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。

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，当时处于潜伏期，他们中的许多本身不是患病的高风险对象。

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

是关于SARS-COV-2无症状和症状前传染的第二部分研究。

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.

无症状和始终无症状的传播数量，以及事实是它不会引起咳嗽——你通常会注意到“嘿， 我咳嗽了” ——大多数呼吸系统疾病都会让你咳嗽。

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

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

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最终是否会出现症状。

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

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

我听说有可能高达一半的传播都是基本属于无症状期的传播。

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

比尔·盖茨：是的， 如果你算上无症状期的传播者，那么大多数研究表明个比例大约是40%， 我们还有从未出现症状的。