
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We call that the reproduction number,
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and conceptually, it's just,
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for each case you have, on average,
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how many others are they infecting?
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And that gives you a sense
of how much is this scaling,
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how much this growth
is going to look like.
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For coronavirus, we're now seeing,
across multiple countries,
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we're seeing each person on average
giving it to two or three more.
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CA: So that reproduction number,
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the first thing to understand
is that any number above one
-
means that this thing is going to grow.
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Any number below one
means it's going to diminish.
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AK: Exactly -- if you have it above one,
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then each group of people infected
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are going to be generating more infection
than there was before.
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And you will see the exponential effect,
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so if it's two, you will be doubling
every round of infection,
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and if it's below one,
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you're going to get something
that's going to decline, on average.
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CA: So that number two or higher,
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I think everyone here is maybe familiar
with the famous story
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of the chessboard and the grains of rice,
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and if you double the number of grains
for every square of the chessboard,
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for the first 10 or 15 squares
nothing much happens,
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but by the time you've got
to the 64th square,
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you suddenly have tons of rice
for every individual on the planet.
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(Laughs)
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Exponential growth is an incredible thing.
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And the small numbers now
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are really not what you
should be paying attention to --
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you should be paying attention
to the models of what could be to come.
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AK: Exactly.
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Obviously, if you continue
the exponential growth,
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you do sometimes get
these incredibly large,
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maybe implausibly large numbers.
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But even looking at a timescale
of say, a month,
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if the reproduction number is three,
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each person is infecting three on average.
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The gap between these rounds
of infection is about five days.
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So if you imagine
that you've got one case now,
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that's, kind of, six of these
five-day steps in a month.
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So by the end of that month,
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that one person could have generated,
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I think it works out at about 729 cases.
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So even in a month,
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just the scale of this thing
can really shoot up
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if it's not controlled.
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CA: And so certainly,
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that seems to be happening
on most numbers that you look at now,
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certainly where the virus
is in the early stages
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of entering a country.
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You've given a model
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whereby we can much more clearly
understand this reproduction number,
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because it seems to me this is almost
like the core to how we think of the virus
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and how we respond to it
and how much we should fear it, almost.
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And in your thinking,
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you sort of break it down
into four components,
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which you call DOTS:
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Duration, Opportunities,
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Transmission probability
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and Susceptibility.
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And I think it would be
really helpful, Adam,
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for you to just explain each of these,
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because it's quite a simple equation
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that links those four things
to the actual reproduction number.
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So talk about them in turn.
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Duration, what does that mean?
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AK: Duration measures
how long someone is infectious for.
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If, for example,
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intuitively, if someone is infectious
for a longer period of time,
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say, twice as long as someone else,
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then that's twice the length
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that they've got
to be spreading infection.
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CA: And what is the duration
number for this virus,
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compared with, say, flu
or with other pathogens?
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AK: It depends a little bit
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on what happens
when people are infectious,
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if they're being isolated very quickly,
that shortens that period of time,
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but potentially, we're looking
at around a week
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people are effectively infectious
before they might be isolated in hospital.
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CA: And during that week,
they may not even be showing symptoms
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for that full week either, right?
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So someone gets infected,
there's an incubation period.
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There's a period some way
into that incubation period
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where they start being infectious,
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and there may be a period after that,
where they start to show symptoms,
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and it's not clear, quite,
how those dates align.
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Is that right?
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AK: No, we're getting more information.
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One of the signals we see in data
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that suggest that you may have
that early transmission going on
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is when you have this delay
from one infection to the next.
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So that seems to be around five days.
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That incubation period,
the time for symptoms to appear,
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is also about five days.
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So if you imagine that most people
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are only infecting others
when they're symptomatic,
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you'd have that incubation period
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and then you'd have some more time
when they're infecting others.
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So the fact that those values
seem to be similar,
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suggesting that some people
are transmitting
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either very early on or potentially
before they're showing clear symptoms.
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CA: So almost implies that on average,
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people are infecting others
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as much before
they show symptoms as after.
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AK: Potentially.
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Obviously these are early data sets,
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but I think there's good evidence
that a fair number of people,
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either before they're
showing clear symptoms
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or maybe they're not showing the kind of
very distinctive fever and cough
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but they're feeling unwell
and they're shedding virus
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during that period.
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CA: And does that make it
quite different from the flu, for example?
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AK: It makes it actually
similar to flu in that regard.
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One of the reasons pandemic flu
is so hard to control
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and so feared as a threat
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is because so much transmission happens
before people are severely ill.
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And that means that by the time
you identify these cases,
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they've probably actually spread it
to a number of other people.
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CA: Yeah, so this is
the trickery of the thing,
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and why it's so hard
to do anything about it.
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It is ahead of us all the time,
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and you can't just pay attention
to how someone feels
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or what they're doing.
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I mean, how does that happen, by the way?
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How does someone infect someone else
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before they're even showing
symptoms themselves,
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because classically, we think of,
you know, the person sneezing
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and droplets go through the air
and someone else breathes them in
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and that's how infection happens.
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What is actually going on
for infection pre-symptoms?
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AK: So the level of transmission
we see with this virus
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isn't what we see,
for example, with measles,
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where someone sneezes
and a lot of virus gets out
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and potentially lots of susceptible
people can get exposed.
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So potentially, it could be quite early on
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that even if someone
has quite mild symptoms,
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maybe a bit of a cough,
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that's enough for some virus
to be getting out
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and particularly,
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some of the work that we've done
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trying to look at sort of
close gatherings,
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so very tight-knit meals,
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there was an example in a ski chalet --
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and even in those situations,
you might have someone mildly ill,
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but enough virus is getting out
and somehow exposing others,
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we're still trying
to work out exactly how,
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but there's enough there
to cause some infection.
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CA: But if someone's mildly ill,
don't they still have symptoms?
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Isn't there evidence that even before
they know that they're ill,
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something is going on?
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There was a German paper
published this week
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that seemed to suggest
that even really early on,
-
you take a swab from the back
of someone's throat
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and they have hundreds
of thousands of these viruses
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already reproducing there.
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Like, can someone just
literally just be breathing normally
-
and there is some transmission
of virus out into the air
-
that they don't even know about
-
and is either infecting people directly
-
or settling on surfaces, is that possible?
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AK: I think that's what
we're trying to pin down,
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how much that [unclear].
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As you said,
-
there's evidence that you can have
people without symptoms
-
and you can get virus out their throats.
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And so certainly there's potential
that it can be breathed out,
-
but is that a fairly rare event
for that actual transmission to happen,
-
or are we potentially seeing more
infections occur through that route?
-
So it's really early data,
-
and I think it's a piece of the puzzle,
-
but we're trying to work out
where that fits in
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with what we know about the kind of
other transmission events we've seen.
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CA: Alright, so, duration is the duration
of the period of infectiousness.
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We think is five to six days,
is that what I heard you say?
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AK: Potentially around a week,
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depending on exactly what happens
to people when they're infectious.
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CA: And there are cases
of people testing positive
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way, way later,
after they've got infected.
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That may be true, but they are probably
not as infectious then.
-
Is that basically right,
that's the way to think of this?
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AK: I think that's our working theory,
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that a lot of that infection
is happening early on.
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And we see that for a number
of respiratory infections,
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that when people obviously
become severely ill,
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their behavior is very different
-
to when they may be walking around
and going about their normal day.
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CA: And so again, comparing
that D number to other cases,
-
like the flu,
-
is flu similar?
