Friday, 7 February 2020

The Fear of Living Dangerously (or "Who's afraid of the Big Bad Wu(han) virus?")

The 2019-nCoV is known as the Wuhan virus.

And as for "who's afraid of the Wuhan virus?". The answer is, Singaporeans. And everyone else.

Shouldn't we be afraid?

Yes and no.

Just how dangerous is the Wuhan virus?

That depends on how you define "dangerous".

If you take a single factor, say fatality, and compare it, the fatality of the Wuhan virus is about 3%.

That is, of 100 persons infected, 3 will die.

Is that high?

Well, SARS had a fatality of about 10%. And that is considered high.

And the seasonal flu has a fatality of about 0.1%, which because of the endemic nature of the seasonal flu, is something that we have gotten used to. Though some people may be surprised to know that there are people who die from the "common" flu.

The seasonal flu affects LOTS of people - millions. And in the US, it is expected that 8000 people or more will die from the flu this year.

So far the Wuhan virus has killed about 600 people. And infected about 30,000 people (figures are rounded up at the time of this writing. It will probably go up. Here is the website.).

The point is using a single factor like fatality (or death rate) is not helpful.

This video provides some factual, unsensationalised information:

Firstly, the transmissibility (or infectiousness) of the Wuhan virus is about 2. That means each person with the wuhan virus might on average infect two other persons. Is this high? Well, measles has a transmissibility of about 15. Seasonal flu has a transmissibility of about 1.

So the Wuhan virus is (probably) more infectious than flu.

And part of the reason seems to be that the Wuhan virus may be transmissible pre-symptomatic. That is, before you have symptoms of the illness, you can infect others.

[Edit: It may not be completely asymptomatic. There may be some mild or non-specific symptoms. But it may be so mild that some infected may simply ignore it.]

Which is troubling, and one of the reason why this virus has been harder to contain than SARS.

And why face masks are not going to be effective.

Singaporeans are rushing to buy and stock up on masks. It's not going to help. Not the way Singaporeans are hoping though:
...surgical masks and N95 respirators.
N95 respirators filter out most airborne particles from the surrounding air, preventing wearers from breathing in particles down to 0.3 microns in diameter. These types of masks are often used when air quality is poor due to wildfire smoke or pollution, and they’re designed to fit tightly against one’s face.
However, the coronavirus measures 0.12 microns in diameter.
Surgical masks, meanwhile, are designed to keep large particle droplets and splatter from passing from a person’s mouth to nearby surfaces or people. So they’re primarily meant to keep healthcare providers from spreading their own mouth-borne germs to patients. 
Which is why the government has not bothered to push for N95 masks. Those masks are more expensive, and in this case would not filter out the virus.

In any case, the recommendation to use surgical masks is to prevent those who are sick from transmitting their germs to others. So the masks is to be used only if you are sick.

But that's not how Singaporeans are using the masks.

And even if masks are worn by those who are ill, if they have been infected by the virus, they would be infectious BEFORE they had symptoms so before they knew to wear a mask.

So masks may not be effective.

But it is better than nothing right?

Maybe not.
Q: Does wearing masks and gloves help prevent infections?
A: First of all, masks. There’s very limited evidence of benefit, if any, in a casual situation. Masks are useful for those who are unwell to protect other people from them. But wearing a mask all the time will be ineffective. It will allow viruses to be transmitted around it, through it and worse still, if it becomes moist it will encourage the growth of viruses and bacteria. Gloves are probably even worse, because people put on gloves and then touch everything they would have touched with their hands. So it just becomes another way of transferring micro-organisms. And inside the gloves, your hands get hot and sweaty, which is a really good environment for microbes to grow.

And the fatality rate of 3% is probably a high estimate.

In this early stage, most of the confirmed cases are severe cases. And of these severe cases, there have been deaths. And these deaths as a percentage of the severe cases will be higher than if ALL those other cases which have not been reported because the symptoms are so mild that the infected has no bothered to report or seek medical attention.

For example, the seasonal flu in the US has had 19 million infection, 180,000 hospitalisation, and 10,000 deaths this season. 10,000 of 19 million is 0.05%. BUT 10,000 of 180,000 is 5.6%.

The point is, this Wuhan virus may not warrant the panic and anxiety that we feel.

Also, China had lockdown Wuhan and Hubei to contain the virus. And this has caused Hubei to bear the burden of suffering this new illness. The death rate in Hubei is 3%. It is only 0.16% for the rest of China.

So the 3% fatality rate (in Hubei) may be due to circumstances - the resources in Hubei/Wuhan are stretched and the infected are not getting adequate/appropriate medical attention. And the "real" fatality rate, if appropriate medical attention not constrained by quarantine or other limitations, may be a lot lower.

Or maybe the Chinese are covering up the REAL  figures?

There was a "leak" by Tencent that provided much higher figures of death and infection in China. The "leak" gave deaths of over 24,000, and infections of over 150,000 in China, which gives a fatality rate of 16%.

But this is unsubstantiated. If the fatality rate is really as high as 16%, then Singapore with 30 cases should have 4 or 5 deaths. Japan with 86 cases should have 13 deaths. In both countries there are no deaths so far.

So the "leaked" figures are base on all other analyses, unsubstantiated. And even if it were true, it may be the Hubei Quarantine effect - China letting Hubei/Wuhan bear the disproportionate burden of the infection. And if so, it does not translate to a 16% fatality for the rest of the world.

So what should you do?

First, don't panic.

Second, wash your hands often, and don't touch your face with unwashed hands. You can use hand sanitisers but understand that "anti-bacterial" hand sanitisers are targeted at BACTERIA. This is a VIRUS. Your sanitisers should be alcohol based, because the alcohol is what will kill viruses.

Third, if you are unwell, stay home. If you have to go out, wear a mask. This is not for your protection. It is to prevent panic in others.

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