时代周刊:新冠疫情结束的条件(1)（在线收听）

How does a pandemic end?

大流行如何结束？

The 1918 flu offers a hint

1918年的流感给了我们一个提示

By Olivia B. Waxman

文/奥利维亚·B·瓦克斯曼

More than six months after the World Health Organization declared COVID-19 a pandemic,

世卫组织宣布新冠肺炎为大流行的六个多月后，

one question remains decidedly unanswered: How will it come to an end?

有一个问题仍然没有明确的答案：这次的大流行会怎样结束？

It seems safe to say that someday, somehow, it will end.

我们似乎可以肯定地说，这场大流行的结束只是迟早的问题，方式的问题。

After all, other viral pandemics have.

毕竟，其他病毒大流行就是如此。

Take, for example, the flu pandemic of 1918–19.

我们就以1918~1919年的流感大流行为例。

That earlier pandemic was the deadliest in the 20th century;

那场大流行是20世纪最致命的一次大流行；

it infected about 500 million people and killed at least 50 million, including 675,000 in the U.S.

感染人数近5亿人，死亡人数至少5000万人，在美国就致死了67.5万人。

And while science has advanced significantly since then,

尽管自那以后科学发展已经取得了重大进步，

the uncertainty felt around the world today would have been familiar a century ago.

但全世界最近都陷入了不确定的感觉之中，放到一个世纪前，这种感觉也并不陌生。

In fact, even after that virus died out,

事实上，哪怕是在那场大流行结束之后，

it would be years before scientists better understood what had happened, and some mystery still remains.

科学家们也耗费了数年时间才有了更深刻的了解，才明白那场大流行究竟是怎么回事，尽管一些谜团至今仍未解开。

Here's what we do know: in order for a pandemic to end,

我们知道的是：一场大流行要结束，

the disease in question has to reach a point at which it is unable to successfully find enough hosts to catch it and then spread it.

有关疾病必须是已经发展到了无法成功找到足够多的宿主供其感染传播的阶段。

In the case of that pandemic, though it's famous for sweeping the world in 1918 and 1919, cases spiked again in early 1920.

就1918年那次大流行而言，尽管它在1918~1919年间因为席卷了全世界十分出名，1920年初再次出现了病例激增的情况。

As with other flu strains, it may have become more active in the winter because people were spending more time indoors in closer proximity to one another and because viruses can enter cracks in skin dried out by artificial heat and fires,

其他流感毒株一样，那次大流行的病毒之所以在冬天又变得活跃起来，一是因为冬天时人们在室内聚集的时间更久，二是在人工取暖器或火堆的作用下人体皮肤会变得干燥，遭到了病毒的趁机入侵，

according to Howard Markel, physician and director of the Center for the History of Medicine at the University of Michigan.

密歇根大学医学史中心主任、内科医生霍华德·马克尔表示。

It wasn't until the middle of 1920 that the pandemic was finally over in many places,

那一次，很多地方的疫情一直持续到了1920年年中才结束，

though there was no official declaration that the coast was clear.

尽管到了那时，也没有官方宣布海岸已经安全。