Hello, I'm Paul Richards.
In this episode of THE LATEST SCIENCE, we speak to Academy Fellow Professor Eddie Holmes
from the University of Sydney,
His work focuses on the evolution and emergence of infectious diseases, particularly the mechanisms
by which viruses jump species.
He's been at the forefront of work aimed at understanding how that happened with COVID-19.
Eddie, thanks for being with us.
We've heard a lot of speculation about the origins of this virus.
What do we know for sure?
So
we know that this virus was most likely present in animal populations in China. We
think the most likely animal that it would have started off in would have been bats.
We know that bats carry other coronaviruses and then it probably, can't be sure but we
think it probably jumped from a bat into another animal and that other animal was probably
near a human, maybe in some sort of market situation. And so we're not sure what that
intermediate animal species is yet. That needs to be kind of looked at further, but maybe
that intermediate animal species in a market then passed the virus to humans and that's
how it's kind of started spreading, probably in Wuhan and then it's gone global.
Now some reports have pointed the finger at wet markets. For those unfamiliar, what is
a wet market and do you think that they are part of the problem?
Yeah, so wet markets, and I visited markets like this a number of times. They're markets
where you find live animals being sold.
So you go to these markets, you find different mammalian species in cages
kind of stacked next to each other or on the floor. And so the people working in the market
are directly next to and working with wildlife. That's the critical thing: these are wildlife.
They're not farmed animals, they're not domestic animals, these are wildlife animals. And so
the problem is that obviously if that wildlife animal has a virus it's picked up from a bat
itself and we're interacting with them in the market situation, there's a good chance
that the virus will then spread to the person handling the animal and that person will then
go home and then spread it to someone else and et cetera and we have an outbreak, and
that's kind of what we think most likely happened here.
How does a virus like COVID-19 actually get transferred from another animal to a human?
I mean, is that common?
Yeah. So obviously, we don't know exactly what happened in this case and we may never
know exactly the precise chain of events of what happened. What we suspect happened, a
good kind of model, is that someone in a market situation would have been handling an animal
and that animal would have had maybe a respiratory secretion that would have a virus in that.
Like we have the virus in humans, it's a nasal pharyngeal virus or respiratory virus. And
that could have also happened in the animals. It doesn't take much imagination that the
animal excretes that virus in respiratory fluid, the person then touches their hands,
they touch their nose et cetera et cetera. And then you have an outbreak. And again that's
just the model. We don't really know exactly what happened. And we may never really know
in detail, but those sorts of events seem very plausible. And so people handling wildlife
are always at risk of these sorts of infections. So very simple things. We need to take great
care when we handle any wildlife species.
Is it common for viruses to be perhaps carried by or infecting another animal and then also
picked up by human? I'd also note that pets for example, seem not to be at risk from COVID-19
as far as we know. Is this kind of transfer between species common for viruses?
Yeah. So, viruses, RNA viruses particularly, viruses very commonly jump species boundaries,
it's their kind of general mode of life. That's what they want to do. So the virus wants to
find a new cell to infect and that cell can be in the same species or it can be in different
species. As long as it finds a kind of cell it can infect and replicate in, it's very,
very happy. And so what we found for many viruses is that they can very commonly jump
species boundaries. They're very happy to do that. And for some reason coronaviruses
are particularly good at infecting and jumping to multiple animal species. They do it all
the time. And myself and colleagues have sampled lots of coronaviruses from different populations
of animals. And we see jumping of species as a very, very regular occurrence. So I was
not at all surprised that this thing happened. We've been predicting this for a long time.
It really was something that was very clearly going to happen at some point. And it has
happened and it's just the way that these viruses are very able to jump species boundaries.
And of course the way humans live today, in this very big, connected, fluid world, they
can then, if they do get in to humans, they can spread very quickly to kind of pandemic
scale as has happened here.
As you mentioned, you know, health authority scientists have warned of this, something
like this could happen for a very long time. Now that it's happened in this way with COVID-19,
why do we seem to be underprepared to respond or is that the wrong way to characterise what's
happening?
I do think there was some complacency and I do think we were underprepared. I think
the real warning alarm bell was SARS in 2003 and it's a very analogous situation to here.
So in SARS what happened was again, it was a bat virus. We think the bat then passed
the virus to an animal called a civet, it's kind of a cat-like animal, then from a civet
into a human, again maybe in a market situation. So SARS should have told us then that we need
to reduce our exposure to these wild animals in market settings and kind of wildlife trade.
That's what we should have done. What we should also have done is started to make what's called
cross-protective vaccines or universal vaccines like the one they're proposing for influenza.
And those vaccines should be made for all the types of viruses we think can jump from
animals to humans like coronaviruses and the same way you want broad-acting antivirals
that can work against a range of viruses.
So what we should have done is stockpile those. And then when we get an outbreak, we can use
the ones we have ready. Now I say those words: make a universal vaccine, make broad protective
antivirals. It's very easy to say. Obviously it's very hard to do. I mean, we've spent
years making a universal flu vaccine, haven't quite got there yet, but we should have at
least started the research program on doing that. So SARS is 17 years ago. So after SARS
we didn't do that and there were very few people working on coronaviruses and very,
very few people, if any, work on coronavirus vaccines and that was a mistake. We did drop
the ball there. So clearly now though going forward, you can certainly expect there'll
be a huge effort to make these broadly protective vaccines and antivirals to stop it ever happening
again.