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What's the D number for flu?
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AK: So for flu,
it's probably slightly shorter
-
in terms of the period
that people are actively infectious.
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I mean, for flu,
it's a very quick turnover
-
from one case to the next, actually.
-
Even a matter of
about three days, potentially,
-
from one infection
to the person that they infect.
-
And then at the other end of the scale,
you get things like STDs,
-
where that duration could be
several months, potentially.
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CA: Right.
-
OK, really nothing that unusual so far,
in terms of this particular virus.
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Let's look at the O, opportunity.
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What is that?
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AK: So opportunity is a measure
of how many chances
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the virus has to spread
through interactions
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while someone is infectious.
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So typically, it's a measure
of social behavior.
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On average, how many
social contacts do people make
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that create opportunities for transmission
while they're infectious.
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CA: So it's how many people
have you got close enough to
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during a day, during a given day,
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to have a chance of infecting them.
-
And that number could be,
-
if people aren't taking precautions
in a normal, sort of, urban setting,
-
I mean, that could run
into the hundreds, presumably?
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AK: Potentially, for some people.
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We've done a number of studies
looking at that in recent years,
-
and the average,
in terms of physical contacts,
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is about five people per day.
-
Most people will have
conversation or contacts
-
generally with about 10, 15,
-
but obviously,
-
between cultures,
we see quite a lot of variation
-
in the level of physical greetings
that might happen.
-
CA: And presumably, that number
again is no different for this virus
-
than for any other.
-
I mean, that's just a feature
of the lives that we live.
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AK: I think for this one,
-
if it's driven through
these kind of interactions,
-
and we've seen for flu,
for other respiratory infections,
-
those kinds of fairly close contacts
and everyday physical interactions
-
seem to be the ones
that are important for transmission.
-
CA: Perhaps there is one difference.
-
The fact that if you're
infectious pre-symptoms,
-
perhaps that means that actually,
there are more opportunities here.
-
This is part of the virus's
genius, as it were,
-
that by not letting on
that it's inside someone,
-
people continue to interact and go to work
-
and take the subway and so forth,
-
not even knowing that they're sick.
-
AK: Exactly.
-
And for something like flu,
-
you see when people get ill, clearly,
their social contacts drop off.
-
So to have a virus that can be infectious
-
while people are going around
their everyday lives,
-
really gives it an advantage
in terms of transmission.
-
CA: In your modeling,
-
do you actually have this
opportunities number higher than for flu?
-
AK: So for the moment,
we're kind of using similar values,
-
so we're trying to look at, for example,
-
physical contacts
within different populations.
-
But what we are doing is scaling the risk.
-
So that's coming on to the T term.
-
So that between each contact,
-
what's the risk that a transmission
event will occur.
-
CA: Alright, so let's go on
to this next number,
-
the T, transmission probability.
-
How do you define that?
-
AK: So this measures the chance
-
that, essentially,
the virus will get across
-
during a particular opportunity
or a particular interaction.
-
So you may well have
a conversation with somebody,
-
but actually, you don't cough
or you don't sneeze
-
or for some reason,
the virus doesn't actually get across
-
and expose the other person.
-
And so, for this virus, as I mentioned,
-
say people are having
10 conversations a day,
-
but we're not seeing infected people
infect 10 others a day.
-
So it suggests that not all
of those opportunities
-
are actually resulting
in the virus getting across.
-
CA: But people say
that this is an infectious virus.
-
Like, what is that transmission
probability number,
-
again, compared with, say, the flu?
-
AK: So, we did some analysis
looking at these very close gatherings.
-
We looked at about 10
different case studies,
-
and we found that about a third
of the contacts in those settings
-
subsequently got infected
-
in these early stages,
when people weren't aware.
-
So if you had these, kind of,
big group meals,
-
potentially, each contact
had about, a kind of, one in three chance
-
of getting exposed.
-
For seasonal flu,
that tends to be slightly lower,
-
even within households
and close settings,
-
you don't necessarily
get values that high.
-
And even for something like SARS,
those values have, kind of --
-
the risk per interaction you had
-
was lower than what we seem
to be getting for coronavirus.
-
Which intuitively makes sense,
-
there must be a higher risk
per interaction
-
if this thing is spreading so easily.
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CA: Hm.
-
OK, and then the fourth letter of DOTS
-
is S for susceptibility.
-
What's that?
-
AK: So that is a measure of the proportion
of the population who are susceptible.
-
If you imagine you have
this interaction with someone,
-
the virus gets across, it exposes them,
-
but some people may have been vaccinated
-
or otherwise have some immunity
-
and not develop infection themselves
-
and not be infectious to others.
-
So we've got to account for this
potential proportion of people
-
who are not actually
going to turn into cases themselves.
-
CA: And obviously, there's no vaccine yet
for this coronavirus,
-
nor is anyone, at least initially,
immune, as far as we know.
-
So are you modeling that
susceptibility number pretty high,
-
is that part of the issue here?
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AK: Yeah, I think the evidence
-
is that this is going to fully
susceptible populations,
-
and even in areas,
for example, like China,
-
where there's been a lot of transmission
-
but there's been very strong
control measures,
-
we estimated that up to
the end of January,
-
probably about 95 percent of Wuhan
are still susceptible.
-
So there's been a lot of infection,
-
but it hasn't really taken much
of that component,
-
of the DOTS, of those four things
that drive transmission.
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CA: And so the way the mathematics works,
-
I have to confess, amidst the stress
of this whole situation,
-
the nerd in me kind of loves
the elegance of the mathematics here,
-
because I'd never really
thought about it this way,
-
but you basically just multiply
those numbers together
-
to get the reproduction number.
-
Is that right?
-
AK: Exactly, yeah,
-
you almost take the path
of the infection during transmission
-
as you multiply those together,
-
and that gives you
the number for that virus.
-
CA: And so there's just
a total logic to that.
-
It's the number of days,
duration that you're infectious,
-
it's the number of people
you're seeing on average
-
during those days
that you have a chance to infect.
-
Then you multiply that
by the transmission probability,
-
is virus getting into them, essentially,
-
that's what you mean by crossing over.
-
And then by the susceptibility number.
-
By the way, what do you think
the susceptibility probability is
-
for this case?
-
AK: I think we have to assume
that it's near 100 percent
-
in terms of spread, yeah.
-
CA: Alright, you multiply
those numbers together,
-
and right now, it looks like,
for this coronavirus,
-
that you say two to three
is the most plausible current number,
-
which implies very rapid growth.
-
AK: Exactly.
-
In these uncontrolled outbreaks,
-
we're seeing now a number
of countries in this stage --
-
you are going to get
this really rapid growth occurring.
-
CA: And so how does
that two to three compare with flu?
-
And I guess, there's seasonal flu,
-
in the winter, when it's spreading,
-
and at other times during the year
drops well below one
-
as a reproduction number, right?
-
But what is it during seasonal flu time?
-
AK: During the early stage
when it's taking off
-
at the start of the flu season,
-
it's probably, we reckon,
somewhere between about maybe 1.2, 1.4.
-
So it's not incredibly transmissible,
-
if you imagine you do have some immunity
in your population from vaccination
-
and from other things.
-
So it can spread, it's above one,
-
but it's not taking off, necessarily,
as quickly as the coronavirus is.
-
CA: So I want to come back
to two of those elements,
-
specifically opportunity
and transmission probability,
-
because those seem to have the most
chance to actually do something
-
about this infection rate.
