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

譯者: Jo Ngan 審譯者: Helen Chang

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

在二十世紀，大多數疫苗

都需要遠超過十年的時間

to research, test, and produce.

來研發、測試和製造。

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

但新冠肺炎的疫苗僅在十一個月内

便成功衝關，獲批准緊急使用授權。

in less than 11 months.

The secret behind this speed is a medical technology

快速完成疫苗背後的秘密，

是一項已經發展數十年的醫療技術：

that’s been developing for decades:

the mRNA vaccine.

訊息 RNA（mRNA）疫苗。

This new treatment uses our body’s existing cellular machinery

這個新療法使用我們體内細胞 已有的物理結構和化學成分

to trigger an immune response,

來觸發免疫反應，

protecting us from viruses without ever experiencing an infection.

讓我們無需先受病毒感染 就能得到保護。

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

而在未來，這個方法有可能

almost as quickly as they emerge.

可以在新疾病甫出現時就將其根治。

So how do these revolutionary vaccines work?

那這些革命性的疫苗是如何運作的呢？

The key ingredient is in the name.

其實它的名稱已經包含了其關鍵成分：

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

mRNA，又稱訊息核糖核酸，

是一種自然產生的分子，

that encodes the instructions for producing proteins.

可以編碼指令，生產蛋白。

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

當我們的細胞處理 mRNA 時， 細胞内稱為核醣體的一部分

translates and follows these instructions to build the encoded protein.

會翻譯並按照這些指令來 構建編碼中寫的蛋白。

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

這些疫苗中的 mRNA 正是這樣運作，

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

但科學家會利用分子來安全地 把病毒引入我們的體内。

First, researchers encode trillions of mRNA molecules with the instructions

首先，研究人員把指定病毒蛋白的指令

for a specific viral protein.

編進數萬億的 mRNA 分子裏。

This part of the virus is harmless by itself,

病毒蛋白本身無害，

but helpful for training our body’s immune response.

但有助訓練我們身體的免疫反應。

Then, they inject those molecules into a nanoparticle

然後，他們將這些分子注入

roughly 1,000 times smaller than the average cell.

大約比普通細胞小一千倍的納米粒子。

This nanoparticle is made of lipids,

這種納米粒子由脂質構成，

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

與我們細胞膜的脂肪物質一樣。

But these lipids have been specially engineered

但這些脂質亦經過特別設計

to protect the mRNA on its journey through the body

來在一路上保護 mRNA，

and assist its entry into the cell.

協助它進入細胞。

Lastly, the final ingredients are added: sugars and salt

最後，添加最終成分：

糖和鹽用來幫助納米粒子 在到達目的地前維持完整。

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

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

使用前，疫苗保存在 -20 至 -80 攝氏度的溫度，

to ensure none of the components break down.

以確保沒有任何成分分解。

Once injected, the nanoparticles disperse and encounter cells.

一經注射，納米粒子便會分散並接觸細胞，

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

每粒納米顆粒上的脂質層 與細胞的脂質膜融合，

and releases the mRNA to do its work.

繼而釋放 mRNA 來讓它開始其工作。

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

在這個時候，我們應要留意的，

是雖然疫苗將病毒遺傳物質 輸送到我們的細胞中，

viral genetic material into our cells,

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

但這物質不會有可能 改變到我們的 DNA。

mRNA is a short-lived molecule

mRNA 是一種壽命短暫的分子，

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

需要額外的酵素和化學訊號才能 存取我們的 DNA，

let alone change it.

更不用說改變它了。

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

再者，這些能改變 DNA 的成分 都不存在於 mRNA 疫苗中。

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

一旦進入細胞， 核醣體就會翻譯 mRNA 的指令

and begins assembling the viral protein.

並開始組裝病毒蛋白。

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

在新冠肺炎的疫苗中，這種蛋白

就是通常在病毒表面發現的尖刺之一。

on the virus’s surface.

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

沒有病毒的其餘部分， 這單一尖刺沒有傳染力，

but it does trigger our immune response.

但卻會觸發我們的免疫反應。

Activating the immune system can be taxing on the body,

免疫系統激活後會對身體造成負擔，

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

在一些人身上會出現 短暫的疲勞、發燒和肌肉酸痛。

But this doesn’t mean the recipient is sick—

但這並不代表接種者生病了——

it means the vaccine is working.

這是代表疫苗正在發揮作用。

The body is producing antibodies to fight that viral protein,

身體會產生抗體來對抗這病毒蛋白，

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

然後它會繼續待著， 抵禦未來新冠肺炎的感染。

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

而由於在大多數的新冠病毒變體中 都很有可能有這種特殊的蛋白，

these antibodies should reduce the threat of catching new strains.

這些抗體應能降低感染新株的威脅。

This approach offers significant advantages over previous vaccines.

這方法比以前的疫苗有著明顯的優勢。

Traditional vaccines contain weakened versions of live viruses

傳統疫苗含有活性減低的病毒

or amputated sections of a virus,

或病毒的部分結構，

both of which required time intensive research to prepare

兩者都需要長時間的研究來準備，

and unique chemical treatments to safely inject.

亦需要獨特的化學處理才能安全注射。

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

但 mRNA 疫苗並非真的 含有任何病毒粒子，

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

因此不需因要為每種病毒 安全地作出調整而從頭構建。

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

事實上， 每種 mRNA 疫苗的成分都大致相同。

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

想像一種可靠、經過嚴格測試的疫苗，

可以通過更換單個成分 來治療任何疾病。

by swapping out a single component.

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

要治療一種新疾病， 研究人員會識別正確的病毒蛋白，

encode it into mRNA,

將其編碼為 mRNA，

and then swap that mRNA into the existing vaccine platform.

然後把該 mRNA 放到 疫苗平台中，取替現有的 mRNA。

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

這技術可讓新疫苗能夠在數週內開發，

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

在與疾病永無止境的對抗中，

成為人類一種靈活的新工具。