Original subtitles

Mother Nature’s stealthiest killer

is the pandemic.

A worldwide spread of infectious disease,

it is a natural disaster for which we have some forewarning,

but this only makes it all the more terrifying.

With an ever more mobile world population,

potentially growing to 11 billion people

by the next century,

public health experts agree

that the possibility of a cataclysmic disease

spreading to all parts of the globe

is more likely now than ever before.

So, what makes pandemics different

from normal infectious diseases

is they’re generally new diseases

into human populations.

They emerge from, typically, wild animals,

through humans coming into contact with those animals.

And something critical needs to happen.

Those viruses, typically viruses,

are not well adapted to humans.

They mutate.

And then when that mutation happens,

they have to start spreading within the human population.

The outbreak needs to get to a certain scale,

and then it really takes off.

What happens when the amount of disease in a community

rises above the expected level for the population?

When there are more cases of infections in hospitals,

the regional authorities and also on the national levels

you have emergency plans to, essentially,

come up with ways to cope

with these increased numbers of people

who turn up at the hospitals.

A pandemic is a whole different thing,

and the main difference is that the virus strain

that hits the population in a pandemic year

is radically different from the virus strains

that had been circulating in the previous years.

The consequence of this is that the population

has no prior immunity

acquired through the previous exposure.

And therefore, the infection rates are just much higher,

and, uh, the number of infected people

that turn up in a hospital is much higher as well.

Among the most devastating pandemics in history

was the Black Death,

which killed at least 75 million people

throughout the 14th century.

By 1400,

it had killed more than 34 million European inhabitants,

or up to 50 percent of the entire population

on the continent.

It would be a mistake to believe that the modern world

isn’t susceptible to a similar kind of widespread outbreak.

With the advent of jet travel,

disease can be spread quite easily

and with terrible rapidity throughout the globe.

But it wasn’t always like this.

At the time of the Agricultural Revolution

roughly 10,000 years ago,

man turned from nomadic life as a hunter-gatherer,

and settled into large communities.

This caused the way that viruses interacted

with the human population to change dramatically.

Agricultural revolution essentially meant

that it became easier to produce food.

And when you can produce more food,

you can have more people living in the same space.

That means the population density goes up, and, um,

this is wonderful for infectious pathogens.

For a virus, it is extremely important

to have a sufficient number of potential victims around.

In a way, the Agricultural Revolution

made it much easier for infections

to go round and round and round and round

in populations in a way that wasn’t possible before.

So it was only when human societies

started having large groups of people,

after we could make our own food through agriculture,

and we started to have towns and cities,

that you got enough people together

to really sustain these sort of epidemic diseases

of the type we’re talking about.

One of the diseases

which has most frequently caused pandemics

to sweep the globe is influenza.

This is because the virus that causes the disease

regularly mutates into a form

for which the general population

has no natural immunity.

Historically,

a new mutated strain of the influenza virus

has appeared three or four times a century,

or roughly every 30 to 40 years.

In the last hundred years,

there have been four deadly flu pandemics.

The Spanish Flu pandemic,

occurring between 1918 and 1919,

may have killed at least 50 million people worldwide.

Astonishingly,

more soldiers died from the 1918 flu

than were killed in the entire war.

Adjusting for population growth,

the number of dead from the Spanish Flu

is equivalent to about 425 million people today.

The most recent influenza pandemic

was the global outbreak known as swine flu,

which occurred between 2009 and 2010.

The viruses that have mutated and caused these pandemics

typically originated from animal influenza viruses.

It is believed that they are bred

as a result of the interaction

between diseases among humans and animals.

In North America and Europe,

seasonal flus occur each autumn and winter.

As the majority of people

will have been exposed to these viruses

in previous seasons,

the symptoms are typically mild.

However, every 20 to 40 years,

the flu virus undergoes a dramatic mutation.

Viruses are parasitic. They’re not alive themselves.

They’re little chunks of genetic material

which modify the cells in our body.

Different viruses target different cells.

So the influenza virus, for instance,

targets certain cells,

basically in the lining of our respiratory system.

