on average, they would spread it to two or three other people.

平均來說，他們會把它傳播給其他兩三個人。

Those two or three other people would, on average, spread it to another two or three.

這兩三個人，平均下來，又會分散到另外兩三個人身上。

And so on, and so on.

等等，等等。

One out of every 200 people who became infected died.

每200名感染者中就有一人死亡。

In one year, this virus killed over two million people worldwide.

一年內，這種病毒在全球範圍內造成了200多萬人的死亡。

Now let's back up:

現在讓我們退後。

Imagine if the virus were even more contagious –

想象一下，如果病毒的傳染性更強------。

if every infected person passed it on to an average of four, or six people;

如果每個感染者平均傳給四個人，或者六個人。

and if its fatality rate was much, much higher:

而如果其死亡率要高很多很多。

closer to three in ten.

接近十分之三。

This devastating scenario is smallpox.

這種毀滅性的場景就是天花。

Smallpox claimed hundreds of millions of lives in the 20th century alone,

僅在20世紀，天花就奪去了數億人的生命。

and plagued humanity for centuries before that.

並在這之前的幾個世紀裡一直困擾著人類。

And then it was gone.

然後就不見了。

We completely wiped it out of existence.

我們把它徹底消滅了。

So, how did we do it?

那麼，我們是怎麼做的呢？

And can we do it again?

我們還能再做一次嗎？

It starts with a vaccine.

這要從疫苗說起。

In the late 1700s, a scientist named Edward Jenner

17世紀末，一位名叫愛德華-詹納的科學家。

developed a brand new way to fight smallpox.

開發了一種全新的抗擊天花的方法。

He called it “vaccination.”

他稱之為 "疫苗接種"。

Before this point, the only way to gain immunity from smallpox was to catch it:

在這之前，獲得天花免疫力的唯一途徑就是感染天花。

either through misfortune, or on purpose.

或因禍得福，或有意為之。

Jenner's method was far less dangerous.

詹納的方法遠沒有那麼危險。

Word of the vaccine spread quickly.

疫苗的消息很快就傳開了。

Within five years it was in the Americas.

五年之內，它就在美洲。

Within ten, it was brought to Asia.

十內，就被帶到了亞洲。

Vaccination alone would eventually be enough to drastically reduce cases.

單單接種疫苗最終就足以大幅減少病例。

And that's partially because of how smallpox is spread.

而這部分是因為天花的傳播方式。

Unlike a disease like malaria, which can spread to humans from mosquitoes;

不像瘧疾這種疾病，可以通過蚊子傳播給人類。

or Ebola, which can spread to humans from bats and other animals;

或埃博拉病毒，它可以從蝙蝠和其他動物傳播給人類。

smallpox could only be spread to humans from other humans.

天花只能由其他人類傳播給人類。

There were no animal vectors.

沒有動物媒介。

Which means vaccinating people would slowly eliminate the only way it could spread.

也就是說給人打疫苗會慢慢消除它唯一的傳播途徑。

By the early 1900s, most of Europe, the United States, and Canada

到了20世紀初，歐洲、美國和加拿大的大部分國家

had nearly wiped out smallpox.

幾乎消滅了天花。

But countries with fewer resources, civil unrest, or higher population density

但資源較少、內亂或人口密度較高的國家。

struggled to effectively vaccinate and contain the virus.

難以有效地接種疫苗和控制病毒。

And as long as smallpox existed somewhere,

而只要有天花存在的地方。

it was a threat to people everywhere.

這對各地的人都是一種威脅。

True eradication would require a global effort.

真正的根除需要全球的努力。

"Within the framework of the United Nations, a new organization exists

"在聯合國的框架內，存在一個新的組織，即：

to promote the welfare of all people:

促進全體人民的福利；

the World Health Organization."

世界衛生組織"。

In 1967, the World Health Organization established a unified plan

1967年，世界衛生組織制定了一個統一的計劃。

to eradicate smallpox once and for all.

一勞永逸地消滅天花。

Having a centralized agency changed the game for public health.

有了一個集中的機構，改變了公共衛生的遊戲規則。

Nations pulled together, and vaccination campaigns spread around the globe.

各國齊心協力，疫苗接種運動遍及全球。

Initially, the goal was simple: vaccinate everyone.

最初的目標很簡單：給所有人接種疫苗。

But that proved harder in densely populated places like India,

但事實證明，在印度這樣的人口稠密的地方，這更難。

where it was hard to track outbreaks and the virus could spread quickly.

在那裡，很難追蹤疫情的爆發，病毒也會迅速傳播。

In 1974, over 15,000 people in India died of smallpox in the span of five months.

1974年，印度有15000多人在5個月內死於天花。

So the World Health Organization proposed a more targeted approach:

所以世界衛生組織提出了一個更有針對性的方法。

Instead of trying to vaccinate everyone at once,

而不是想一下子給所有人接種疫苗。

public health officials focused on infected individuals,

公共衛生官員重點關注感染者。

using a form of contact tracing.

使用一種接觸追蹤的形式。

Doctors and volunteers would isolate the person

醫生和志願者會把這個人隔離起來

and vaccinate anyone who had come into contact with them --

併為所有接觸過他們的人接種疫苗 -- -- 疫苗是一種特殊的工具。

and then, whoever had come into contact with those people,

然後，凡是和這些人接觸過的人。

effectively creating a buffer of immunity between the infection and the rest of society.

有效地在感染者和社會其他人之間建立了免疫力的緩衝區。

This was called “ring vaccination.”

這就是所謂的 "環狀疫苗"。

It worked. Really well. Not just in India, but around the world.