-
Before we go there,
-
let's talk about another
key number on this,
-
which is the fatality rate.
-
First of all, could you define --
-
I think there's two different versions
of the fatality rate
-
that maybe confuse people.
-
Could you define them?
-
AK: So the one that we often talk about
is what's known as the case fatality rate,
-
and that's of the proportion who show up
with symptoms as cases,
-
what proportion of those
will subsequently be fatal.
-
And we also sometimes talk
about what's known
-
as the infection fatality rate,
-
which is, of everyone who gets infected,
-
regardless of symptoms,
-
how many of those infections
will subsequently be fatal.
-
But most of the values
we see kicking around
-
are the case fatality rate, or the CFR,
as it's sometimes known.
-
CA: And so what is
that fatality rate for this virus,
-
and again, how does that compare
with other pathogens?
-
AK: So there's a few numbers
that have been bouncing around.
-
One of the challenges in real time
is you often don't see all of your cases,
-
you have people symptomatic
not being reported.
-
You also have a delay.
-
If you imagine, for example,
-
100 people turn up to a hospital
with coronavirus
-
and none have died yet,
-
that doesn't imply
that the fatality rate is zero,
-
because you've got to wait to see
what might happen to them.
-
So when you adjust for that
underreporting and delays,
-
best estimate for the case fatality
is about one percent.
-
So about one percent
of people with symptoms,
-
on average,
-
those outcomes are fatal.
-
And that's probably about 10 times
worse than seasonal flu.
-
CA: Yeah, so that's a scary
comparison right there,
-
given how many people die of flu.
-
So when the World Health Organization
mentioned a higher number,
-
a little while back, of 3.4 percent,
-
they were criticized a bit for that.
-
Explain why that
might have been misleading
-
and how to think about it
and adjust for that.
-
AK: It's incredibly common that people
look at these raw numbers,
-
they say, "How many deaths
are there so far, how many cases,"
-
and they look at that ratio,
-
and even a couple of weeks ago,
that number produced a two percent value.
-
But if you imagine
you have this delay effect,
-
then even if you stop all your cases,
-
you will still have these kind of
fatal outcomes over time,
-
so that number will creep up.
-
This has occurred in every epidemic
from pandemic flu to Ebola,
-
we see this again and again.
-
And I made the point to a number of people
that this number is going to go up,
-
because as China's cases slow,
-
it will look like it's increasing,
-
and that's just kind of
a statistical quirk.
-
There's nothing really
kind of, behind the change,
-
there's no mutations or anything going on.
-
CA: If I have this right,
there are two effects going on.
-
One is that the number of fatalities
-
from the existing caseload will rise,
-
which actually would boost
that 3.4 even higher.
-
But then you have to offset that
against the fact that apparently,
-
huge numbers of cases
have just gone undetected
-
and that we haven't,
-
due to bad testing,
-
that the number of fatalities don't --
-
They probably reflect
a much larger number of early cases.
-
Is that it?
-
AK: Exactly.
-
So you have one thing
pulling the number up,
-
and one thing pulling it down.
-
And it means that on these
kind of early values,
-
if you actually just adjust for the delay,
-
and don't think
about these unreported cases,
-
you start getting really
very scary numbers indeed.
-
You get up to 20, 30 percent potentially,
-
which really doesn't align
-
with what we know
about this virus in general.
-
CA: Alright.
-
There's a lot more data in now.
-
From your point of view,
you think the likely fatality rate,
-
at least in the earlier stage
of an infection,
-
is about two percent?
-
AK: I think overall,
-
I think we can put something probably
in the 0.5 to two percent range,
-
and that's on a number
of different data sets.
-
And that's for people who are symptomatic.
-
I think on average, one percent
is a good number to work with.
-
CA: OK, one percent,
-
So flu is often quoted
as a tenth of a percent,
-
so it's five to ten times or more
more dangerous than flu.
-
And that danger is not symmetric
across age groups,
-
as is well known.
-
It primarily affects the elderly.
-
AK: Yeah, we've seen
that one percent on average,
-
but once you start getting
into the over 60s, over 70s,
-
that number really starts to shoot up.
-
I mean, we're estimating
potentially in these older groups,
-
you're looking at maybe five,
ten percent fatality.
-
And then of course, on top of that,
-
you've got to add what
are going to be the severe cases
-
and people are going to require
hospitalization.
-
And those risks get very large
in the older groups indeed.
-
CA: Adam, put these numbers
together for us.
-
In your models,
-
if you put together
a reproduction rate of two to three
-
and a fatality rate
of 0.5 percent to one percent,
-
and you run the simulation,
-
what does it look like?
-
AK: So if you have
this uncontrolled transmission,
-
and you have this reproduction
number of two or three
-
and you don't do anything about it,
-
the only way the outbreak ends
-
is enough people get it
and immunity builds up
-
and the outbreak kind of ends on its own.
-
And in that case,
-
you would expect very large numbers
of the population to be infected.
-
It's what we see, for example,
-
with many other uncontained outbreaks,
-
that it essentially burns
through the population,
-
you get large numbers infected
-
and with this kind of fatality rate
and hospitalization rate,
-
that would really be hugely damaging
if that were to occur.
-
Certainly at the country level,
we're seeing --
-
Italy is a good example at the moment,
-
that if you have that early
transmission is undetected,
-
that rapid growth,
-
you very quickly get to a situation
where your health systems are overwhelmed.
-
I think one of the nastiest
aspects of this virus
-
is that because you have the delay
between infection and symptoms
-
and people showing up in health care,
-
if your health system is overwhelmed,
-
even on that day,
-
if you completely stop transmission,
-
you've got all of these people
who have already been exposed,
-
so you're still going to have cases
and severe cases appearing
-
for maybe another couple of weeks.
-
So it's really this huge
accumulation of infection and burden
-
that's coming through the system
on your population.
-
CA: So there's another
key number, actually,
-
is how does the total case number
-
compare to the capacity
of a country's health system
-
to process that number of cases.
-
Presumably that issue
makes a huge difference
-
to the fatality rate,
-
the difference between people
coming in with severe illness
-
and a health system that's able
to respond and one that's overwhelmed.
-
The fatality rate is going to be
very different at that point.
-
AK: If someone requires an ICU bed,
-
that's a couple of weeks
they're going to require it for
-
and you've got more cases
coming through the system,
-
so it very quickly gets very tough.
-
CA: So talk about the difference
between containment
-
and mitigation.
-
These are different terms
that we're hearing a lot about.
-
In the early stages of the virus,
governments are focused on containment.
-
What does that mean?
-
AK: Containment is this idea
that you can focus your effort on control
-
very much on the cases and their contacts.
-
So you're not causing disruption
to the wider population,
-
you have a case that comes in,
you isolate them,
-
you work out who they've come
into contact with,
-
who's potentially these
opportunities for exposure,
-
and then you can follow up those people,
-
maybe quarantine them to make sure
that no further transmission happens.
-
So it's a very focused, targeted method,
-
and for SARS, it worked remarkably well.
-
But I think for this infection,
-
because some cases are going to be missed,
they're going to be undetected,
-
you've really got to be capturing
a large chunk of people at risk.
-
If a few slip through the net,
-
potentially, you're going
to get an outbreak.
-
CA: Are there any countries
-
that have been able
to employ this strategy
-
and effectively contain the virus?
-
AK: So Singapore have been doing
a really remarkable job of this
-
for the last six weeks or so.
