One Chinese government expert, Zhong Nanshan, says the epidemic may peak towards the second week of February.

一位中國政府的專家，鍾南山表示該傳染病可能在二月的第二週達到高峰。

But academics from the University of Hong Kong, think that's more likely to happen sometime in April or May.

但是香港大學的學者們則認為，高峰應該會發生在四月或五月。

There is so much uncertainty about this new virus, that it's almost impossible to make accurate predictions.

這種新病毒充滿了不確定性，因此幾乎無法做出精準的預測。

First of all, we don't know how many people have the virus right now.

首先，我們不知道目前有多少人帶原。

Reported cases have surged in the last few days, but that could be down to increased surveillance and testing.

在過去幾天確診的病例激增，但那很有可能是歸因於檢查和測試的增加。

There could still be thousands who aren't coming forward, either because they have mild symptoms or because they feel safer waiting it out at home.

可能還有上千人沒有坦言病情，或許是因為他們症狀輕微，也或許是因為他們覺得在家等著病情痊癒更安全。

Next, we don't know how easily the virus spreads.

接著，我們不知道這病毒究竟有多容易散播。

On average, it looks as though each infected person has the ability to infect two or three more.

目前看來，平均一位被感染者有能力傳染給兩至三人，或更多。

This is known as the reproduction number, and it's significant.

這叫做再生數，而且它非常重要。

Up until now, the number of infections is thought to have doubled every six days.

到現在為止，感染人數被認為每六天就會翻倍。

That gives us some really big numbers.

這提供了我們一些非常大的數字。

Mass quarantines, the extended public holiday, plus putting the public on high alert may slow the spread of disease from person to person, but it's hard to know how effective these measures will be because of another big unknown.

大規模隔離、延長假期再加上使大眾提高警覺，或許能夠減緩人傳人的速度，但是由於另一個重大的未知，我們很難知道這些措施的效果如何。

We don't yet know how long it takes for an infected person to show symptoms, nor whether that person can pass the disease on before showing any signs of illness.

我們還不知道一位被感染的人需要經過多久才會顯現症狀，也不知道那個人在出現任何病徵前是否能傳播這個疾病。

This raises doubts over the value of temperature screening, which has been a key control so far.

這使得體溫檢查的價值遭到懷疑，它是迄今為止最關鍵的控制方法。

Finally, we don't know how severe the virus is.

最後，我們不知道這個病毒究竟有多嚴重。

It seems to be spreading faster and wider than SARS, which infected 8,000 people over eight months.

看起來它比 SARS 散播得更快、更廣，而 SARS 在八個月內感染了超過 8,000 人。

This coronavirus has gone past that number in less than two months.

這個冠狀病毒在不到兩個月內就超過了那個數字。

Around 20 % of patients progressed from fever and a dry cough to more severe symptoms such as pneumonia and organ failure with around 4% dying.

大約百分之 20 的病患從發燒和乾咳發展成更嚴重的症狀，像是肺炎和器官衰竭，大約百分之 4 的人死亡。

But at the start of an outbreak serious cases tend to appear first—like the tip of an iceberg.

不過在疾病爆發的初始，通常嚴重的案例會先出現，就像冰山的一小角。

So the rate of severe illness may drop as milder cases turn up.

因此重症的比率可能隨著較輕微案例的出現而下降。

In SARS, the death rate was about 10%.

SARS 時期，死亡率大約是百分之 10。

But even if this new virus has a lower mortality rate, it could still kill more people because it causes more infections.

然而即便這種新病毒有著較低的死亡率，仍可能奪走更多條性命，因為它帶來更多感染數。

And while it's spreading, it might also mutate to become more or less virulent.

而在它散播的同時，它也有可能變異得更加致命亦或相反。

We are better prepared than we were in 2003 during the SARS epidemic, but this still looks like a monumental global health challenge.

比起 2003 年 SARS 的流行期間，我們準備得更完善，但這次看起來仍是全球健康的一個巨大挑戰。

And until we know more about the virus itself, its final impact will be hard to predict.

而直到我們能夠更了解這個病毒前，其最終影響仍是難以預測的。