and the disease it causes, COVID-19,

is spreading across the globe.

And as more cases appear outside of Asia,

you're probably starting to hear the word 'pandemic.'

- The risk of a global pandemic is very much upon us.

- [Reporter] Global pandemic.

- Could become a pandemic.

- [Reporter] With the potential to become a pandemic.

- Let's unpack what that word actually means

and how you can protect yourself going forward.

[light ambient music]

So, what is a pandemic?

Simply put, a pandemic is a disease that spreads globally,

crossing international boundaries

and affecting a large number of people.

To put that in context,

here are a few other helpful definitions.

So, firstly, we have this definition of an endemic disease.

That means a disease that's occurring

at a steady, predictable rate.

Then you have outbreak, which means a disease

that's spreading well above and beyond endemic levels.

An epidemic, on the other hand,

is an outbreak that's spread to a large geographical area.

Keep in mind that one disease can change status over time.

Now, going back to the P-word,

the classical definition of a pandemic

doesn't say anything at all about disease severity.

It's really all focused on geographic scale.

So far, the World Health Organization

hasn't referred to this as a pandemic--

- Our message continues to be

that this virus has pandemic potential.

- Although many epidemiologists,

myself included, are treating it as one.

The spread of this new virus, SARS-CoV-2,

is likely past the point of containment,

and that's the first thing you try to do

with a potential pandemic.

It's what China was trying to do with massive quarantines,

the likes of which we've never seen before.

But once you're past that point of containment,

you need to quickly pivot to another focus.

Instead of trying to stop a disease

that's already spread to many different countries,

you need to focus on slowing the spread of infection.

To do this, you have to properly isolate

people who are infected

and try and quickly develop treatments and vaccines.

It looks at least so far with this new virus

that the death rate is a lot lower

than other severe coronaviruses.

That doesn't mean many people haven't died.

We've seen thousands of deaths.

But the overall death rate is closer to around 3%

for this new virus,

whereas the death rate for SARS was around 10%,

and for MERS the death rate was over 30%.

Now, just because this new virus

doesn't seem to have as high a death rate,

it doesn't mean that we shouldn't have a plan.

So, how do we protect ourselves right now?

I know this sounds really pedestrian,

but trust me, one of the best pieces of advice

is to wash your hands with soap and water regularly,

have good cough hygiene, so cough into your elbow,

cough into a tissue and then throw it away,

and also get your flu shot.

I know people are kinda over

hearing about the flu at this point, but the reason I say it

is that if you get sick with the flu,

it massive increases your risk

of getting a second respiratory infection

like the new coronavirus.

Also, you can practice what's known as social distancing.

That means simply limiting your exposure to other people

by working at home, for example,

or if you're in public, maintaining a distance

of three to six feet between you and others.

I'm getting a ton of questions about masks, understandably.

So, here's what you need to know.

You need to wear a mask

if you have symptoms of respiratory disease,

symptoms like coughing,

or if you're looking after people who are sick

and have those symptoms.

You also need to know how to properly use a mask

and be aware of things like once a mask is moist,

it's not as effective and needs to be replaced.

Wearing a mask without full knowledge

of when and how to wear it can be dangerous

because it gives people a false sense of security

about how protected they really are.

If you do need a mask,

health authorities recommend a regular surgical mask

because that prevents droplets from other people

coming into contact with your mouth and nose.

And if you have symptoms,

it prevents those droplets from you reaching others.

An N95 mask is recommended for healthcare workers

caring for sick people when they're doing procedures

that bring more fluid up from inside a person's lungs.

That's more dangerous,

so that's why an N95 mask is recommended.

Bear in mind that with masks, it's not one-size-fits-all.

You wanna make sure that a mask you're wearing

really is right for you and really is working.

One way to do this, ideally you get fit-tested,

but also when you put an N95 mask on,

you can do a seal test where you breathe hard

and you feel to see whether any air

is escaping around it or not.

A question I get asked a lot

is should you wear a mask if you don't have any symptoms

just to be really, really safe.

The answer I normally give is no

because if you wear a mask unnecessarily

or you stock up on a ton of them,

you're just contributing to the mask shortages

that we're already seeing

and taking away resources from people who truly need them.

So, for now, take advice

from what your local health officials are saying.