And when it enters through our mouth and nose

into our lungs, the virus will attach itself to cells,

enter cells through a complex set of molecular machinery

and then hijack the cellular machinery

to start creating copies of itself.

And those copies will burst out of that cell

into the mucus of our lungs,

and through the process of generating symptoms,

coughing, also gets expelled and move onto the next host.

The flu virus is highly contagious.

each time a sick person coughs,

they expel some 2000 virus-laden droplets.

Sneezing or even talking,

can also generate respiratory droplets.

If you inhale or touch any object

infected with these droplets

and rub your nose or eyes thereafter,

the virus can get through the mucus membranes in your mouth,

nostrils or eyes, and into your airways.

People can be infectious 24 hours

before they even feel ill,

and for five to seven days after they become sick.

Once the flu virus has gotten into your body,

it travels down your airways,

binding to the cells which line the lungs.

When a virus infects us,

there is a whole arsenal of countermeasures

that the organism has provided and is able to provide.

And two very important ones, called T cells

and the other ones, antibodies.

When we vaccinate people that is what we try to induce,

so that you have already T cells and antibodies

that are specific to a virus

that you may encounter later on.

So this is what we want from vaccines.

Most of the symptoms of the flu

are actually caused by what your body does

to try and fight off the virus.

It’s when the body’s cells are under attack

that your immune system kicks in.

Counteroffensive is led

by infection-fighting white blood cells

called T lymphocytes.

T lymphocytes, or T cells,

are often referred to as soldier cells.

In the specific case of the T cells,

one of the important mechanisms to eliminate the virus

is to essentially kill off infected cells.

There are ways to detect that a cell is infected.

And then they go there,

and they have mechanisms to kill off this cell.

This, of course, means there is collateral damage,

because the cell is now not there anymore.

We predominately feel influenza symptoms

in the respiratory system, in the lungs and throat,

because those are the cells the virus targets.

Although the influenza virus only stays in the lungs,

the symptoms of the illness can be felt all over the body.

These include fever, headache,

tiredness and aching muscles,

which is why the flu can make us feel so very ill.

So there are multiple things which cause symptoms

with an infectious disease,

partly it’s affected by the virus itself.

Viruses, as they replicate,

they infect lots of cells and cause damage to the person,

and fever is actually an adaptive response

to help us clear infection because most infections

are tuned to the body’s normal temperature.

By making us hot, the immune system

actually reduces how quickly bacteria and viruses replicate.

The immune system is trying to eliminate the virus,

the infected cells, from the body.

And by doing that, it damages us,

and that can generate inflammation,

can make us feel even sicker,

can, for instance, for flu, cause difficulty in breathing.

According to new estimates published in December of 2017,

between 291,000 and 646,000 people around the world

are killed each year

as a result of catching seasonal influenza.

While seasonal influenza viruses

are detected year-round,

flu viruses peak during the autumn and winter.

It is actually surprisingly unknown

why we have seasonal peaks of influenza.

There are a number of thoughts,

but none of them are completely clear.

One reason appears to be that

the drier and colder conditions make the virus more stable.

Another probably very important factor is that in winter,

we tend to huddle together much more.

And that means, for a virus that has infected one person,

it’s easier to get to the next one.

During an epidemic of seasonal influenza,

most of the terminal cases will be the elderly,

while those with severe complications

usually occur in people with a variety

of pre-existing medical conditions.

By contrast, a flu pandemic can kill younger,

otherwise healthy people,

and cause many more cases of viral pneumonia.

It seems when a completely new virus comes along,

and that’s the situation in a pandemic,

those who have the strongest immune response

may be the ones who suffer most.

And so that’s adolescents, young adults,

and those with the healthiest immune response.

The collateral damage may be what kills you

in that situation.

If you have a really strong immune system,

that gives you a really strong response.

Then your collateral damage may be really massive,

and that’s often what kills you.

In 2009,

the swine flu virus evolved

when a previously combined human-bird-swine virus

underwent a further mutation with a Eurasian pig virus

to form a new H1N1 super virus.