And
part of that complacency, do you think that we have seen how effective vaccines have been
over time? We know that we are now protected from many of the viruses and diseases that
have claimed thousands of millions of lives over time. And so it's quite a shock when
we have a virus like this suddenly reach the spread that it has.
Oh yeah. No, I think obviously it's shocked many people, but I think the thing to remember
about vaccines is they do take time to develop. Even now we're talking about next year realistically
for the vaccine.
We cannot
add a vaccine that's not going to work or even make things worse on top of already a
very major global health problem. So yes, vaccines are great, but they do take time.
That's why we need to preempt it for the future, have these sorts of universal vaccines ready,
right now that we can pull out of the freezer and use when necessary. So vaccines, they
have made us complacent. I think people don't realise how long it takes to really make a
vaccine to the point where you can clinically apply it to people in populations.
I'd like to just put to bed if you can, some of the theories that have been floating around
that this virus for instance, was manufactured in a lab as part of some kind of biological
warfare. Have you been able to prove that this is untrue?
Obviously people get very...when they see something so unusual
and so seemingly out of the blue, lots of strange theories naturally sort of appear.
I think there are a number of really clear reasons to believe this is not in any way
a lab construct or a lab escape. The key things are, all the component bits of this virus,
all the genes and bits, the proteins that make up the COVID-19 virus, they are all found
in natural animal species. There's nothing unusual about it. It has bits of what looks
like bits of bat virus, maybe pangolin virus. We know all the components are absolutely
mapped and they're also all natural ingredients. Also if someone was wanting to engineer a
coronavirus, what they would naturally do is take the standard laboratory strain that's
out there, of which there are a number of them, and they would manipulate a standard
laboratory strain and turn it into what they wanted. And that's not what's happened here.
This is not a standard laboratory strain. It looks for all the world, and I'm certain
it is, a natural coronavirus that's come from an animal in a natural setting. There's nothing
in there at all that is a signature of laboratory manipulation. So I think we can pretty safely
put those conspiracy theories to bed.
What have you learned so far about this pandemic and from it in reducing transmission of coronaviruses
from animals to people?
So this pandemic really has, I think for me, because I've been in this for a long time,
it's really just confirmed what I kind of suspected already and I knew already, that
the simplest way we can, as a species, stop these things happening again is to reduce
our exposure to wildlife populations. Okay. Particularly in these market situations, illegal
wildlife trading, we have to build simple barriers by, I will suggest, closing these
wet markets down, really stopping the trade in wildlife species. Now people argue, oh,
maybe it'll go underground. But anything that reduces the number of these and therefore
reduces the exposure of humans to wildlife viruses must be a good thing. And SARS told
us that, and this has told us that in an even more dramatic and stark fashion, and we have
to do this. And it's a very simple thing. It doesn't involve much money. It just involves
governments policing these markets and stopping our close interactions with wildlife. So that's
a very simple first step.
Okay. It's obviously going to be a long journey because these wet markets are
very common all over the world. But from a scientific point of view, you're saying that's
the area that needs to be addressed to stop this transmission from animals to humans then
that's a really interesting point. Now you've written a paper stating that coronaviruses
have the capacity to jump species boundaries and adapt. So is it likely that we will see
more pandemics like this in the future?
Yeah, I mean the way humans live today, really they are just perfect for pandemics to occur.
Like this particular one. So it happens in Wuhan, so it's a major city in China, a major
travel hub and it happens just before the Lunar New Year, where millions, literally
millions of people move around China that have returned home for the festival. And then,
of course China is a very well connected country, then it spreads globally. So the way we live
has just set it up for pandemics, our modern connect is what has set it up for pandemics
to occur. So we are living in an age where they are very likely, I mean we know that
wildlife species do carry lots of viruses. As I've said, hopefully though, hopefully
this will be the wake-up call we need for the world to change the way we live, to reduce
our interaction with wildlife species and to try and prepare ourselves. I mean really
people use the word prepare and its very glibly, but to do it absolutely properly and to have
good surveillance of animal populations or human populations and to stockpile those broadly
reacting vaccines and antivirals that we can just deploy when we need to, hopefully this
will be the wake up call for that.
Now you said that in terms of the exit strategy for this particular virus and how it's impacting
us at the moment, a vaccine won't be available until likely next year.
What is the exit strategy then?
Right, so the question is and what we mean by exit strategy is how do we.... We can reduce our transmission,
we will do at the moment because we're following physical distancing and that's going to be
a great thing, we all need to do that, that will reduce the number of cases in Australia
to get to a very, very low level, but that's going to happen long before the vaccine will
be available and moving to next year as you said for the vaccine. So what do we do in
that interim period? What's the best way of keeping case numbers low while we wait for
the vaccine to happen? And I, you know, there are many different suggestions how to best
do that. I'm not sure what the best one is. People would debate that. For me though, I
think what it must involve at some point is very, very heavy levels of testing. We can
really accurately track who has the virus and if we isolate them and we do that as frequently
as we can, across as broad a set of populations as we can, hopefully then we can track any
chains of transmission and quickly close them down. So I'm hoping testing, vigilance, isolation,
effect the populate, people or contacts, that may be enough to keep the levels very, very
low until the vaccine becomes online sometime next year.
Professor Edward Holmes, thank you very much for your time. My pleasure.
I'll be back on Friday with another edition of THE LATEST SCIENCE.
My guest then will be renowned immunologist, Professor Ian Frazer.
If you have questions you'd like him to answer, just leave them in the comments section below
this post.
I'm Paul Richards. See you on Friday.