-
So as well as some wider measures,
-
they've been working incredibly hard
-
to trace people
who have come into contact.
-
Looking at CCTV,
-
going through to find out
which taxi someone might have gotten,
-
who might be at risk --
-
really, really thorough follow up.
-
And for about six weeks,
that has kept a lid on transmission.
-
CA: So that's amazing.
-
So someone comes into the country,
-
they test positive --
-
they go to work, and with a massive team,
-
and trace everything,
-
to the level of actually saying,
-
"Oh, you don't know what taxi you went in?
-
Let us find that out for you."
-
And presumably,
when they find the taxi driver,
-
they then have to try and figure out
everyone else who was in that taxi?
-
AK: So they will focus on
close contacts of people most at risk,
-
but they're really minimizing the chance
that anyone slips through the net.
-
CA: But even in Singapore,
if I'm not mistaken,
-
numbers started to trend
back down to zero,
-
but I think recently,
they've picked up again a bit.
-
It's still unclear
-
whether they will actually
be able to sustain containment.
-
AK: Exactly.
-
If we talk in terms
of the reproduction number,
-
we saw it dipped to maybe 0.8, 0.9,
-
so under that crucial value of one.
-
But in the last week or two,
-
it does seem to be taking up
and they're getting more cases appearing.
-
I think a lot of it is,
-
even if they are containing it,
-
the world is experiencing outbreaks
-
and just keeps throwing
sparks of infection,
-
and it becomes harder and harder
-
with that level of intensive effort
to stamp them all out.
-
(Music)
-
CA: In the case of this virus,
-
you know, there was warning
to most countries in the world
-
that this thing was happening.
-
The news out of China
very quickly became very bleak
-
and people had time to prepare.
-
I mean, what would an ideal
preparation look like
-
if you know that something
like this is coming
-
and you know that there's
a lot on the line
-
if you can successfully contain it
before it really escapes?
-
AK: I think two things
would make a really big difference.
-
One is having as thorough follow up
and detection as possible.
-
We've done some modeling analyses,
-
looking at how effective
that kind of early containment is.
-
And it can be, if you're identifying
maybe 70 or 80 percent
-
of the people who might have
come into contact.
-
But if you're not detecting
those cases coming in,
-
if you're not detecting their contacts --
-
and a lot of the early focus, for example,
was on travel history to China,
-
and then it became clear
that the situation was changing,
-
but because you were relying on that
as your definition of a case,
-
it meant a lot of maybe other cases
that matched the definition
-
weren't being tested
-
because they didn't seem
to be potentially at risk.
-
CA: So I mean, if you know
that early detection is key to this,
-
an essential early measure, I guess,
-
would be to rapidly ensure
that you had enough tests available,
-
and where needed,
-
so that you could respond,
-
be ready to swing into action
as soon as someone was detected,
-
you then have to very quickly,
I guess, test their contacts and so forth,
-
to have a chance
of keeping this under control.
-
AK: Exactly.
-
In my line of work, we say
there's value in a negative test,
-
because it shows that you're looking
for something and it's not there.
-
And so I think having
small numbers of people tested
-
doesn't give you confidence
that you're not missing infections,
-
whereas if you are doing
really thorough follow up on contacts,
-
we've seen countries even like Korea now,
-
huge numbers of people tested.
-
So although there are still
cases appearing,
-
it gives them more confidence
-
that they have some sense
of where those infections are.
-
CA: I mean, you're in the UK right now,
-
I'm in the US.
-
How likely is it that the UK
is going to be able to contain,
-
how likely is it that the US
is going to be able to contain this?
-
AK: I think it's pretty
unlikely in both cases.
-
I think the UK is going to have
to introduce some additional measures.
-
I think when that happens
obviously depends a bit
-
on the current situation,
-
but we've tested almost 30,000 people now.
-
Frankly, I think the US
may well be moving beyond that point,
-
given how much evidence
of extensive transmission that has,
-
and I think without clear ideas
of how much infection there is
-
and that level of testing,
-
it's quite hard to actually see
what the picture currently is in the US.
-
CA: I mean, I definitely don't want to get
too political about this,
-
but I mean, does this strike you as --
-
you just said that the UK
has tested 30,000 people --
-
the US is five or six times bigger
-
and I think the total number
of tests here is five or six thousand,
-
or it was a few days ago.
-
Does that strike you as bizarre?
-
I don't understand, honestly,
how that happened in an educated country
-
that has so much knowledge
about infectious diseases.
-
AK: It does,
-
and I think there's obviously
a number of factors playing in there,
-
logistics and so on,
-
but there has been that period of warning
-
that this is a threat
and this is coming in.
-
And I think countries need to make sure
that they've got the capacity
-
to really do as much detection as they can
in those early stages,
-
because that's where
you're going to catch it
-
and that's where you're going to have
a better chance of containing it.
-
CA: OK, so if you fail to contain,
-
then you have to move
to some kind of mitigation strategy.
-
So what comes into play there?
-
And I think I almost want
to bring that back
-
to two of your DOTS factors,
-
opportunity and transmission probability,
-
because it seems like
the virus is what it is,
-
the actual duration when someone
is potentially infectious,
-
we can't do much about.
-
The susceptibility side,
-
we can't do much about
until there's a vaccine.
-
We could maybe talk about that in a bit.
-
But the middle two of opportunity
and transmission probability,
-
we can do something about.
-
Do you want to maybe talk
about those in turn,
-
of what that looks like,
-
how would you build a mitigation strategy?
-
I mean, first of all,
thinking about opportunity,
-
how do you reduce
the number of opportunities
-
to pass on the bug?
-
AK: And so I think in that respect,
-
it would be about massive changes
in our social interactions.
-
And if you think in terms
of the reproduction number
-
of being about two or three,
-
to get that number below one,
-
you've really got to cut
some aspect of that transmission
-
in half or in two thirds,
-
to get that below one.
-
And so that would require,
-
of the opportunities
that could spread the virus
-
are these kind of close contacts.
-
Everybody in the population, on average,
-
will be needing to reduce
those interactions
-
potentially by two thirds
to bring it under control.
-
That might be through working from home,
-
from changing lifestyle
-
and kind of where you go
in crowded places and dinners.
-
And of course, these measures,
things like school closures,
-
and other things
that just attempt to reduce
-
the social mixing of a population.
-
CA: Well, actually, talk to me more
about school closures,
-
because that, if I remember,
-
often in past pandemics has been cited
as an absolutely key measure,
-
that schools represent this sort of
coming together of people,
-
children are often --
-
certainly when it comes to flu and colds,
-
they're carriers.
-
But on this case,
-
children don't seem to be getting sick
from this particular virus,
-
or at least very few of them are.
-
Do we know whether they
can still be infectious?
-
They can be the unintended carriers of it.
-
Or actually, is there evidence
that school closures
-
may not be as important
in this instance as it is in others?
-
AK: So that point
on what role children play
-
is a crucial one,
-
and there's still not
a good evidence base there.
-
From following up of contacts of cases,
-
there's now evidence
that children are getting infected,
-
so when you're testing,
they are getting exposed,
-
it's not that somehow they're just
not getting the infection at all,
-
but as you said, they're not showing
symptoms in the same way,
-
and particularly for flu,
-
when we see the implications
of school closures,
-
even in the UK in 2009 during swine flu,
-
there was a dip in the outbreak
during the school holidays,
-
you could see it on the epidemic curve,
-
it kind of comes back down in the summer
and goes back up in the autumn.
