What if I told you that 8% of your DNA isn’t actually yours. What if
I said it was given to you by a strange, almost alien lifeform,
one that still lives amongst us right now. Don’t worry, I’ll explain all in just a minute.
But first, I want to ask you a question. Imagine you wake up tomorrow and turn on the TV to be
shocked by the breaking news that every virus in the world has been eradicated. How would you feel?
I’m willing to bet you’d be somewhat elated. In an instant you’d be free of the fear you’ve
held in the back of your throat your entire life - that you could catch a killer virus,
Ebola, HIV, Influenza, the list goes on. You might merrily skip outside and
give the pavement a good lick, and maybe your neighbour’s face for good measure,
safe in the knowledge that no ill can come of your wreckless lick-a-thon.
But what if I told you that your relief would be replaced with dread in the coming years,
as a series of unexpected, but deadly consequences arise amidst this new
virus-free world. What if I told you that you’d soon be begging for the return of
those once-maligned pathogens? Don’t believe me? Watch until the end of this video and
you’ll discover why eradicating viruses could be the biggest and last mistake we ever make.
Viruses are everywhere. And I don’t mean like Pret-a-Mangers in London everywhere. I mean
that viruses literally cover every inch of our world. From the deepest depths of the ocean to
the highest mountain peak, and from the most barren deserts to the densest rainforests,
there is no corner of our planet where viruses cannot be found.
They’re in every breath you take. Korean scientists tested the air in a forest and
found that each cubic metre of air contained up to 40 million viruses.
That fact might make you feel icky and only give rise to your desire to eradicate them
from our planet. But don’t be so hasty - you should be grateful for those gross organisms
to which you are playing host, because without them, you probably wouldn’t be here right now.
In the grand tapestry of life, viruses have been not just a thread, but a master weaver,
intricately shaping the very fabric of our existence. It's a story that
begins at the dawn of life itself, in the murky, primordial waters of ancient Earth.
Viruses, in their simplest form, are genetic material encased in a protein coat. They are
so primitive that they straddle the line between living and nonliving, unable to reproduce without
a host. This ancient survival mechanism suggests that viruses may have been among the first forms
of genetic material, possibly co-evolving with the earliest forms of cellular life.
In Earth’s early life soup, viruses played a unique role. Gene mutations can happen vertically,
when genes are passed from parent to offspring, but viruses are special,
in that they enable horizontal gene transfer.
Think of them as couriers, carrying tiny packages of genetic information from one host
to another. This process would have catalysed the evolution of early organisms increasing
the diversity and speed of the evolution process. And this same process went on to
effect the evolution of larger organisms, such as insects and animals, later in Earth’s timeline.
The evidence of viruses' ancient origins and their role in shaping life is etched
into our very DNA. I mentioned at the start of this video that 8% of your DNA is not
yours - that 8% is composed of endogenous retroviruses, remnants of ancient viral
infections. Viruses have made us who we are today - we don’t know how humans would have
turned out without viruses, but we'd be radically different, if we existed at all.
And it’s not just animal life that has reaped the benefit of what viruses have sown. They’ve played
a pivotal role in the evolution of plants. Plant viruses have been shown to confer resistance to
certain pests and diseases, improving crop resilience. Without this, modern day plants
might be too weak to survive in our changing world and we might have succumbed to a famine by now.
So, by this point, I’m probably changing your view a little on viruses - but let’s still
answer the question, what would we have to do to eradicate them, and what would happen if we did?
Let's start with the how. Eradicating all viruses would be an undertaking of unprecedented scale
and complexity. It's not just about developing a cure or vaccine for every known virus - which
in itself is a close-to-impossible task. No, it's about completely removing every
single viral particle from every corner of the planet. From the depths of the oceans
to Taylor Swift’s underwear drawer - that’s right, it’s going to be a huge challenge.
Imagine nanobots capable of identifying and destroying viruses at a molecular level or
perhaps some form of global atmospheric filtration system that could remove viral
particles from the air. We'd need similar systems for water and soil. Then we’d need to
purify every living organism, which could be done using a mythical super vaccine,
providing we wait a generation for all the current carriers to die off.