它的工作。真的很好。不只是在印度，而是在全世界。

And on May 8th, 1980, the World Health Organization declared smallpox eradicated.

而在1980年5月8日，世界衛生組織宣佈消滅天花。

These are the four factors that helped us eradicate smallpox.

這就是幫助我們消滅天花的四個因素。

And while there's no single path to disease eradication,

雖然消滅疾病的途徑並不單一。

if one or more of these can't be met, it will make it much harder, if not impossible.

如果不能滿足其中的一個或多個條件，就會增加難度，如果不是不可能。

So let's talk about Covid-19.

所以我們來談談科維德-19。

Vaccines aren't the problem.

疫苗不是問題所在。

New technologies have brought us effective and safe vaccines in record time.

新技術為我們帶來了有效和安全的疫苗，時間創下了新紀錄。

The issue with Covid-19 is the way it spreads.

科維德-19的問題在於它的傳播方式。

Let's start with animal vectors.

先說說動物載體吧。

Researchers believe the SARS_CoV2 virus originated in bats,

研究人員認為SARS_CoV2病毒起源於蝙蝠。

which means there's a way for it to spread from animals to humans.

這意味著它有辦法從動物傳播到人類。

So, even if we were to completely remove it from the human population,

所以，即使我們要把它從人類中完全清除。

it could reappear, just as it did the first time.

它可以重新出現，就像第一次一樣。

But the way it spreads from human to human is also a problem.

但它在人與人之間的傳播方式也是一個問題。

A person with smallpox could only spread the disease if they were showing symptoms.

得了天花的人只有在出現症狀的情況下才能傳播疾病。

But a person with Covid-19 can be contagious days before that point.

但科維德-19患者在這之前幾天就可以傳染。

Some people never develop symptoms at all.

有些人根本就沒有出現症狀。

It's much harder to effectively trace something you can't see,

要想有效地追蹤你看不到的東西，難度更大。

or isolate a person who doesn't even realize that they're sick.

或隔離一個甚至不知道自己生病的人。

And then there's this.

然後是這個。

From the beginning of the pandemic, many countries have taken a nationalist approach to it.

從疫情發生之初，許多國家就採取了民族主義的態度。

Some countries banned exports of protective gear,

一些國家禁止出口防護裝備。

some countries restricted the export of vital drugs,

一些國家限制重要藥品的出口。

and the United States pulled funding from the World Health Organization.

和美國從世界衛生組織撤回資金。

In a September meeting, the UN secretary General said,

在9月的一次會議上，聯合國祕書長說：

“The pandemic is a clear test of international cooperation –

"這種大流行病是對國際合作的一個明顯考驗----

a test we have essentially failed.”

我們基本上沒有通過測試。"

Even as vaccines became available, richer countries are buying up the supply,

即使在疫苗上市後，較富裕的國家也在購買供應。

leaving poorer nations behind.

把較窮的國家甩在後面。

And that's a big problem,

而這是一個大問題。

because leaving the virus to spread unchecked in these other places

因為任由病毒在這些其他地方肆意傳播。

gives it more time to spread,

讓它有更多的時間去傳播。

which increases the chance it will mutate.

這增加了它變異的機會。

Variants of the virus are already popping up,

該病毒的變種已經出現了。

and that leaves the whole world at risk.

這讓整個世界都處於危險之中。

All in all, Covid-19 is just not a good candidate for eradication.

總而言之，科維德-19就是不適合剷除。

But eradication isn't the only option.

但剷除並不是唯一的選擇。

Smallpox is the only human disease we've ever eradicated.

天花是我們唯一消滅過的人類疾病。

It's much more common for us to contain and control a disease.

對於我們來說，控制和控制疾病更為常見。

And that's where many researchers think we'll land with Covid-19:

而這也是許多研究人員認為我們會在Covid-19上落地的地方。

we'll vaccinate, and manage.

我們會接種疫苗，並管理。

Lockdowns and quarantines will end,

封鎖和隔離將結束。

and we might end up with a virus that we manage with an annual vaccine,

我們最終可能會用每年的疫苗來控制病毒。

like the flu.

像感冒一樣。

Or, something even more mild:

或者，更溫和的東西。

As more adults and vulnerable populations build immunity,

隨著越來越多的成年人和弱勢人群建立起免疫力。

it's possible Covid-19 will become "endemic":

Covid-19有可能成為 "地方病"。

always around, but rarely developing into anything more than a common cold.

總是在身邊，但很少發展成比普通感冒更嚴重的事情。

It's not the best answer.

這不是最好的答案。

But it's a reality we'll learn to be comfortable with.

但這是我們要學會適應的現實。

We'll be able to go back to the way things were before.

我們就可以回到以前的狀態了。

But we shouldn't.

但我們不應該。

Eradicating smallpox took a colossal effort:

根除天花需要付出巨大的努力。

centuries to create effective vaccines,

幾個世紀來創造有效的疫苗。

and then decades more to build the framework needed for global campaigns.

然後再過幾十年建立全球運動所需的框架。

It's a reminder of what we're capable of as a society.

這提醒了我們作為一個社會的能力。

But it's also a warning:

但這也是一種警告。

Covid-19 is far from the worst disease nature has to offer.

科維德-19遠不是大自然所能提供的最糟糕的疾病。

And this pandemic has shown us that we're not ready for something worse.

而這次的大流行讓我們看到，我們還沒有準備好迎接更糟糕的事情。

Because our failure isn't that we can't eradicate Covid-19;

因為我們的失敗不是因為我們不能根除Covid-19。

it's that we let it rise to pandemic proportions to begin with.

是我們讓它上升到大流行的比例開始。