The 2009 swine flu was a classic case

of a very new virus hitting a population

that was immunologically not prepared for it.

So there was no protection

from the viruses that had been around before.

The outbreak first surfaced as an epidemic

in the state of Veracruz, Mexico,

where a 5-year-old boy became ill

with a high fever and typical flu-like symptoms.

It was discovered that he had been infected

with a new kind of variant influenza virus

previously seen only among swine populations.

The boy went down in history as boy zero,

the first person to kick-start the swine flu pandemic.

He was lucky to survive,

though the same cannot be said

for the countless other swine flu victims.

I’m just really scared

because I don’t know, um, if little kids are getting sick

or if there’s a certain medicine for little kids.

In March 2009,

I got a call from my friend and colleague Nancy Cox,

who directs the influenza division

of U.S. Centers for Disease Control in Atlanta,

saying that they had just got

some test results back from California

which indicated that two children who’d been to Mexico

were infected with a previously unknown flu virus.

That became public knowledge,

I think, two or three days later.

We were already gearing up to assist in London,

our colleagues in the United States,

the World Health Organization in London.

And we now know the virus had probably been circulating,

at that point, probably for five or six months,

without really being detected.

But of course, initially,

what people saw were the really quite sick people.

They saw the tip of the iceberg.

People in hospitals in Mexico, and in the United States,

and there was real concern.

We started seeing cases appearing, being detected,

really, across the world in 20, 30 countries within six weeks

of the initial announcement.

And the virus spread very fast.

The first confirmed death from the swine flu virus

occurred at the Texas Children’s Hospital in Houston.

It was a toddler from Mexico City,

who had been visiting family in Brownsville, Texas

before being air-lifted to Houston for treatment.

The World Health Organization’s

Strategic Health Operations Center,

known as the SHOC room, was activated.

For the next few months,

the SHOC room would become the center

of a worldwide battle

against the H1N1 swine flu virus.

On the 24th of April,

the Center for Disease Control

uploaded the complete gene sequences

of the 2009 H1N1 virus to a public influenza database.

Scientists around the world

could now use the sequences

and compare them to samples from their own countries,

in order to more rapidly determine

the spread of the virus.

On Saturday, the 25th of April 2009,

the Director General of the World Health Organization

declared the outbreak a public health emergency

of international concern,

admitting that the swine flu epidemic

could not be successfully contained.

Most cases of severe and fatal infections have been in adults,

in adults between the ages of 30 and 50 years.

This pattern is significantly different

from that seen during epidemics of seasonal influenza.

The pandemic alert level was raised to Phase 4,

indicating that the virus

was spreading abundantly between humans.

On the same day, officials in New York City

reported that they were investigating

a cluster of influenza-like illness in a local high school.

The Center for Disease Control

next confirmed two infections in Kansas,

and another case in Ohio.

In the midst of a bourgeoning public health emergency,

the U.S. began releasing a stockpile of supplies

which could be used to protect and treat the public,

including over 39 million masks and respirators,

gowns, gloves and face shields,

as well as 11 million doses of antiviral drugs.

On the 28th of April,

it was suspected that the virus had further spread to Germany,

with seven more cases being reported from that country.

The following day, the World Health Organization

raised its pandemic alert to Phase 5,

signaling to the global community

that a pandemic was now imminent.

As panic about the virus spread,

draconian measures began to take force around the world.

Egypt began a cull of all domestic pigs in the country.

In Germany’s western state of Saarland,

kissing was banned as a form of personal greeting.

Eventually, more than 70 countries

were reporting cases of infection.

The W.H.O. were forced to raise the threat level to Phase 6,

the highest categorization on the pandemic alert chart.

I have, therefore, decided to raise the level

of influenza pandemic alert from Phase 5

to Phase 6.

The world is now at the start

of the 2009 influenza pandemic.

The world was now facing a global influenza pandemic

for the first time in 41 years.

Throughout June and July,

Europe was experiencing a steep rise in new cases,

with a whopping 11,159 people infected in Britain alone.

Germany followed in second place,

with 2455 confirmed cases.

