How the COVID-19 vaccines were created so quickly - Kaitlyn Sadtler and Elizabeth Wayne

翻译人员: Helen Ji 校对人员: Yanyan Hong

In the 20th century, most vaccines took well over a decade

二十世纪时，多数疫苗 需要用至少十年时间

to research, test, and produce.

来完成科研、测试和生产。

But the vaccines for COVID-19 cleared the threshold for emergency use

但新型冠状病毒 (COVID-19) 的疫苗 在不到 11 个月内

in less than 11 months.

通过了紧急使用的临界点。

The secret behind this speed is a medical technology

这速度背后的秘密

是数十年医学技术发展的飞跃：

that’s been developing for decades:

the mRNA vaccine.

mRNA 疫苗。

This new treatment uses our body’s existing cellular machinery

这个新治疗方式 运用我们身体里现有的细胞机器

to trigger an immune response,

来触发免疫反应，

protecting us from viruses without ever experiencing an infection.

让我们不感染生病就能抵抗病毒。

And in the future, this approach might be able to treat new diseases

而在未来，这个方法或许 能以发现新疾病的同等速度

almost as quickly as they emerge.

找到治疗方法。

So how do these revolutionary vaccines work?

这个变革性的疫苗是如何运作的呢？

The key ingredient is in the name.

它的主要成分就在写在疫苗的名字里。

mRNA, or messenger ribonucleic acid, is a naturally occurring molecule

mRNA，或信使核糖核酸，

是个自然生成的 合成蛋白质的模板分子。

that encodes the instructions for producing proteins.

When our cells process mRNA, a part of the cell called the ribosome

当我们的细胞处理 mRNA 时，

一个叫核糖体的细胞部分

translates and follows these instructions to build the encoded protein.

将转译且复制对应的蛋白。

The mRNA in these vaccines works in exactly the same way,

这些疫苗里的 mRNA 使用相同的工作原理，

but scientists use the molecule to safely introduce our body to a virus.

但科学家们用这个分子 来安全地将病毒引入人体。

First, researchers encode trillions of mRNA molecules with the instructions

首先，科学家们 把特定的病毒蛋白质模版

for a specific viral protein.

编写到万亿个 mRNA 分子里。

This part of the virus is harmless by itself,

病毒的单独这一部分无害，

but helpful for training our body’s immune response.

但有助于训练体内的免疫反应。

Then, they inject those molecules into a nanoparticle

他们接下来将这些分子 注射到纳米药物里，

roughly 1,000 times smaller than the average cell.

大约比普通细胞小一千倍。

This nanoparticle is made of lipids,

这些纳米药物有间脂质构成，

the same type of fatty material that forms the membrane around our cells.

和我们细胞外包薄膜的 细胞间脂质为相同材质。

But these lipids have been specially engineered

但在这些间脂质受过特殊加工，

to protect the mRNA on its journey through the body

用来保护 mRNA， 让它完成在体内行程

and assist its entry into the cell.

且协助它进入细胞。

Lastly, the final ingredients are added: sugars and salt

到最后，加入剩下的成分：糖与盐，

to help keep the nanoparticles intact until they reach their destination.

用来保持纳米药物完好无缺， 直到它们地抵达目的地。

Before use, the vaccine is kept at a temperature of -20 to -80 degrees Celsius

在使用前，疫苗需保存在 零下 20 到 80 摄氏度的环境下，

to ensure none of the components break down.

以防其中任何成分的失效。

Once injected, the nanoparticles disperse and encounter cells.

一旦注射至体内，这些纳米粒子 会扩散并与细胞相遇。

The lipid coating on each nanoparticle fuses with the lipid membrane of a cell

每一个纳米粒子的间脂质 将与细胞间脂质结合

and releases the mRNA to do its work.

并通过释放 mRNA 来实现免疫。

At this point, we should note that while the vaccine is delivering

此刻值得一提： 虽然疫苗将病毒遗传物质

viral genetic material into our cells,

输送进我们身体里，

it’s impossible for this material to alter our DNA.

这个物质不可能更改我们的基因。

mRNA is a short-lived molecule

mRNA 分子寿命很短，

that would need additional enzymes and chemical signals to even access our DNA,

并需要其他的酶和化学信号 才能接触到我们的基因，

let alone change it.

更别提更改它了。

And none of these DNA altering components are present in mRNA vaccines.

mRNA 疫苗里也不包括 任何一个修改基因的部分。

Once inside the cell, the ribosome translates the mRNA’s instructions

一旦进入细胞，核糖体将转译 mRNA 的指令

and begins assembling the viral protein.

并开始组装病毒蛋白质。

In COVID-19 vaccines, that protein is one of the spikes typically found

新冠疫苗含有的蛋白是 病毒表面的刺突蛋白。

on the virus’s surface.

Without the rest of the virus this lone spike is not infectious,

少了剩下的病毒， 一个刺突蛋白没有感染力，

but it does trigger our immune response.

但是能触发我们的免疫反应。

Activating the immune system can be taxing on the body,

激活免疫系统会消耗体力，

resulting in brief fatigue, fever, and muscle soreness in some people.

给一些人带来短期疲劳、发烧， 和肌肉酸痛的反应。

But this doesn’t mean the recipient is sick—

但这不代表接种者生病了——

it means the vaccine is working.

代表着疫苗生效了。

The body is producing antibodies to fight that viral protein,

身体生产着抵抗病毒蛋白的抗体，

that will then stick around to defend against future COVID-19 infections.

能持续在身体里抵抗 未来的新冠感染。

And since this particular protein is likely to be found in most COVID variants,

由于这个蛋白很可能 在多种变异株上出现，

these antibodies should reduce the threat of catching new strains.

这些抗体应当减少 感染变异株的威胁性。

This approach offers significant advantages over previous vaccines.

这个手段比起原先的疫苗 有明显的优势。

Traditional vaccines contain weakened versions of live viruses

传统疫苗含有削弱的活病毒

or amputated sections of a virus,

或肢解病毒的一部分，

both of which required time intensive research to prepare

两个都需要耗时间的研究来生产

and unique chemical treatments to safely inject.

及特殊的化学处理方式 才能安全接种。

But mRNA vaccines don’t actually contain any viral particles,

可 mRNA 疫苗本身 不含有任何病毒颗粒，

so they don’t have to be built from scratch to safely adjust each virus.

所以为了安全加工每个病毒， 它们不需要每次都从零开始。

In fact, every mRNA vaccine could have roughly the same list of ingredients.

实际上，每支 mRNA 疫苗 都有相似的成分表。

Imagine a reliable, robustly tested vaccine that can treat any disease

想象一下，即可信又稳健的疫苗， 只需要更改一种成分

by swapping out a single component.

就能医治任何一种疾病。

To treat a new illness, researchers would identify the right viral protein,

治疗新兴疾病时，研究员们 要找到合适的病毒蛋白，

encode it into mRNA,

改写编辑到 mRNA 里，

and then swap that mRNA into the existing vaccine platform.

再把那个 mRNA 替换到 现有的疫苗载体内。

This could make it possible to develop new vaccines in weeks,

这样就使得数周内 研制出新的疫苗成为可能，

giving humanity a flexible new tool in the never-ending fight against disease.

为人类在与疾病的无止境战斗中 提供灵活的新方法。