-
But of course, in 2009,
there was some immunity in older groups.
-
That kind of shifted more the transmission
onto the younger ones.
-
So I think it's really something
we're trying to work to understand.
-
Obviously, it will reduce interactions,
with school closures,
-
but then there's knock-on social effects,
-
there's potential
knock-on changes in mixing,
-
maybe grandparents and their role
in terms of alternative carers
-
if parents have to work.
-
So I think there's a lot of pieces
that need to be considered.
-
CA: I mean, based on all of the different
pieces of evidence you've seen,
-
if it were down to you,
-
would you be recommending
that most countries at this point
-
do look hard at extensive school closures
as a precautionary measure,
-
that it's just worth it to do that
-
as a sort of painful two,
three, four, five-month strategy?
-
What would you recommend?
-
AK: I think the key thing,
-
given the age distribution of risk
and the severity in older groups
-
is reduce interactions that bring
the infection into those groups.
-
And then amongst everyone else,
reduce interactions as much as possible.
-
I think the key thing is
-
we've got so much of the disease burden
in the kind of 60-plus group
-
that it's not just about
everyone trying to avoid
-
everyone's interactions,
-
but it's the kind of behaviors
-
that would drive infections
into those groups.
-
CA: Does that mean
that people should think twice
-
before, I don't know, visiting a loved one
-
in an old people's home
or in a residential facility?
-
Like that, we should just pay
super special attention to that,
-
should all these facilities
be taking great care
-
about who they admit,
-
taking temperature and checking
for symptoms or something like that?
-
AK: I think those measures
definitely need to be considered.
-
In the UK, we're getting plans
-
for potentially what's known
as a cocooning strategy
-
for these older groups
-
that we can really try
and seal off interactions
-
as much as possible
-
from people who might
be bringing infection in.
-
And ultimately, because as you said,
-
we can't target these other
aspects of transmission,
-
it is just reducing the risk
of exposure in these groups,
-
and so I think anything
at the individual level you can do
-
to get people reducing their risk,
-
if either they're elderly
or in other risk groups,
-
I think is crucial.
-
And I think more at the general level
-
those kind of more large-scale measures
can help reduce interactions overall,
-
but I think if those
reductions are happening,
-
and not reducing the risk
-
for people who are going
to get severe disease,
-
then you're still going to get
this really remarkably severe burden.
-
CA: I mean, do people have to almost
apply this double lens
-
as they think about this stuff?
-
There's the risk to you
as you go about your life,
-
of you catching this bug.
-
But there's also the risk
of you being, unintentionally, a carrier
-
to someone who would suffer
much more than you might.
-
And that both those things
have to be top of mind right now.
-
AK: Yeah, and it's not just
whose hand you shake,
-
it's whose hand that person
goes on to shake.
-
And I think we need to think
about these second-degree steps,
-
that you might think you have low risk,
-
and you're in a younger group,
-
but you're often going to be
a very short step away
-
from someone who is going to get hit
very hard by this.
-
And I think we really need
to be socially minded
-
and think this could be quite dramatic
in terms of change of behavior,
-
but it needs to be
-
to reduce the impact
that we're potentially facing.
-
CA: So the opportunity
number, we bring down
-
by just reducing the number
of physical contacts we have
-
with other people.
-
And I guess the transmission
probability number,
-
how do we bring that down?
-
That impacts how we interact.
-
You mentioned hand-shaking,
-
I'm guessing you're going to say
no handshaking.
-
AK: Yeah, so changes like that.
-
I mean, another one, I think,
-
handwashing operates in a way
-
that we might be still be doing
activities that we've previously done,
-
but handwashing reduces the chance
that from one interaction to another,
-
we might be spreading infection,
-
so it's all of these measures
-
that mean that even
if we're having these exposures,
-
we're taking additional steps
to avoid any transmission happening.
-
CA: I still think most people
don't fully understand
-
or don't have a clear model of the pathway
-
by which thins thing spreads.
-
So you think definitely people understand
-
that you don't breathe in
-
the water droplets of someone
who has just coughed or sneezed.
-
So how does it spread?
-
It gets onto surfaces. How?
-
Do people just breathe out
and it goes on from people who are sick,
-
they touch their mouth
or something like that,
-
and then touch a surface
and it gets on that way?
-
How does it actually get onto surfaces?
-
AK: I think a lot of it would be
that you cough in your hand
-
and it ends up on a surface.
-
But I think the challenge, obviously,
is untangling these questions
-
of how transmission happens.
-
You have transmission in a household,
-
and is it that someone coughed
and it got on a surface,
-
is it direct contact, is it a handshake,
-
and even for things like flu,
-
that's something that we work
quite hard to try and unpick,
-
how does social behavior correspond
to infection risk.
-
Because it's clearly important,
but pinning it down is really tough.
-
CA: It's almost like embracing the fact
-
that for a lot of these things,
we actually don't know
-
and that we're all
in this game of probabilities.
-
Which, in a way, is why I think
the math is so important here.
-
That you have to think of this
as these multiple numbers
-
working together on each other,
-
they all have their part to play.
-
And any of them that you can
take down by a percentage
-
is likely contributing,
-
not just to you, but to everyone.
-
And people don't actually know
in detail how the numbers go together,
-
but they know that they
probably all matter.
-
We almost need people to, somehow,
you know, embrace that uncertainty
-
and then try to get some satisfaction
by acting on every single part of it.
-
AK: I think it's this idea
-
that if on average,
you're infecting, say, three people,
-
what's driving that and how can you
chip away at that value?
-
If you're washing your hands,
-
how much might that chip away
in terms of the handshakes,
-
you know, you may have had virus
and you no longer do,
-
or if you are changing
your social behavior in a certain way,
-
is that taking away
a couple of interactions,
-
is that taking away half,
-
how can you really chip into that number
as much as you possibly can?
-
CA: Is there anything else to say
about how we could reduce
-
that transmission probability
in our interactions?
-
Like, what is the physical distance
-
that it's wise to stay away
from other people if we can?
-
AK: I think it's hard to pin down exactly,
-
but I think one thing to bear in mind
is that there's not so much evidence
-
that this is a kind of aerosol
and it goes really far --
-
it's reasonably short distances.
-
I don't think it's the case
-
that you're sitting a few meters
away from someone
-
and the virus is somehow
going to get across.
-
It's in closer interactions,
-
and it's why we're seeing
so many transmission events
-
occur in things like meals
and really tight-knit groups.
-
Because if you imagine
-
that's where you can get
a virus out and onto surfaces
-
and onto hands and onto faces,
-
and it's really situations like that
we've got to think more about.
-
CA: So in a way,
-
some of the fears that people have
may actually be overstated,
-
like, if you're in the middle
of an airplane
-
and someone at the front sneezes,
-
I mean, that's annoying,
-
but it's actually not the thing
you should be most freaked out about.
-
There are much smarter ways
to pay attention to your well-being.
-
AK: Yeah, if it was measles
and the plane is susceptible people,
-
you would see a lot
of infections after that.
-
I think it is, bear in mind,
that this is, on average,
-
people infecting two or three others,
-
so it's not the case of your
maybe 50 interactions over a week,
-
all of those people are at risk.
-
But it's going to be some of them,
-
particularly those close contacts,
-
that are going to be
where transmission's occurring.
-
CA: So talk about,
-
from a sort of national
strategy point of view.