Throughout the world, immunization was seen

as the only effective means

of stopping the spread of the disease.

However, the new H1N1 vaccine was in short supply.

In America, the CDC recommended

that initial doses be administered to priority groups

such as pregnant women,

people who lived with or cared for babies,

children 6 months to 4 years old,

and health-care workers.

In the U.K., the NHS recommended

that vaccine priority go to people over 6 months old

who were clinically at risk for seasonal flu, pregnant women,

or households of people with compromised immunity.

It was initially proposed that two doses would be required,

but clinical trials demonstrated

that adults were receiving sufficient protection

after only a single injection.

But unfortunately, the vaccine was still

in the process of development,

and would not be ready for use before the end of September.

By that time,

the first official death on German soil was announced.

The country would see further losses of life

throughout October, including the deaths

of a previously healthy 5-year-old boy

and a 48-year-old mother of four.

By November,

a total of 53,968 German nationals

had confirmed infections.

Thirteen people had died as a result.

I think we were lucky in the 2009 pandemic.

The virus wasn’t very pathogenic,

because the rate by which it spread was amazing.

And, um, had it been a virus strain

that gave much more severe flu than the seasonal strains,

then we would have been in deep trouble.

And this was not predictable, that was, if you want,

that was sheer luck.

But despite these tragic figures,

the overall worldwide deaths

from the 2009 to 2010 swine flu outbreak

were fewer than in previous influenza pandemics.

Research shows that as many as 579,000 people

could have perished from the disease,

with figures suggesting

that a disproportionate number of deaths

likely occurred in Southeast Asia and Africa,

where access to prevention and treatment resources

is more limited.

The total number of people infected

was probably about a third of the world’s population

in the first 12 months or so,

but only a minority of those

would have showed any symptoms at all.

Probably only about 10 to 15 percent

of the global population showed symptoms.

Then there were later waves of transmission,

which infected more people

and now, at this point, probably most of them,

90 percent of the world’s population,

have been infected with that virus,

or its descendants.

For the most part,

it seemed that the world had been largely spared

from the major horrors some had predicted.

But it wasn’t long before another highly contagious

and deadly viral disease

threatened to overwhelm the world.

That disease was known as Ebola.

The outbreak of Ebola between 2014 and 2016

was the largest and most complex epidemic of the virus

since it was first discovered in 1976.

It killed a staggering five times more people

than all other known Ebola outbreaks combined.

The outbreak began in Guinea,

before moving across land borders

to Sierra Leone and Liberia,

and eventually found its way to Europe and North America.

There is an incubation period for Ebola

of anywhere from two to 21 days

before the victim will begin displaying

visible symptoms of the disease.

For this reason, the World Health Organization

will only declare the conclusion of an outbreak

once 42 days have elapsed,

the equivalent of two incubation periods

with no new infections being reported.

On average,

roughly half of patients who catch the disease will die.

Historically, there have been outbreaks

where the mortality rate was as high as 90 percent.

It’s a horrible infection to have, frankly.

It causes a widely disseminated infection.

The virus is in almost every body tissue.

Early initial symptoms are mostly gastrointestinal:

profuse diarrhea, vomiting,

with very high-end levels of virus shared.

It can also then cause a hemorrhagic fever,

where you bleed from eyes and other orifices.

It’s got a very high fatality rate.

We think about 60 to 70 percent,

typically, of people die,

usually from multiple organ failure.

It’s one of the most lethal viruses we know.

It spreads from person to person through bodily fluids.

Typically, people caring for a sick relative will get infected

because the fluids are very highly infectious.

Early medical care,

combined with rehydration and drugs to relieve the symptoms,

can decidedly improve one’s chances of survival.

But as yet, there is no licensed treatment

proven to neutralize the virus,

although a range of blood, immunological

and drug therapies are currently being developed.

The Ebola virus will be spread between humans

either through the blood or bodily fluids

of an infected person.

Breast milk, saliva, semen, feces

and tears are all highly infectious.

Studies have shown that traces of Ebola

may even remain in a man’s semen

for more than a year

after he has recovered from the disease.

