Now, technically, everyone with COVID-19 starts out symptom-free, or presymptomatic.

现在，从技术上来看，每一个新冠感染者在一开始都是没有症状的，或者说正处于一种症状前的状态。

That is what the second strand of research on the asymptomatic and presymptomatic transmission of SARS-COV-2 deals with.

这是关于SARS-COV-2无症状和症状前传染的第二部分研究。

I've heard numbers it could be as much as half of all transmissions are basically presymptomatic.

我听说有数字可能多达一半的传播基本上是症状前的。

Yeah, if you count presymptomatics, then most of the studies show that's like at 40 percent, and we also have never symptomatics.

BG：是的， 如果你算上症状前，那么大多数研究表明大约有 40%， 而且我们也从未出现过症状。

This can often be confused with the term presymptomatic, which means that a person has a virus, but isn’t showing any symptoms yet.

这通常会与症状前一词混淆，症状前意味着一个人感染了病毒， 但尚未表现出任何症状。

And so if you add in the never symptomatic to the presymptomatic, do you get above 50 percent of the transmission is actually from nonsymptomatic people?

因此， 如果将无症状的人加到有症状的人身上，是否有超过 50% 的传播实际上来自无症状的人？

With incubation times varying depending on what virus you’re talking about, only time can really tell whether a presymptomatic person will end up having symptoms or not.

潜伏期因病毒种类而异，只有时间才能真正判断未出现症状的人最终是否会出现症状。

It's increasingly clear that a lot of the spread is occuring through presymptomatic people, folks that are in the incubation period, many of whom are not at high risk themselves.

越来越明确的是，许多传播源是临床症状前期患者，当时这些人处于潜伏期，他们中的许多人本身并不是患病的高风险对象。

The amount of presymptomatic and never symptomatic spread and the fact that it's not coughing, where you would kind of notice, " Hey, I'm coughing" -- most respiratory diseases make you cough.

症状前和无症状传播的数量以及它不咳嗽的事实，你会注意到， “嘿，我在咳嗽” ——大多数呼吸道疾病都会让你咳嗽。