-
There's a lot of talk about the need
to "flatten the curve."
-
What does that mean?
-
AK: I think it refers to this idea
that for your health systems,
-
you don't want all your cases
to appear at the same time.
-
So if we sat back and did nothing,
-
and just let the epidemic grow,
-
and you had this growth rate
that, at the moment,
-
in some places is looking like maybe
-
three to four days,
you're getting doubling.
-
So every three or four days,
the epidemic is doubling.
-
It will skyrocket and you'll end up
-
with a whole bunch
of really severely ill people
-
needing hospital care
all at the same time,
-
and you just won't have capacity for it.
-
So the idea of flattening the curve
is if we can slow transmission,
-
if we can get that
reproduction number down,
-
then there may still be an outbreak,
-
but it will be much flatter,
-
it will be longer,
-
and there will be fewer
severe cases showing up,
-
which means that they can get
the health care they need.
-
CA: Does it imply that there will be
fewer cases overall, or ---
-
When you look at the actual images
of people showing
-
what flattening the curve looks like,
-
it almost looks as if you've got
the same area still under the graph,
-
i.e. that the same number of people,
ultimately, are infected,
-
but over a longer period.
-
Is that typically what happens,
-
and even if you adopt
all these strategies of social distancing
-
and washing hands and etc.
-
that the best you can hope for
is that you slow the thing down,
-
you actually will get
as many people infected in the end?
-
AK: Not necessarily --
it depends on the measures that go in.
-
There are some measures like,
shutting down travel,
-
which typically delay the spread
rather than reduce it.
-
So you're still going to get
the same outbreaks,
-
but you're stretching out the outbreaks.
-
But there are other measures.
-
If we talk about reducing interactions,
-
if your reproduction number's lower,
-
you would expect fewer cases overall.
-
And eventually, in your population,
-
you will get some buildup of immunity,
-
which would help you out
if you think about the components,
-
reducing susceptibility,
-
alongside what's going on elsewhere.
-
So the hope is that the two things
will work together.
-
CA: So help me understand
what the endgame is here.
-
So, take China, for example.
-
Whatever you make
of the early suppression of data
-
and so forth,
-
that seems pretty troubling there.
-
The intensity of the response
come January time or whatever,
-
with the shutdown
of this huge area of the country,
-
seems to have actually been effective.
-
The number of cases there are falling
at a shockingly high rate in some ways.
-
Falling to almost nothing.
-
And I can't understand that.
-
You are talking about a country
of, whatever, 1.4 billion people.
-
There have been a huge
number of cases there,
-
but it was a tiny fraction
of the population have actually got sick.
-
And yet, they've got the number way down.
-
It's not like every other person in China
has somehow developed immunity.
-
Is it that they have been
absolutely disciplined
-
about shutting down travel
from the infected regions
-
and somehow really dialed up,
massively dialed up
-
testing at any sign of any problem,
-
so that literally, they are back
in containment mode
-
in most parts of China?
-
I can't get my head around it,
help me understand it.
-
AK: So we estimated,
in the last two weeks of January,
-
when these measures went in,
-
the reproduction number
went from about 2.4 to 1.1.
-
So about 60 percent decline
in transmission
-
in the space of a week or two.
-
Which is remarkable and really,
-
a lot of it is likely to be driven
by just fundamental change
-
in social behavior,
-
huge social distancing,
-
really intensive follow up,
intensive testing.
-
And it got to the point
-
where it took enough
off the reproduction number
-
to cause the decline,
-
and of course,
we're seeing, in many areas,
-
a transition back to more
of this kind of containment,
-
because there's few cases,
it's more manageable.
-
But we're also seeing them
face a challenge,
-
because a lot of these cities
have basically been locked down
-
for six weeks
-
and there's a limit to how long
you can do that for.
-
And so some of these measures
are gradually starting to be lifted,
-
which of course creates the risk
-
that cases that are appearing
from other countries
-
may subsequently go in
and reintroduce transmission.
-
CA: But given how infectious the bug is,
-
and how many theoretical pathways
and connection points there are
-
between people in Wuhan, even in shutdown,
-
or relatively shut down,
-
or the other places
where there's been some infection
-
and the rest of the country,
-
does it surprise you how quickly
that curve has gone down to nearly zero?
-
AK: Yes.
-
Early on when we saw
that flattening off in cases
-
in those first few days,
-
we did wonder whether it was just
they hit a limit in testing capacity
-
and they were reporting 1,000 a day,
-
because that's all the kits they had.
-
But it continued, thankfully,
-
and it shows that it is possible
to turn this over
-
with that level of intervention.
-
I think the key thing now
is seeing how it works in other settings.
-
Italy now are putting in
really dramatic interventions.
-
But of course,
because of this delay effect,
-
if you put them in today,
-
you won't necessarily see
the effects on cases
-
for another week or two.
-
So I think working out
what impact that's had
-
is going to be key for helping
other countries
-
work on how to contain this.
-
CA: To have a picture, Adam,
-
of how this is likely to play out
over the next month or two,
-
give us a couple of scenarios
that are in your head.
-
AK: I think the optimistic scenario
-
is that we're going to learn a lot
from places like Italy
-
that have unfortunately
been hit very hard,
-
and that countries are going to take
this very seriously
-
and that we're not going to get
this continued growth
-
that's going to overwhelm totally,
-
that we're going to be able
to sufficiently slow it down,
-
that we are going to get
large numbers of cases,
-
we're probably going to get
a lot of severe cases,
-
but that will be more manageable,
-
that's the kind of optimistic scenario.
-
I think if we have a point
-
where countries either
don't take this seriously
-
or populations don't respond well
to control measures
-
or it's not detected,
-
we could get situations --
-
I think Iran is probably
the closest one at the moment --
-
where there's been extensive
widespread transmission,
-
and by the time it's being responded to,
-
those infections are already in the system
-
and they are going to turn up
as cases and severe illness.
-
So I'm hoping we're not at that point,
-
but we've certainly got, at the moment,
-
potentially about 10 countries
on that trajectory
-
to have the same outlook as Italy.
-
So it's really crucial what happens
in the next couple of weeks.
-
CA: Is there a real chance
that quite a few countries
-
end up having, this year,
-
substantially more deaths from this virus
than from seasonal flu?
-
AK: I think for some countries
that is likely, yeah.
-
I think if control is not possible,
-
and we've seen it happen in China,
-
but that was really just an unprecedented
level of intervention.
-
It was really just changing
the social fabric.
-
I think people, many of us,
don't really appreciate, at a glance,
-
just what that means,
-
to reduce your interactions
to that extent.
-
I think many countries just simply
won't be able to manage that.
-
CA: It's almost a challenge
to democracies, isn't it --
-
"OK, show us what you can do
without that kind of draconian control."
-
If you don't like the thought of that,
-
come on, citizens, step up,
show us what you're capable of,
-
show that you can be wise about this
-
and smart and self-disciplined,
-
and get ahead of the damn bug.
-
AK: Yeah.
-
CA: I mean, I'm not personally
superoptimistic about that,
-
because there's such conflicting messaging
coming out in so many different places,
-
and people don't like
to short-term sacrifice.
-
I mean, is there almost a case that --
-
I mean, what's your view
-
on whether the media has played
a helpful role here
-
or an unhelpful role?
-
Is it actually, in some ways, helpful
-
to, if anything, overstate
the concern, the fear,
-
and actually make people
panic a little bit?