The virus can also survive

for several days outside of the body,

so cleaning up body fluids or touching the soiled clothing

of an infected person can also lead to infection.

According to the W.H.O.,

health care workers are between 21 and 32 times more likely

to be infected with Ebola

than people in the general adult population.

They must wear a face shield,

or a medical mask and goggles,

if they are to be within one meter of a patient.

It is also necessary that workers wear

a long-sleeved gown and gloves.

Fifteen of our health workers

from this case management center have passed away.

When somebody dies of Ebola,

that time the virus is very virulent.

And in that case, we have to handle that corpse very well,

in order not for us to be infected.

Ebola infections are so deadly

because the virus infects the cells

that line your blood vessels

and this leads to massive leakage,

and essentially inner bleeding.

So it’s a very, very virulent virus

that kills you just quite rapidly.

Ebola virus is a virus

that is not constantly present in the population.

So that means there is no immunity in the population

due to having seen the virus before.

If the virus manages to be transmitted

from a patient or a victim to a new person,

then it can just very explosively expand

in the new person, and, um, be deadly.

The standard methods of treatment for Ebola patients

have remained the same for many years.

It consists of oral or intravenous rehydration

and electrolyte replacement,

coupled with drugs to decrease vomiting and diarrhea,

as well as to mitigate the symptoms of pain and fever.

Patients who are also at risk of contracting malaria

are given anti-malarial medication and antibiotics

so they don’t have to fight both diseases at once.

There are drugs being developed to treat Ebola

that stop the virus from replicating.

Another treatment being studied is the use of immunotherapy

by giving transfusions of blood from survivors.

Further potential treatment

could be the mechanical filtering of patients’ blood.

All the infections occurring in the West African Ebola epidemic

in 2014 and 2015

can be traced back to an 18-month-old boy

from the village of Meliandou, in the southern part of Guinea.

According to the American Center

for Disease Control and Prevention,

the boy is believed to have been infected by a bat.

He died on the 28th of December 2013,

followed throughout the next month by his mother,

sister and eventually, his grandmother.

On the 1st of February 2014,

a member of the deceased child’s extended family

traveled to Conakry, the capital of Guinea.

That individual died four days later,

having by then infected many other people.

The World Health Organization

opened an investigation on the 13th of March

after the Guinea Ministry of Health issued an alert

about the unidentified infections,

which they suspected was Lassa fever,

very common to the region.

Samples of the pathogen

were immediately sent to the Pasteur Institute in France.

Within a day, they confirmed that the patients

from which samples had been taken

were infected not by Lassa fever

but by Ebola.

The W.H.O. officially announced

that there was an outbreak of Ebola.

At that stage, there were already 49 confirmed cases

and 29 deaths.

It’s just amazing how this disease

can spread so widely and so silently

and then have such devastating effects in the community.

So it is very important

to not give false hope to anybody

that Ebola can be treated now.

This is absolutely not the case.

What we are relying on now

is proper implementation

of infection prevention and control,

control tracing and quarantine of people who have the disease,

quarantining of contact to make sure

that they would be under proper treatment

if they, indeed, have the disease.

Between early June and the middle of September,

the epidemic grew exponentially.

National case numbers were doubling every 16 to 30 days.

The United Nations Security Council issued a statement

stating that they were extremely concerned

about the Ebola epidemic.

They sought immediate help

from the international community

to stop any further spread of the virus.

On the 23rd of July,

the World Health Organization confirmed

that there were now more than 800 Ebola cases in the region.

The Peace Corps took the painful decision

to evacuate its volunteers from Liberia,

Sierra Leone and Guinea,

because of concerns for their health and safety.

The Center for Disease Control in America

warned U.S. residents to avoid all non-essential travel

to those countries.

By the middle of September,

there were 5000 reported cases of Ebola

and almost 2500 deaths across the globe.

At the special request of the World Health Organization,

Germany began admitting patients into the country

who required immediate treatment.

German doctors admitted a foreign patient

into a brand-new tropical medicine unit in Hamburg,

which specialized in the treatment

of contagious diseases.