I think what history tells us

is that pandemics are inevitable and to be expected,

and that's why we really need

solid pandemic preparedness plans at national levels

and also at family and community levels.

To understand just what pandemics are capable of,

let's look at a few examples from human history,

starting with perhaps the most infamous pandemic,

the Black Death or the bubonic plague.

Now, this pandemic got its name from its symptoms,

specifically lymph nodes that became blackened and swollen

after bacteria entered through the skin.

Lovely, I know.

Now, this isn't the first pandemic, by any means,

but it's certainly one of the deadliest.

It lasted from around 1346 to 1353

and resulted in the deaths

of somewhere between 75 million people

up to 200 million people.

It's mostly associated with Europe,

but it's thought to have originated in Asia

and then spread across that continent,

as well as possibly Africa.

There are a few theories

about how the disease spread to humans.

Some scientists say it could've spread to us

directly from rats.

Others say there's some evidence

that it was actually spread by fleas that lived on gerbils.

Let's fast-forward to 1918,

and here we run into the Spanish Flu pandemic,

which infected one in three humans alive at the time

and killed about 50 million globally.

It's only called Spanish

because Spain was not involved in World War I

and it was neutral.

Therefore, it did not have news censorship.

So, when this outbreak arrived in Spain,

that's when it got press coverage,

whereas in France and other countries

it was not mentioned in newspapers at all.

The Spanish Flu killed really quickly.

There were approximately 25 million deaths

in just the first five or six months.

Part of the reason for that though

probably had to do a lot with poor living conditions

at the time and the fact that flu makes you susceptible

for other infections like bacterial chest infections,

and back then there were no antibiotics.

And unlike what we're seeing today,

where it seems that older people

are more vulnerable to death from COVID-19,

at least based on preliminary data,

Spanish Flu was different.

It was wiping out young and healthy adults.

Then there's the HIV/AIDS pandemic.

HIV quickly spread from Central and Western Africa

to every continent on the planet in the early-1980s

and it's killed more than 30 million people

around the world.

It's also the first pandemic

for which there's been global activism

and the very rapid development of treatments.

It went through the whole spectrum,

from being an outbreak to an epidemic to a pandemic,

and now many people say we can call HIV endemic

in some parts of the world.

Thanks to advances in medical technology

and the AIDS activists,

HIV should be a chronic manageable condition

that you live with your whole life,

although ideally we'd have a vaccine and a cure for HIV.

Next, we have the SARS pandemic,

which went from 2002 to 2003

and was also caused by a coronavirus.

Remember, that's a whole family of viruses,

including four coronaviruses that cause the common cold,

as well as this new coronavirus that causes COVID-19.

SARS likely jumped from civet cats to humans in China

and then spread to other parts of the world.

Back in 2002, Chinese officials had a delay

in sharing data about SARS.

And in the response, the World Health Organization

updated the international health regulations,

basically to compel all 194 member-states

to get their act together and meet specific standards

for detecting, reporting, and responding to outbreaks.

These new plans for a more coordinated global response

to pandemics came into effect

with the 2009 Swine Flu pandemic,

which was caused by a new H1N1 flu virus

and killed between 150,000 to around half-a-million people.

It spread really widely.

It was seen in both Northern and Southern Hemispheres

between April and September of 2009,

which means it also spread

outside of the normal flu seasons.

We've learned from previous pandemics

that people can either day from the disease at hand

or develop immunity to that disease.

And that means that as the disease continues to circulate,

it won't have that same devastating impact

that it did the first time around.

One example of this is the H1N1 virus

that caused the 2009 flu pandemic.

That virus is now a common flu virus

that circulates worldwide, but it doesn't cause a pandemic.

So, how does a pandemic end?

Virologists estimate that this new virus

will likely stay in China

and continue to seed other countries and the world

until maybe it just becomes as common

as the other four coronaviruses

that cause the mild common cold.

Some people are even starting to call it

the fifth coronavirus, so maybe that will be its story.

It goes from COVID-19, which caused this terrible situation,

to the fifth regular coronavirus causing the cold.

Some virologists even predict

that maybe 40% to 70% of adults around the world

will become infected with the new virus

before this is all over.

But many scientists still say

the vast majority of those who become infected

are more likely to have a milder version of the disease.

What we have on our side versus those poor people

facing the Black Death, for example,

is we have the capacity to more quickly develop