Even if we could develop a universal vaccine for every known virus it wouldn’t even scratch
the surface. For a start we only know about a fraction of them, highly-speculative estimates
put the number at about 1% - so 99% of all viruses are unknown to science. Then there’s the fact
that viruses evolve constantly and rapidly. Besides, say you had this magical vaccine,
how the holy hell are we going to inoculate every living thing? It’s not just humans,
everything would need to be inoculated, and I mean everything. Can you imagine
trying to chase down twenty-million ferrets to stab them with needles?
If such a vaccine was created, let's just assume that it can adapt itself
to all unknown and future strains of viruses. The most effective method of disseminating it
would be by spreading it throughout the global water supply - that way it would
eventually make its way into the water cycle and rain down on crops, which would be eaten,
directly or indirectly, by almost every living creature. This is obviously grossly
oversimplified and the reality of such an operation would be insurmountably complex.
But let’s say, for argument’s sake, that we manage the impossible. We inoculate every living
creature. We get out the Dettol and scrub every rock and every leaf. We purify every particle
of air using the most advanced graphene filter imaginable. You get the idea… after doing all
of this, and a lot more besides, planet Earth is officially, 100% virus-free. What happens next?
It would be an appropriate metaphor to say in doing this our species has
now crossed the Rubicon, because for reasons that will soon become clear,
there is no turning back. We have no choice but to march on a squeaky-clean Rome,
but what will be awaiting us? Will it be a virus-free utopia, or a vision of hell?
Initially it might seem like heaven. Imagine waking up in a world where the
constant threat of viral pandemics no longer looms over humanity - the news might have to
talk about something interesting for a change. Hospitals and healthcare systems
would be relieved of a significant portion of their cases - no more HIV,
flu or hepatitis. This would potentially have the added benefit of reduced taxes.
The psychological impact would be profound. Without fear of contracted
illness socialising would feel easier and physical contact would be employed more
liberally - just imagine being able to take the tube without
worrying if every ruddy-faced traveller around you is carrying a dreaded cold.
People would take fewer sick days, resulting in
a worldwide uptick in productivity. Without livestock contracting viruses
the global food supply would become more stable and slightly cheaper.
And perhaps the greatest benefit would be that without viruses to worry about,
medical research could re-focus all of its attention onto curing non-viral killers,
such as cancer, dementia and other genetic diseases.
But as the initial wave of euphoria fades, cracks begin to appear in our
virus-free utopia. The first sign of trouble comes from the natural world.
Without viruses to keep their populations in check, certain species of bacteria start
to proliferate uncontrollably. These bacteria, once harmless, become opportunistic pathogens,
causing outbreaks of diseases we've never seen before. Our antibiotics,
already stretched thin by years of overuse, prove to be ineffective against these new threats.
In the oceans, the absence of marine viruses destroys the marine food web. To give you
some kind of idea, every day viruses kill about 20% of all bacteria in the ocean,
and all that dead bacteria provides a food source for microscopic marine life - and that’s
a delicate balance you just don’t want to upset. Phytoplankton, usually kept in check by viruses,
now bloom uncontrollably, leading to the depletion of the ocean's oxygen,
creating vast dead zones where no fish can survive. Suddenly,
a primary source of protein for billions of people around the globe is threatened.
Furthermore, phytoplankton acts like a carbon sponge, absorbing CO2 from the
atmosphere. Therefore, a huge algae bloom could reverse the greenhouse gas effect,
causing the climate to rapidly cool. Some of you might think that’s a good thing,
after all, isn’t that what every politician and Swedish teenager has been banging on about
all this time? Well not quite. Because not only would the algae absorb CO2,
it would also increase the albedo, that’s the reflectivity, of the Earth’s surface. Which means
more solar energy would be bounced back into space, so the Earth absorbs less of the sun’s
heat. The result could be a runaway cooling event, paving the way for another ice age.
On land, ecosystems begin to unravel in alarming ways. Insects, crucial for the
pollination of countless plant species, are severely impacted. Without viruses
to naturally regulate their populations, species like the aphid explode in numbers,
leading to widespread crop damage and a disruption in the natural food chain.
In humans, the consequences are equally dire. Our immune systems,
having evolved in a world teeming with viruses, begin to malfunction. Without viruses to train
and regulate our immune responses, we see a rise in autoimmune diseases. Our bodies,
lacking an external enemy, will start to attack themselves. Conditions like multiple sclerosis,
rheumatoid arthritis, and type 1 diabetes become rampant.
