演说者：TED-Ed
演说题目：艾滋病为什么难治愈？
12月1日是世界艾滋病日。
今年，距离1981年全球首例艾滋病病例已经过去整整40年，但这种疾病仍然在人类社会流行。数据显示，截至2020年底，中国共有超过105万人感染艾滋病病毒，那为什么艾滋病那么难治愈呢？
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中英双语TED演讲稿
In 2008, something incredible happened: a man was cured of HIV. In over 70 million HIV cases, that was a first and, so far, a last.
在 2008 年发生了神奇的事情：一个男人的「人类免疫缺陷病毒」 (HIV) 被治好了。在超过 7,000 万笔 HIV 病例中这是首件，至今也是最后一件。
We don't yet understand exactly how he was cured. We can cure people of various diseases, such as malaria and hepatitis C, so why can't we cure HIV?
我们尚未了解他到底是如何被治愈的。我们可以治好很多种疾病像是疟疾或是 C 型肝炎，那么我们为什么无法治愈HIV呢？
Well, first let's examine how HIV infects people and progresses into AIDS.
首先让我们来检视HIV 对人体的影响以及如何进化成艾滋病 (AIDS)。
HIV spreads through exchanges of bodily fluids. Unprotected sex and contaminated needles are the leading cause of transmission. It, fortunately, cannot spread through air, water, or casual contact.
HIV 会透过体液交换散播出去。没有防护措施的性爱、受感染的针头是染病的首要原因。幸运的是它不能透过空气水分、或是一般接触来散播。
Individuals of any age, sexual orientation, gender and race can contract HIV. Once inside the body, HIV infects cells that are part of the immune system.
任何年龄层、性倾向、性别或是种族的单一个体都可能会感染到 HIV。一但进入了体内，HIV 会影响免疫系统的部分细胞。
It particularly targets helper T cells, which help defend the body against bacterial and fungal infections. HIV is a retrovirus, which means it can write its genetic code into the genome of infected cells, co-opting them into making more copies of itself.
它又特别针对辅助 T 细胞，这种细胞保护身体对抗细菌和霉菌感染。HIV 是一种「反转录病毒」，意即它可以将它的基因码写进受感染细胞的基因组拉拢这些细胞来复制更多病毒。
During the first stage of HIV infection, the virus replicates within helper T cells, destroying many of them in the process.
在第一阶段的 HIV 感染期间艾滋病治愈，病毒在辅助 T 细胞里面做复制，在过程里摧毁掉大量的辅助 T 细胞。
During this stage, patients often experience flu-like symptoms, but are typically not yet in mortal danger.
在这个阶段病患经常遭受到类似流行感冒的症状，但是通常还不会有致命的危险。
However, for a period ranging from a few months to several years, during which time the patient may look and feel completely healthy, the virus continues to replicate and destroy T cells.
然而在几个月到数年的期间里，病患也许看起来或感觉上是完全健康的，病毒继续在复制本身并摧毁辅助 T 细胞。
When T cell counts drop too low, patients are in serious danger of contracting deadly infections that healthy immune systems can normally handle. This stage of HIV infection is known as AIDS.
当辅助 T 细胞的数量下降到太低时，病患就会有受到感染而丧命的极度危险艾滋病治愈，那是健康的免疫系统通常可以解决的。这阶段的 HIV 感染就是你我熟知的艾滋病。
The good news is there are drugs that are highly effective at managing levels of HIV and preventing T cell counts from getting low enough for the disease to progress to AIDS.
好消息是有一些药在控制 HIV 的程度有高度成效，并防止辅助 T 细胞的数量降低到足以让病情演变成艾滋病。
With antiretroviral therapy, most HIV-positive people can expect to live long and healthy lives, and are much less likely to infect others.
有了抗反转录病毒疗法，大部分的 HIV 阳性反应者能预期活得长久又健康，而且不太会感染给他人。
However, there are two major catches. One is that HIV-positive patients must keep taking their drugs for the rest of their lives. Without them, the virus can make a deadly comeback.
不过有两个大问题。第一、 HIV 阳性反应患者在往后的日子里一定要持续服药。少了这些药，病毒就会回复而且致命。
So, how do these drugs work? The most commonly prescribed ones prevent the viral genome from being copied and incorporated into a host cell's DNA.
这些药如何发生作用呢？最常开出的药能避免病毒的基因组复制及被整合进宿主细胞的 DNA 里头。
Other drugs prevent the virus from maturing or assembling, causing HIV to be unable to infect new cells in the body.
其他的药则不让病毒成熟或是组合，造成 HIV 无法感染身体的新细胞。
But HIV hides out somewhere our current drugs cannot reach it: inside the DNA of healthy T cells. Most T cells die shortly after being infected with HIV.
但是 HIV 深藏于最新药方仍无法碰触的某处：健康的辅助 T 细胞的 DNA 里面。大部分的辅助 T 细胞感染到 HIV 很快就会死亡
But in a tiny percentage, the instructions for building more HIV viruses lie dormant, sometimes for years.
不过在极少百分比的情形下，制造更多 HIV 病毒的指令会潜伏，有时候还会长达数年。
So even if we could wipe out every HIV virus from an infected person's body, one of those T cells could activate and start spreading the virus again.
因此即便我们可以将所有的 HIV 病毒赶出受感染者的身体，潜伏指令的辅助 T 细胞能激活并再次开始传播病毒。
The other major catch is that not everyone in the world has access to the therapies that could save their lives.
另一个问题就是并非世界上的所有人都能拿到可能救其一命的疗法。
In Sub-Saharan Africa, which accounts for over 70% of HIV patients worldwide, antiretrovirals reached only about one in three HIV-positive patients in 2012.
在亚萨哈拉非洲有着世界上超过 70% 的 HIV 病患，2012 年抗反转录病毒疗法只能及于大约1/3 的 HIV 阳性反应病患。
There is no easy answer to this problem. A mix of political, economic and cultural barriers makes effective prevention and treatment difficult.
这个问题并不容易解决。夹杂了政治和经济还有文化的隔阂，使得有效的防护以及治疗很难做到。
And even in the U.S., HIV still claims more than 10,000 lives per year. However, there is ample cause for hope. Researchers may be closer than ever to developing a true cure.
即便在美国每年 HIV 照样夺走一万多条人命，然而还是有足够的理由可以盼望，研究人员比以前更有可能做出真正的解药
One research approach involves using a drug to activate all cells harboring the HIV genetic information.This would both destroy those cells and flush the virus out into the open, where our current drugs are effective.
这将会一并摧毁这些细胞以及让病毒赶出细胞外，有一个研究方法涉及利用药物活化所有藏着 HIV 基因信息的细胞，在那里最新的药物是起的了作用的。
Another is looking to use genetic tools to cut the HIV DNA out of cells genomes altogether.
另一个则是打算利用基因工具，把 HIV 的 DNA 全部赶出细胞的基因组。
And while one cure out of 70 million cases may seem like terrible odds, one is immeasurably better than zero.
7,000 万个案例里才一个被治愈可能看起来是非常糟糕的机率，一个还是远远胜过零个。
We now know that a cure is possible, and that may give us what we need to beat HIV for good.
现在我们知道了治愈是有可能的，这就可能带给我们想永远解决掉 HIV 所需要的东西。
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