Staff members of the facility assured the press

that the critically ill patient

posed no significant risk of spreading infection.

He would be treated in a special isolation ward

behind three separate air locks.

Within the isolation unit, no liquids, gases,

or particles in the air

could possibly reach the outside world.

This extraordinary safety measure was put in place,

despite how unlikely it is for Ebola

to spread through the air.

The W.H.O. said that the patient worked

in an Ebola testing laboratory in Sierra Leone.

He arrived at Hamburg airport

on the 27th of August in a specialized plane,

which had been modified to transport patients

requiring isolation.

From there, he was transferred

to a special isolation ambulance,

accompanied by a convoy of police cars on its journey

to the University Hospital Hamburg-Eppendorf.

When news of the patient’s arrival

was released to the public,

reactions were mixed.

Some expressed concern

that allowing such a contagious person into the city

could pose a genuine public health risk.

Others felt that the need to help this desperate person

far outweighed any potential for danger.

They also contended that the treatment

could aid and advance medical research.

On the 3rd of October,

Germany accepted yet another Ebola victim,

this time to a hospital in Frankfurt-am-Main.

They were flown in on a medical flight from West Africa

and transferred to the isolation unit

at Frankfurt University Hospital,

all under deep cover.

The patient was a Ugandan doctor

who had been working with Ebola patients in Sierra Leone

before falling ill with the virus himself.

Though two of his patients

responded positively to treatment,

both he and a third patient had not been so lucky.

This third patient had been a U.N. employee from Liberia

who landed in the northern German town of Leipzig,

200 kilometers southeast of Berlin,

in the early hours of the morning.

There, they were met by a medical team

wearing biohazard suits

and taken immediately to St. George hospital in Leipzig,

which had a tropical disease clinic with six rooms

where the patient could be treated

under the strictest quarantine.

Sadly, despite their best efforts,

the patient succumbed to the disease.

The first individual to die of Ebola on German soil.

On the 24th of November,

it was also confirmed

that an Italian doctor who had been working

for a medical charity treating Ebola victims in Sierra Leone

had, himself, become infected with the disease.

He was flown back to Rome

where he was successfully treated.

On the 29th of December 2014,

the United Kingdom was also drawn into the epidemic

when the first case of Ebola was confirmed in the nation.

The victim was a female nurse

who had returned from voluntary work

at an Ebola treatment center in Sierra Leone.

This case was concerning,

because her journey from Freetown

had taken her to several major global cities.

First, to Casablanca in Morocco.

Next to London, in England.

And finally, to Glasgow, in Scotland,

her ultimate destination.

After suffering from fever and headache,

she was admitted to a specialist unit

for infectious diseases

at the Gartnavel Hospital in Glasgow,

where she was kept in strict isolation.

The patient was displaying no symptoms of the kind

that would lead to onward transmission

and put other people at risk

before she had reported, this morning, as being unwell.

A day later, she was transferred

for specialist treatment at the Royal Free hospital,

where the facilities, staff and systems

were in place to ensure the safest care.

Public health authorities

began to investigate possible contacts

that the nurse may have had with other people in Britain.

It’s important to stress

that the risk to the general public remains very low,

but we are contacting the passengers

who were on the flight with her.

There’s a special dedicated help line for them to call,

so that if they have any concerns at all,

they’re able to communicate easily.

As well as liaising

with the World Health Authority in Morocco,

where the victim had changed flights

on her journey back to the U.K.

She has since made a full recovery.

As of April 2015,

there were 176 organizations in Sierra Leone,

Guinea and Liberia,

all conducting emergency programs.

Liberia was initially declared Ebola-free

by the World Health Organization

on the 9th of May 2015,

after more than 4000 people had died.

But Ebola was not yet beaten.

On the 12th of May 2015,

an Italian healthcare worker

who had been treating Ebola patients

in Sierra Leone for nearly three months,

fell ill three days after returning back to Italy.

He was taken to the infectious diseases ward

at the hospital of Sassari in Sardinia,

where he tested positive for Ebola.