You’ve heard of the human microbiome, but have you heard of the virome? There are strains of
viruses inside you and on your skin right now that have been with you your entire life - your
silent passengers. We think of viruses as bad, but most of the viruses in your
virome are harmless and are even beneficial. They influence your microbiome and complement
your immune system by reducing populations of pathogenic bacteria and harmful viruses in your
body. Getting rid of your virome would have profound and untold consequences.
But the most alarming effect, at least long term, comes in the form of genetic stagnation. We think
of evolution as a slow process, taking place over millions of years. But a significant and
sudden change in the environment, like removing all viruses, would cause all living things to
exhibit noticeable changes within just a century or two. Animals with shorter life
spans would be the first to exhibit change. But, given enough time, human DNA would also
adapt. Future generations are born into a world where genetic diversity is severely stagnated,
making our species more susceptible to new diseases and environmental changes.
In a cruel twist of fate, humanity realises that in its quest to create a virus-free utopia,
it has instead fashioned a fragile world teetering on the brink of ecological and genetic collapse.
The irony is not lost: in our attempt to outsmart nature, we have underscored our own vulnerability.
And, in pursuing a perfect world, we lose sight of the imperfection that made our world perfect.
As I already mentioned, scientists think that viruses have been on earth since the dawn of
life - so, to boil it all down, we just shouldn’t mess with what’s worked for billions of years.
OK, we’ve screwed up. Crop failures are leading to mass famine,
we’ve just triggered a new ice age and our bodies are attacking themselves. Can’t
we simply tuck our tail between our legs and retreat back over the rubicon? Can’t
we simply re-introduce viruses and hope ecological balance is restored?
Well, there’s a reason I described eradicating all viruses as “crossing the Rubicon”. Because
there is no way back. At least, there is no easy way - especially if we’re sans viruses
for a prolonged period of time, the longer it is the worse it will be upon their return.
It's not just a matter of sprinkling viruses back into the atmosphere and the oceans. The
ecological systems, having developed for decades without these viral regulators,
are no longer prepared for their reintroduction.
For instance, if we were to reintroduce viruses that previously controlled aphid populations,
aphids, now with weakened immune systems, might experience mass die offs - and that
would be bad. Although a pest, they provide a vital food source for many small predators.
A similar outcome could happen in the oceans. Phytoplankton populations, having bloomed
uncontrollably, might collapse suddenly, leading to a catastrophic breakdown of the
marine food web. The climate - having cooled - would now shoot in the other
direction without phytoplankton to suck up CO2. Triggering a runaway global warming event.
The global agricultural system, already reeling from pollinator collapse and crop failures,
would have to adapt yet again to a new set of challenges. Healthcare systems worldwide,
already burdened by a rise in autoimmune diseases, would have to deal with a new
wave of viral illnesses. And that’s only the beginning as far as us humans are concerned.
Decades without viral-mediated gene transfer have left all species,
including us, with reduced genetic diversity and untrained immune systems. Especially for
the next generation - in the 1980s the hygiene hypothesis was formulated that states babies who
aren’t introduced to pathogens will grow up with severely weakened immune systems,
and at a greater risk of allergies and other autoimmune diseases - it’s the classic,
a little dirt never hurt anyone argument. Reintroducing viruses into such a population
could be disastrous. Viruses that were once relatively harmless could become lethal. It
would be reminiscent of when the Spanish brought Smallpox to the New World. If you
thought coronavirus wreaked havoc in 2020 - just wait and see what happens when a similar
virus is let loose on a population whose immune systems have just awoken from a 100-year siesta.
Lastly, I just want to point out that a lot of the hypothetical scenarios I mentioned in this
video are highly speculative, despite being drawn from current scientific understanding.
Did you know that viruses are, by far, the most abundant biological entity on earth? Trying to
predict what would happen if we removed them from our world, and then reintroduced them,
is such a dense and complex task that there is no supercomputer or AI model in existence
that could attempt to do it. For everything that is affected by viruses - biology, the climate,
evolution - there are a hundred other contributing factors. Viruses are just too intrinsically woven
into the makeup of our planet and our history and the history of every living thing. All I do know
is that we should wish for their removal at our peril. Except for SARS-COV, that can fuck off.