-
AK: I think it's a really
tough balance to strike,
-
because of course, early on,
if you don't have cases,
-
if you don't have any evidence
of potential pressure,
-
it's very hard to get that message
and convince people to take it seriously
-
if you're over hyping it.
-
But equally, if you're waiting too long,
-
and saying it's not a concern yet,
we're OK for the moment,
-
a lot of people think it's just flu.
-
By the time it hits hard, as I've said,
-
you're going to have weeks
of an overburdened health system,
-
because even if you take interventions,
-
it's too late to control the infections
that have happened.
-
So I think it's a fine line
-
and my hope is there is
this ramp-up in messaging,
-
now people have these
tangible examples like Italy,
-
where they can see what's going to happen
if they don't take it seriously.
-
But certainly, of all
the diseases I've seen,
-
I think many of my colleagues
who are much older than me
-
and have memories of other outbreaks,
-
it's the scariest thing we've seen
in terms of the impact it could have,
-
and I think we need to respond to that.
-
CA: It's the scariest disease you've seen.
-
Wow.
-
I've got some questions for you
from my friends on Twitter.
-
Everyone is obviously
superexercised about this topic.
-
Hypothetically,
-
if everyone stayed home for three weeks,
-
would that effectively wipe this out?
-
Is there a way to socially
distance ourselves out of this?
-
AK: Yeah, I think in certain countries
with reasonably small household sizes,
-
I think average in the UK, US
is about two and a half,
-
so even if you had a round of infection
within the household,
-
that would probably stamp it out.
-
As a secondary benefit,
-
you may well stamp out
a few other infections too.
-
Measles only circulates in humans,
-
so you may have some knock-on effect,
-
if, of course, that were
ever to be possible.
-
CA: I mean, obviously that would be
a huge dent to the economy,
-
and this is in a way almost, like,
one of the underlying challenges here
-
is that you can't optimize public policy
-
for both economic health
and fighting a virus.
-
Like, those two things are,
to some extent, in conflict,
-
or at least, short-term
economic health and fighting a virus.
-
Those two things are in conflict, right?
-
And societies need to pick one.
-
AK: It is tough to convince
people of that balance,
-
the thing we always say
of pandemic planning
-
is it's cheap to put
this stuff in place now --
-
otherwise, you've got to pay for it later.
-
But unfortunately,
as we've seen with this,
-
that a lot of early money
for response wasn't there.
-
And it's only when it has an impact
and when it's going to get expensive
-
that people are happy to take
that cost on board, it seems.
-
CA: OK, some more Twitter questions.
-
Will the rising temperature
in coming weeks and months
-
slow down the COVID-19 spread?
-
AK: I haven't seen any convincing evidence
-
that there's that strong pattern
with temperature,
-
and we've seen it for other infections
that there is this seasonal pattern,
-
but I think the fact
we're getting widespread outbreaks
-
makes it hard to identify, and of course,
-
there's other things going on.
-
So even if one country doesn't have
as big an outbreak as another,
-
that's going to be influenced
by control measures,
-
by social behavior, by opportunities
and these things as well.
-
So it would be really reassuring
if this was the case,
-
but I don't think
we can say that just yet.
-
CA: Continuing from Twitter,
-
I mean, is there a standardized
global recommendation
-
for all countries
-
on how to do this?
-
And if not, why not?
-
AK: I think that's what
people are trying to piece together,
-
first in terms of what works.
-
It's only really in the last
sort of few weeks
-
we've got a sense that this thing
can be controllable
-
with this extent of interventions,
-
but of course, not all countries
can do what China have done,
-
some of these measures
-
incur a huge social, economic,
psychological burden
-
on populations.
-
And of course, there's the time limit.
-
In China, they've had six weeks,
-
it's tough to maintain that,
-
so we need to think of these tradeoffs
-
of all the things we can ask people to do,
-
what's going to have the most impact
on actually reducing the burden.
-
CA: Another question:
-
How did this happen
and is it likely to happen again?
-
AK: So it's likely that this originated
with the virus that was circling in bats
-
and then probably made its way
through another species
-
into humans somehow,
-
there's a lot of bits
of evidence around this,
-
there's not kind of single, clear story,
-
but even for SARS, it took several years
-
for genomics to piece together
the exact route that it happened.
-
But certainly, I think it's plausible
that it could happen again.
-
Nature is throwing out
these viruses constantly.
-
Many of them aren't
well-adapted to humans,
-
don't pick up,
-
you know, there may well have been
a virus like this a few years ago
-
that just happened to infect someone
-
who just didn't have any contacts
and didn't go any further.
-
I think we are going to face these things
-
and we need to think
about how can we get in early,
-
at the stage where we're talking
small numbers of cases,
-
and even something like this
is containable,
-
rather than the situation we've got now.
-
CA: It seems like
this isn't the first time
-
that a virus seems to have emerged
from, like, a wild meat market.
-
That's certainly how
it happens in the movies. (Laughs)
-
And I think China has already taken
some steps this time
-
to try to crack down on that.
-
I think that's potentially
quite a big deal for the future
-
if that can be properly maintained.
-
AK: It is, and we saw, for example,
-
the H7N9 avian flu,
-
over the last few years, in 2013,
it was a big emerging concern
-
and China made a very extensive response
-
in terms of changing
how they operate their markets
-
and vaccination of birds
-
and that seems
to have removed that threat.
-
So I think these measures can be effective
if they're identified early on.
-
CA: So talk about vaccinations.
-
That's the key measure, I guess,
-
to change that susceptibility
factor in your equation.
-
There's obviously a race on
to get these vaccinations out there,
-
there are some candidate
vaccinations there.
-
How do you see that playing out?
-
AK: I think there's certainly some
promising development happening,
-
but I think the timescales of these things
-
are really on the order
of maybe a year, 18 months
-
before these things be widely available.
-
Obviously, a vaccine has to go
through these stages of trials,
-
that takes time,
so even if by the end of the year,
-
we have something
which is viable and works,
-
we're still going to see a delay
before everyone can get ahold of it.
-
CA: So this really puzzles me, actually,
-
and I'd love to ask you
as a mathematician about this as well.
-
There are already several companies
-
believing that they have
plausible candidate vaccines.
-
As you say, the process
of testing takes forever.
-
Is there a case that we're not
thinking about this right
-
when we're looking at the way
that testing is done
-
and that the safety calculations are made?
-
Because it's one thing
if you're going to introduce
-
a brand new drug or something --
-
yes, you want to test to make sure
that there are no side effects,
-
and that can take a long time
-
by the time you've done all
the control trials and all the rest of it.
-
If there's a global emergency,
-
isn't there a case,
-
both mathematically and ethically,
-
that there should just be
a different calculation,
-
the question shouldn't be
-
"Is there any possible case
where this vaccine can do harm,"
-
the question surely should be,
-
"On the net probabilities,
-
isn't there a case
to roll this out at scale
-
to have a shot at nipping
this thing in the bud?"
-
I mean, what am I missing
in thinking that way?
-
AK: I mean, we do see that
in other situations,
-
for example, the Ebola vaccine in 2015
-
showed, within a few months,
very promising evidence
-
and interim results of the trial in humans
-
showed what seemed very high efficacy.
-
And even though
it hadn't been licensed fully,
-
it was employed for what is known
as compassionate use
-
in subsequent other outbreaks.
-
So there are these mechanisms
-
where vaccines can be
fast-tracked in this way.