Several small outbreaks reoccurred in Liberia,

with a cluster of six new cases confirmed in June 2015.

On the 3rd of September 2015,

Liberia was again declared Ebola-free

before the emergence of an additional three cases.

I came on the beach today to celebrate Ebola

because Ebola has left Liberia,

and we are going back to our normal activities.

I just came on the beach to enjoy myself because I’m alive.

Ebola did not take my life,

and none of my family alive were taken away by Ebola.

So I came on the beach today to enjoy myself.

Guinea was declared Ebola-free

on the 29th of December,

with Liberia to follow on the 14th of January 2016.

This was now its third official declaration

of complete inoculation,

only this time, things stayed that way.

People should not remain complacent.

It was the same complacence

that led to the second round of the virus emergence.

And people should continue to observe the practices

to ensure that they can remain safe.

Once Sierra Leone was given the all clear,

all three West African countries

had officially become Ebola-free.

The World Health Organization

lifted the Public Health Emergency

of International Concern related to the epidemic.

The W.H.O. reported that there had been around 28,000 cases,

with more than 11,000 deaths due to the epidemic.

But the true human cost of Ebola was much higher.

It has been estimated that over than 30,000 children

were left orphaned by the disease.

According to Médecins Sans Frontiers,

also known as Doctors Without Borders,

it is impossible to be sure how many people died

as a result of the Ebola epidemic.

In addition to those deaths

resulting directly from the Ebola virus,

there followed a dramatic increase

in latter mortality rates,

due to an increasing lack of basic health care.

This can be demonstrated by the fact that as of March 2015,

over a million fewer children were vaccinated against measles

than prior to when the epidemic began,

which undoubtedly led to more deaths from that disease.

There was also an increase in the number of people

who lacked food security

as a result of the 2014 Ebola epidemic.

This was estimated to be in the hundreds of thousands.

The health of pregnant women in West Africa

was also drastically impacted by the Ebola epidemic.

Pregnancy appeared to make women more vulnerable

to the effects of the Ebola infection.

It particularly increased their risk of hemorrhage.

There was also evidence suggesting that the virus

was able to cross from the placenta

into both the amniotic fluid and the developing fetus.

Tragically, the pregnancies of women infected with Ebola

all ended through either a spontaneous miscarriage,

stillbirth, or death of the newborn baby within a few days.

On top of the dangers Ebola presented to the mother,

healthcare workers assisting the delivery of babies

were at extreme risk of infection.

The fear of health workers treating women

from areas known to be high in Ebola cases

led to a lack of maternal care for pregnant women.

The United Nations Population Fund

estimated that the Ebola epidemic

could have either directly or indirectly

resulted in as many as 120,000 maternal deaths

by the end of October 2015.

The psychological well-being of the survivors of Ebola,

as well as the families of patients

and victims of the disease became a major concern.

I’ve met some people who have had Ebola,

and they described it in first-person terms to me.

And it’s not--

You wouldn’t wish it on your worst enemy.

In July 2014,

the first case of Ebola was diagnosed outside of Africa.

This meant that the outbreak could no longer just be viewed

as a humanitarian crisis.

It had become a palpable security threat

to countries all across the globe.

Due to the rapid interconnectedness

of the modern world,

leaders could no longer ignore

urgent health crises in distant countries,

as they would be putting their own citizens

at a greater risk of infection.

The lessons we learn,

particularly from the Ebola epidemic in 2014/15,

which affected some of the poorest countries in the world,

was that if we don’t improve

the ability of the poorest countries to respond now,

we’re going to be left, as the wealthy countries,

having to intervene later, and spending a lot more money,

a lot more people dying, a lot more risk to ourselves,

than we would if we had invested to start with,

and helped those countries develop the capacity they need.

As a result of this epidemic,

several influential figures

have called for a renewed focus

on international public health issues.

Microsoft founder Bill Gates has spent billions of dollars

working towards the eradication of global diseases.

He has advocated for building health organizations in most,

if not all, countries around the globe,

which could function

as an international early alert system

for potential new outbreaks.

