Why it’s so hard to cure HIV/AIDS - Janet Iwasa

為什麼要治好 HIV 或 AIDS 是如此困難？

譯者: Harry Chen 審譯者: Regina Chu

In 2008, something incredible happened: a man was cured of HIV.

在 2008 年發生了神奇的事情：一個男人 被治好了「人類免疫缺陷病毒」 (HIV)

In over 70 million HIV cases, that was a first and, so far, a last.

在超過 7,000 萬筆 HIV 病例中 這是首件，至今也是最後一件

We don't yet understand exactly how he was cured.

我們尚未瞭解他到底是如何被治癒的

We can cure people of various diseases, such as malaria and hepatitis C,

我們可以治好很多種疾病 像是瘧疾或是 C 型肝炎

so why can't we cure HIV?

那麼我們無法治癒 HIV 是什麼原因呢？

Well, first let's examine how HIV infects people

首先讓我們來檢視 HIV 對人體的影響

and progresses into AIDS.

以及如何進化成愛滋病 (AIDS)

HIV spreads through exchanges of bodily fluids.

HIV 會透過體液散播出去

Unprotected sex and contaminated needles are the leading cause of transmission.

沒有防護措施的性愛、受感染的針頭 是染病的首要原因

It, fortunately, cannot spread through air, water, or casual contact.

幸運的是它不能透過空氣 水分、或是一般接觸來散播

Individuals of any age, sexual orientation, gender and race

任何年齡層、性傾向、性別 或是種族的單一個體

can contract HIV.

都可能會感染到 HIV

Once inside the body, HIV infects cells that are part of the immune system.

一但進入了體內 HIV 會影響免疫系統的部分細胞

It particularly targets helper T cells,

它又特別針對輔助 T 細胞

which help defend the body against bacterial and fungal infections.

這種細胞保護身體 對抗細菌和黴菌感染

HIV is a retrovirus,

HIV 是一種「反轉錄病毒」

which means it can write its genetic code into the genome of infected cells,

意即它可以將它的基因碼 寫進受感染細胞的基因組

co-opting them into making more copies of itself.

拉攏這些細胞來複製更多病毒

During the first stage of HIV infection,

在第一階段的 HIV 感染期間

the virus replicates within helper T cells,

病毒在輔助 T 細胞裡面做複製

destroying many of them in the process.

在過程裡摧毀掉大量的輔助 T 細胞

During this stage, patients often experience flu-like symptoms,

在這個階段病患經常 遭受到類似流行感冒的症狀

but are typically not yet in mortal danger.

但是通常還不會有致命的危險

However, for a period ranging from a few months to several years,

然而在幾個月到數年的期間裡

during which time the patient may look and feel completely healthy,

病患也許看起來 或感覺上是完全健康的

the virus continues to replicate and destroy T cells.

病毒繼續在複製本身 並摧毀輔助 T 細胞

When T cell counts drop too low,

當輔助 T 細胞的數量下降到太低時

patients are in serious danger of contracting deadly infections

病患就會有受到感染 而喪命的極度危險

that healthy immune systems can normally handle.

那是健康的免疫系統通常可以解決的

This stage of HIV infection is known as AIDS.

這階段的 HIV 感染 就是你我熟知的愛滋病

The good news is there are drugs that are highly effective

好消息是有一些藥

在控制 HIV 的程度有高度成效

at managing levels of HIV

and preventing T cell counts from getting low enough

並防止輔助 T 細胞的數量 降低到足以讓病情演變成愛滋病

for the disease to progress to AIDS.

With antiretroviral therapy,

有了抗反轉錄病毒療法

most HIV-positive people can expect to live long and healthy lives,

大部分的 HIV 陽性反應者 能預期活得長久又健康

and are much less likely to infect others.

而且不太會感染給他人

However, there are two major catches.

不過有兩個大問題

One is that HIV-positive patients must keep taking their drugs

第一、 HIV 陽性反應患者 在往後的日子裡一定要持續服藥

for the rest of their lives.

Without them, the virus can make a deadly comeback.

少了這些藥，病毒就會回復而且致命

So, how do these drugs work?

這些藥如何發生作用呢

The most commonly prescribed ones prevent the viral genome from being copied

最常開出的藥能避免 病毒的基因組複製

and incorporated into a host cell's DNA.

及被整合進宿主細胞的 DNA 裡頭

Other drugs prevent the virus from maturing or assembling,

其他的藥則不讓病毒成熟或是組合

causing HIV to be unable to infect new cells in the body.

造成 HIV 無法感染身體的新細胞

But HIV hides out somewhere our current drugs cannot reach it:

但是 HIV 深藏於 最新藥方仍無法碰觸的某處

inside the DNA of healthy T cells.

健康的輔助 T 細胞的 DNA 裡面

Most T cells die shortly after being infected with HIV.

大部分的輔助 T 細胞 感染到 HIV 很快就會死亡

But in a tiny percentage,

不過在極少百分比的情形下

the instructions for building more HIV viruses lies dormant,

製造更多 HIV 病毒的指令會潛伏

sometimes for years.

有時候還會長達數年

So even if we could wipe out every HIV virus from an infected person's body,

因此即便我們可以將所有的 HIV 病毒趕出受感染者的身體

one of those T cells could activate and start spreading the virus again.

潛伏指令的輔助 T 細胞 能激活並再次開始傳播病毒

The other major catch is that not everyone in the world has access to the therapies

另一個問題就是並非世界上的 所有人都能拿到可能救其一命的療法

that could save their lives.

In Sub-Saharan Africa, which accounts for over 70% of HIV patients worldwide,

在亞薩哈拉非洲 有著世界上超過 70% 的 HIV 病患

antiretrovirals reached only about one in three HIV-positive patients in 2012.

2012 年抗反轉錄病毒療法只能及於 大約1/3 的 HIV 陽性反應病患

There is no easy answer to this problem.

這個問題並不容易解決

A mix of political, economic and cultural barriers

夾雜了政治和經濟還有文化的隔閡

makes effective prevention and treatment difficult.

使得有效的防護以及治療很難做到

And even in the U.S., HIV still claims more than 10,000 lives per year.

即便在美國 每年 HIV 照樣奪走一萬多條人命

However, there is ample cause for hope.

然而還是有足夠的理由可以盼望

Researchers may be closer than ever to developing a true cure.

研究人員比以前更有可能 做出真正的解藥

One research approach involves

有一個研究方法涉及

using a drug to activate all cells harboring the HIV genetic information.

利用藥物活化所有藏著 HIV 基因資訊的細胞

This would both destroy those cells and flush the virus out into the open,

這將會一併摧毀這些細胞 以及讓病毒趕出細胞外

where our current drugs are effective.

在那裡最新的藥物是起的了作用的

Another is looking to use genetic tools

另一個則是打算利用基因工具

to cut the HIV DNA out of cells genomes altogether.

把 HIV 的 DNA 全部 趕出細胞的基因組

And while one cure out of 70 million cases may seem like terrible odds,

7,000 萬個案例裡才一個被治癒 可能看起來是非常糟糕的機率

one is immeasurably better than zero.

一個還是遠遠勝過零個

We now know that a cure is possible,

現在我們知道了治癒是有可能的

and that may give us what we need to beat HIV for good.

這就可能帶給我們想永遠解決掉 HIV 所需要的東西