-
But of course, we're currently
in a situation where we have no idea
-
if these things will do anything at all.
-
So I think we need
to accrue enough evidence
-
that it could have an impact,
-
but obviously, fast-track that
as much as possible.
-
CA: But the skeptic in me
still doesn't fully get this.
-
I don't understand
-
why there isn't more energy
behind bolder thinking on this.
-
Everyone seems, despite the overall risk,
-
incredibly risk-averse
about how to build the response to it.
-
AK: So with the caveat that,
-
yeah, there's a lot
of good questions on this,
-
and some of them are slightly
outside my warehouse,
-
but I agree that we need to do more
to get timescales out.
-
The example I always quote
-
is it takes us six months
to choose a seasonal flu strain
-
and get the vaccines out there to people.
-
We always have to try and predict ahead
which strains are going to be circulating.
-
And that's for something
we know how to make
-
and has been manufactured for a long time.
-
So there is definitely more
that needs to be done
-
to get these timescales shorter.
-
But I think we do have to balance that,
-
especially if we're exposing
large numbers of people to something
-
to make sure that we're confident and safe
-
and that it's going to have
some benefit, potentially.
-
CA: And so, finally,
-
Adam, I guess going into this --
-
There's another set of infectious things
happening around the world
-
at the same time,
-
which is ideas and the communication
around this thing.
-
They really are two very dynamic
interactive systems of infectiousness --
-
there's some very damaging
information out there.
-
Is it fair to think of this as battle
of credible knowledge and measures
-
against the bug,
-
and just bad information --
-
You know, part of what
we have to think about here
-
is how to suppress one set of things
and boost the other, actually,
-
turbocharge the other.
-
How should we think of this?
-
AK: I think we can definitely think of it
almost as competition for our attention,
-
and we see similarly, with diseases,
-
you have viruses competing
to infect susceptible hosts.
-
And I think we're now seeing,
-
I guess over the last few years
with fake news and misinformation
-
and the emergence of awareness,
-
more of a transition
-
to thinking about how do we
reduce that susceptibility
-
if we have people that can be
in these different states,
-
how can we try and preempt
better with information.
-
I think the challenge
for an outbreak is obviously,
-
early on, we have
very little good information,
-
and it's very easy for certainty
and confidence to fill that vacuum.
-
And so I think that is something --
-
I know platforms are working
on how can we get people exposed
-
to good information earlier,
-
so hopefully protect them
against other stuff.
-
CA: One of the big unknowns to me
in the year ahead --
-
let's say that the year ahead includes
many, many more weeks,
-
for many people,
-
of actually self-isolating.
-
Those of us who are lucky enough
to have jobs where you can do that.
-
You know, staying home.
-
By the way, the whole injustice
of this situation,
-
where so many people can't do that
and continue to make a living,
-
is, I'm sure, going to be
a huge deal in the year ahead
-
and if it turns out that death rates
are much higher in the latter group
-
than in the former group,
-
and especially in a country like the US,
-
where the latter group
doesn't even have proper health insurance
-
and so forth.
-
That feels like right there,
that could just become a huge debate,
-
hopefully a huge source
of change at some level.
-
AK: I think that's an incredibly
important point,
-
because it's very easy --
-
I similarly have a job
where remote working is fairly easy,
-
and it's very easy to say
we should just stop social interactions,
-
but of course, that could have
an enormous impact on people
-
and the choices and the routine
that they can have.
-
And I think those do need
to be accounted for,
-
both now and what the effect
is going to look like
-
a few months down the line.
-
CA: When all's said and done,
-
is it fair to say that the world has
faced, actually, much graver problems
-
in the past,
-
that on any scenario,
-
it's highly likely that at some point
in the next 18 months, let's say,
-
a vaccine is there and starts
to get wide distribution,
-
that we will have learned
lots of other ways to manage this problem?
-
But at some point, next year probably,
-
the world will feel like
it's got on top of this
-
and can move on.
-
Is that likely to be it,
-
or is this more likely to be,
you know, it escapes,
-
it's now an endemic nightmare
that every year picks off far more people
-
than are picked off by the flu currently.
-
What are the likely ways forward,
-
just taking a slightly longer-term view?
-
AK: I think there's plausible ways
you could see all of those
-
potentially playing out.
-
I think the most plausible is probably
that we'll see very rapid growth this year
-
and lots of large outbreaks
that don't recur, necessarily.
-
But there is a potential
sequence of events
-
that could end up with these kind of
multiyear outbreaks in different places
-
and reemerging.
-
But I think it's likely we'll see
-
most transmission concentrated
in the next year or so.
-
And then, obviously,
if there's a vaccine available,
-
we can move past this,
and hopefully, learn from this.
-
I think a lot of the countries
that responded very strongly to this
-
were hit very hard by SARS.
-
Singapore, Hong Kong,
that really did leave an impact,
-
and I think that's something
they've drawn on very heavily
-
in their response to this.
-
CA: Alright.
-
So let's wrap up maybe by just
encouraging people
-
to channel their inner mathematician
-
and especially think
about the opportunities,
-
and the transmission probabilities
that they can help shift.
-
Just remind us of the top
three or four or five or six things
-
that you would love to see people doing.
-
AK: I think at the individual level,
just thinking a lot more
-
about your interactions
and your risk of infection
-
and obviously, what gets onto your hands
-
and once that gets onto your face,
-
and how do you potentially
create that risk for others.
-
I think also, in terms of interactions,
-
with things like handshakes
and maybe contacts you don't need to have.
-
You know, how can we get those down
as much as possible.
-
If each person's giving it
to two or three others,
-
how do we get that number
down to one, through our behavior.
-
And then it's likely that we'll need
some larger-scale interventions
-
in terms of gatherings, conferences,
-
other things where
there's a lot of opportunities
-
for transmission.
-
And really, I think that combination
of that individual level,
-
you know, if you're ill
or potentially you're going to get ill,
-
reducing that risk,
-
but then also us working together
-
to prevent it getting
into those groups who,
-
if it continues to be uncontrolled,
-
could really hit some people
very, very hard.
-
CA: Yeah, there's a lot of things
-
that we may need
to gently let go of for a bit.
-
And maybe try to reinvent
the best aspects of them.
-
Thank you so much.
-
If people want to keep up with you,
-
first of all, they can follow you
on Twitter, for example.
-
What's your Twitter handle?
-
AK: So AdamJKucharski, all one word.
-
CA: Adam, thank you so much
for your time, stay well.
-
AK: Thank you.
-
(Music)
-
CA: Associate professor
and TED Fellow Adam Kucharski.
-
We'd love to hear what you think
of this bonus episode.
-
Please tell us by rating
and reviewing us in Apple Podcasts
-
or your favorite podcast app.
-
Those reviews are influential, actually.
-
We certainly read every one,
-
and truly appreciate your feedback.
-
(Music)
-
This week's show was produced
by Dan O'Donnell at Transmitter Media.
-
Our production manager
is Roxanne Hai Lash,
-
our fact-checker, Nicole Bode.
-
This episode was mixed by Sam Baer.
-
Our theme music
is by Allison Layton-Brown.
-
Special thanks to my colleague
Michelle Quint.
-
Thanks for listening to the TED Interview.
-
We'll be back later this spring
-
with a whole new season's worth
of deep dives with great minds.
-
I hope you'll enjoy them
whether or not life is back to normal.
-
I'm Chris Anderson,
-
thanks for listening and stay well.