经济学人下载:新冠疫苗—艰难与困苦(2)

America's behaviour is not much better. Again, the approach behind the product approved is reasonable in principle, but insufficiently tested.
美国的做法也好不到哪去。同样，被批准产品背后的方法在原则上是合理的，但是没有经过充分的测试。

Convalescent plasma therapy transfuses blood plasma from those who have recovered from an infection
恢复期血浆疗法将新冠康复者的血浆

(and which is therefore rich in antibodies against whatever had infected them) into patients with the illness to be treated.
（因此血浆中富含抗体来对抗感染它们的病毒）输入待治疗患者体内。

As Soumya Swaminathan, chief scientist of the World Health Organisation (WHO), observes,
正如世界卫生组织（WHO）的首席科学家Soumya Swaminathan所观察，

this tactic has been used to treat infectious diseases for over 100 years, and is effective against some, but not others.
在一百多年前，这种策略被用于治疗感染性疾病，且对一些疾病有效，一些无效。

Trials of it as a treatment of covid-19 are therefore under way around the planet,
所以将它作为一种治疗新冠的方法正在全球进行中，

but Dr Swaminathan says the results so far are "not conclusive", and the trials themselves have been small.
但Swaminathan博士表示到目前为止，结果“并不具备决定性”，而且试验本身规模也很小。

As a result, the WHO considers it an "experimental therapy".
因此，WHO将它看做是一种“实验治疗”。

Not so, apparently, the FDA. Mr Trump made his announcement with Dr Hahn on the same platform. Two things have upset people about this.
显然，FDA并非如此。特朗普和哈恩博士在同一平台发表声明。两件事让人们对此感到不安。

One is that the basis for the emergency approval was an observational study of ways of administering plasma
一个是紧急批准的基础是一项血浆管理方法的观察研究

(either less or more than three days after diagnosis) rather than a randomised controlled trial
（诊断后少于或多于三天）而不是随机对照试验

in which some patients were given a placebo instead of the treatment under test.
在对照实验中，一些患者被给予安慰剂，而不是实施治疗。

The other is that, even granted this difference, the advantage seen in the study in question was too inconclusive to justify the approval given.
另一个是，即使存在这种差异，在该研究中看到的优势也不是决定性的，所以无法证明批准是合理的。

Dr Hahn described the benefits of treating early with convalescent plasma by saying that,
哈恩是这样描述早期用恢复期血浆疗法治疗的好处的：

"if the data continue to pan out, of 100 people who are sick with covid-19, 35 would have been saved because of the administration of plasma".
“如果数据证明是成功的，那么在100名感染新冠的患者中，有35人会因为使用血浆而获救”。

Jonathan Reiner, a professor of medicine at the George Washington University Medical Centre,
乔治华盛顿大学医学中心的医学教授Jonathan Reiner

tweeted that this was "shockingly wrong", and that the actual figure was 3.2.
发推文称，这是“令人震惊的错误”，实际数字是3.2。

Dr Hahn has since clarified that he confused the relative reduction in risk of mortality
哈恩博士随后澄清说，他混淆了死亡率风险的相对降低率

(of 35% between the two arms of the study) with an absolute risk reduction. That is a pretty fundamental mistake.
（两组研究中降低了35%）和绝对危险度降低率。这是一个非常基本的错误。

Extrapolating from a single case is risky, but this one calls into question how long someone who recovers from infection retains immunity from re-infection.
从单个病例进行推断是有风险的，但这引发了一个问题，新冠康复者的免疫力能够维持多久。

The answer is crucial to understanding how herd immunity to the virus develops in populations,
这个答案对理解，对病毒的群体免疫力是如何在群体中产生的很关键，

and may also have implications for vaccine development.
且也可能对疫苗开发有影响。

Doctors will now be looking hard for similar examples, so that such understanding can be improved.
现在，医生们将努力寻找类似的例子，以便提高对这方面的理解。