Some of those same kinds of preparations

of having lists of volunteers

and knowing that people are trained and really practicing

for something very challenging,

that’s probably one of the lessons

out of this Ebola epidemic.

A flu pandemic poses the biggest challenge,

in terms of responding quickly,

because flu spreads very, very fast.

It’s about two, three days

between one person getting infected

and them infecting the next person

and the next person.

So we know how to make flu vaccines against flu pandemics.

The challenge is that we’re in a race against time

against the virus itself.

So back in 2009, it took us about five, six months,

and we were doing well,

to make large amounts of the vaccine.

And that was already too late for much of the world.

There is enormous effort now, in the intervening 10 years,

to speeding up that process.

We’re not quite there yet,

but there is the potential of new technologies

allowing us to mass produce enormous quantities of vaccine

on a much faster timescale.

And I would envisage that in the next 10 years,

those-- Those new technologies will come to fruition.

The 2014 Ebola epidemic in West Africa

highlighted major deficiencies

in the ability of the international public health

and scientific communities

to respond to infectious disease emergencies.

It also provided a stark reminder of the consequences

of not investing in the development

of healthcare infrastructure in developing countries.

The world kind of woke up to the threat of new epidemics,

really, with the SARS epidemic in 2003/4,

followed by avian influenza.

The wealthy countries in the world

then started investing significantly,

both in research, but also in preparedness.

And that is...

First of all, in health systems, better surveillance.

Picking up diseases at the earliest possible stage

in an epidemic, so you have time to do something about it.

Improving our ability to make vaccines,

for instance, against flu viruses.

Also, now, just in the last few years,

starting to actually develop vaccines

against some of these viruses,

even before they become a pandemic.

And then there’s, of course,

much of the world is not wealthy enough

to put enormous amounts of money

into epidemic preparedness.

But even there, there has been the increasing investment,

by particularly, like the U.K., Germany, the United States,

in helping countries develop healthcare infrastructure,

which enhances surveillance, more generally,

enhances their ability to respond

to that sort of emergency.

There is, however,

still an issue.

Companies are focusing

on the development of drugs and vaccines

to tackle the chronic diseases

which predominately affect people in the developed world,

and not the diseases which are more likely to cause epidemics.

If we are going to prevent future pandemics,

we must be continually developing

powerful new vaccines.

When it comes to flu, one of the things that’s interesting

and quite stunning are the recent efforts

to develop a vaccine that does not require prediction anymore.

These are called "pan-influenza" vaccines.

The idea is you find a way to vaccinate people

against any flu strain that is out there.

I think, we are relatively far away from this,

but if that worked, of course, that would be amazing.

Certainly, it’s true,

that we have an ever-present risk of a lethal pandemic.

And if we’re talking about, for instance,

a virus similar in lethality to the 1918 pandemic,

even with modern medical technologies,

that could easily cause 30 million deaths worldwide.

We must also do our best to address changes

that are occurring in the Earth’s climate,

which can affect the spread

and reach of infectious diseases.

We know from malaria, for instance,

the limits of malaria infection in the world

are dictated by the mosquitoes that can transmit it.

The limit there is that they have to survive the winter

so that the parasites can develop in the mosquitoes

and then come back next year.

Now, with global warming,

these mosquitoes can extend much more to the north

than they did in the past.

There are similar developments for viruses

that use mosquitoes to transmit.

One example is the West Nile virus in the U.S.,

which didn’t exist there,

but now is there because it can be transmitted by mosquitoes

that didn’t live there before.

So global warming

clearly plays into the distribution

of infectious diseases.

The Ebola outbreak clearly demonstrated the risk

that increasing accessibility to air travel

can pose to infection control.

As well as the spread of disease,

there is also the panic that can ensue

when infected people are moving freely and quickly

across international borders.

It is clear that within an ever more interconnected world,

the threat of diseases

spreading rapidly around the globe

has become more probable than ever.

And if a global pandemic does, indeed, become our reality,

it won’t matter who you are, or what continent you live on.

No one on this planet will be truly safe

if Mother Nature unleashes

her most inescapable deadly disaster.