Some medical experts in Hong Kong have devoted their careers to the study of micro microbiology and viruses, after the traumatic episode of SARS. These are the people I will tend to listen to, on this topic. For example, Yeung Kwok Yung and Gabriel Leung.
And these Hong Kong specialists project the evolution of the infection in a way no Western newspaper (who mostly take the official government numbers at face value) dares to relate, it seems.
Widely different projections
Let’s take an example. (Note that I am not vouching for the accuracy of this source, and it is a forecast based on questionable assumptions. But I don’t understand why journalists in Europe and North America seem not to be taking that input into consideration.)
On 28 January, the head of the medical faculty of the CUHK University estimated the peak of the epidemic would probably be in April in China, and in May in Hong Kong. (Source in Cantonese is here.)
He also estimates the REAL number of cases was as follows on 25 January:
- People with symptoms in Wuhan only: 25,000 people
- “Hidden cases” (no symptoms yet): 44,000 people
In contrast, an expert from the Chinese government forecasts the peak might be reached in about 10 days. I am sure their model is good, but I’d like to know what their assumptions were.
Why the situation might become a full-blown epidemic soon
The numbers of infected people might shoot up dramatically this week. Here is why.
The incubation period seems to be up to 19 days (from infection until symptoms appear), based on the case of the Chinese lady who went to Wuhan and later went back to her home in Canada. Not “up to 14 days” as related so far.
[Update 31 Jan.: a Professor of microbiology at the University of Hong Kong Medical School said the incubation period might be longer than 14 days. Source in Chinese: click here.]
Such a long incubation is really scary. Here is why.
- Not everybody is tested. The test kits are not available in unlimited numbers. Most people who are still in incubation have not been tested.
- The “positive” cases detected so far are (1) people who have been in Wuhan and (2) people who have been in direct contact with someone coming from Wuhan.
- But what about the 3rd circle (those who have been in contact with someone who was herself infected by someone coming from Wuhan)? How many are they?? One can imagine tens of thousands of people starting to have symptoms over the next few days.
Let’s hope this is all wrong. All I am trying to do is to provide a balanced view. When the official forecasts seem to be too rosy, they invite this type of analysis…
Do people know how to take the right precautions?
I see a serious lack of information around these masks.
First, wearing a disposable facial mask helps, but in principle, they need to be changed every 3 to 5 hours.
Many people are wearing the same mask for several days. If there is no other option, it might be fine, but the mask needs to be disinfected with alcohol (which will break the fibers a little, every time) and be dried in the open air (if possible under the sun).
Second, not all surgical masks are the same. Real medical-grade masks come with a performance number, based on an ASTM standard. The performance on BFE (Bacteria Filtration Efficiency) should be 95% or more. A good one is 99.8%. (Note: the risk here is a virus, but this virus may attach itself to a bacteria.)
Third, users should not touch the surface of the mask. Grab it by the elastics.
If you need to remove and re-use the mask, fold it (keep the inner side on the inside of the fold) and place it inside an envelope.
Fourth, wearing glasses or goggles helps, too. The eyes are a common entry point for the virus.
And, above all, keep hands clean. People who touch their eyes with their hands in a dangerous area have a high risk of getting infected.
The best ways to disinfect surfaces are solutions with at least 80% alcohol concentration, or with a 1 to 99 ratio of bleach to water. That ratio can be 1 to 65 if you want the same cleanliness level as a hospital.
I hope this advice is useful. Feel free to pass it to your staff or your suppliers in China. And let me know in the comments if I am forgetting something important.
Also, remember to read my prior post on the topic: What the Wuhan Virus Means for Importers of China Products, where I give some suggestions based on what I’m seeing about the possible effects of the virus on your supply chain.
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The mask comment seems directed to those flimsy surgical masks. Most people here have quality N95 masks. You might want to make that clear.
It would also help to cite sources for all the information. There is a ton of false information going around on Wechat right now. It’s really dispiriting to see people you know forward some crap, you call them out on it, and they reply “well I was just putting it out there.”
Renaud Anjoran says
N95 masks are great. But the 3-layer masks with BFE > 95% are generally good enough. And remember, there is a lot of other precautions to take — masks alone won’t drive the risk of getting infected down to zero.
Most of the advice I wrote above was confirmed by someone who studied microbiology (MSc level) and worked for 10 years in that field. Do you mean that some of what I wrote above is “crap”?
I mean that it’s unsourced, and how is the layman to tell the difference between what you wrote and crap?
Do N95 masks need the care that the cheap ones do? Like I said, most people here have them and it would be good to point them to some good sourced information, since this epidemic is going to go on for a while.
Renaud Anjoran says
I get your point. Unfortunately, this is someone I wrote with help from our team, and it doesn’t come from The Lancet. 🙂
I am not sure about N95 (I suspect the same hacks would be needed). As I wrote above, we suggest the most important criterion would be BFE . 95% and ideally > 99%.
I am afraid people who opt for N95 masks are over-shooting. And, since it is much harder to breathe through them, people are more likely to remove them (or pull them down under the chin)… which leads to much higher risks.
As a Hazmat card holder I can tell you the N95 masks while might be better than nothing dont guarantee you anything. A 99.8% filter rating is for particulates traveling through the mask. These masks do not seal in anyway and are a horrible idea for any kind of real threat. It horrifies me that people think they work at all. The proper way to protect yourself is a full face respirator fitted to your face. Or a supplied air system for really serious stuff over the ppm limits of a full face setup. Personally I think hospitals etc have opted for a feel good look of the paper masks when in reality a full face respirator is really what should be used. But they look menacing so let’s not wear those. Ugh.. anyway I’m praying for the Chinese people and those stateside.