askST: When will the coronavirus outbreak ease?

An elderly lady in a wheelchair wearing a mask at Tan Tock Seng Hospital, on Feb 4, 2020.
An elderly lady in a wheelchair wearing a mask at Tan Tock Seng Hospital, on Feb 4, 2020.ST PHOTO: KUA CHEE SIONG

SINGAPORE - As Singapore hunkers down for the long term with the outbreak of the coronavirus originating from Wuhan, many readers have asked about how long the situation is likely to last, and why the death toll in China has been so high compared to other countries.

The Straits Times spoke to Professor Paul Tambyah, senior consultant at the Division of Infectious Diseases at the National University Hospital's University Medicine Cluster, to find out more.

Q: How long will the coronavirus situation last?

A: The virus will likely die down when the hot season hits China, said Prof Tambyah.

He said: "What happened with severe acute respiratory syndrome (Sars) (was) that the numbers kept increasing and increasing, then when the hot weather came to Beijing, all of a sudden the numbers just plummeted."

Sars, which hit Singapore in 2003, is a disease from the same family of viruses as the new coronavirus.

Sars appeared in November 2002 in the southern Chinese province of Guangdong.  It infected more than 5,300 people and killed 349 people in  China. Nearly 800 people, including 33 in Singapore, succumbed to the disease worldwide.

 Prof Tambyah said that the hot weather has been shown to get rid of other respiratory viral infections as well.

For instance, in temperate countries, the flu is a winter disease which goes away when the hot weather begins.

"I'm pretty confident we'll have a quiet June," he said.

Q: If an infected person coughs or sneezes onto a handrail or surface, how long can the virus survive there?

A: While experts do not know the answer for this specific virus, Prof Tambyah said that previous studies done on the common cold coronavirus show that it depends on the temperature and humidity in the area.

In these studies, at 6 deg C, the infectious virus particles could survive for close to 100 hours.

 

But at 30 deg C, the particles were gone in about an hour or two.

"At high temperature, high humidity, the virus is gone very quickly. At low temperature, low humidity, it can stay for quite a while," he said.

This is why being in a well-ventilated, non air-conditioned room might lower the risk of getting infected than being in an enclosed, air-conditioned room, he said.

Q: Why is the mortality rate so high in China compared with the rest of the world?

A: The virus was in China long before it was anywhere else, said Prof Tambyah, and therefore there was more time for the situation to develop there.

As of Wednesday (Feb 5), the coronavirus has killed 492 people worldwide, with 490 deaths recorded in China.

He said: "Remember, what happens with this virus is you get infected, there's an incubation period, then you start getting symptoms... and then somewhere on day seven, eight, or nine, if you're unfortunate and in the 20 per cent who's going to get into complications, that's when it starts going downhill."

 
 

He added that the rest of the world has not been hit as bad as China due to a "lag period". China reported its first cases in December last year.

"We've seen it in other countries - once you start seeing cases, then you're going to start seeing deaths," he said.

But another possible reason for the higher death rate in China is that hospitals in Wuhan have been overwhelmed, due to the nature and magnitude of the outbreak, making it difficult for medical workers to treat patients properly, said Prof Tambyah.

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