This estimate is broadly consistent with that published last week by a Imai et. al. [1] That previous work looked at foreign cases up to 18th January, and concluded the number of contagious cases in Wuhan as of that date is likely in the range of 1000 to 9700.
This paper gives estimates of Wuhan-area cases ranging from 7600 to 43600 for January 26.
A doubling time of 6 days was estimated for the pre-lockdown phase of the Wuhan epidemic. [2] That gives a factor of 2.5 increase in cases between Jan. 18 and 26.
Unfortunately the newer estimated case numbers are somewhat higher than 2.5 times as many; probably the older number were too low.
Note the estimated rate of increase is much LOWER than one would naively get from looking at the officially confirmed case numbers. Confirmed cases have been more than doubling every two days. This growth rate of confirmed cases is really the rate of increase of China's capability of carrying out confirmation labwork.
There exported case research shows there is still a huge backlog of unconfirmed cases to be identified in the Wuhan area.
The median estimate of the size of the outbreak by Imai et al as of Jan 18 is 4,000; the new median estimate by Chinazzi et al as of Jan 26 is 21,300 (assuming a catchment population of 20M, their middle case). If both median estimates happen to be spot-on, the size of the outbreak would have grown by a factor of 5.3 between those two dates.
I don't think you've got the right conclusion. The earlier estimate of the total cases was too low.
Probably the newer estimate of total cases is ALSO biased too low. The reason for underestimate is they are assuming international surveillance found all exported cases. The paper describes this shortcoming:
The estimates contained in this report have been constantly growing with respect to older
versions compiled with the data available at previous dates. This is because the number of
detected cases at International locations and a travel history from Wuhan city has nearly
tripled in the last week. It is worth stressing that this is not implying that the epidemic is
growing at the same rate. The estimated size of the outbreak refers to all cases occurred in
the area since the beginning of the outbreak, and notification and detection delays may play
an important role that, at the moment, do not allow the evaluation of the epidemic growth
rate.
This is interesting. China can't cover up the true scale of the outbreak because the rate of infection overseas quickly gives the game away if they are publishing very low estimates of domestic infection.
It’s pretty hard to cover up the dimension of an outbreak after it gets outside your borders. There are many things you can use to infer what the real dimension is likely to be.
That being said, it’s also entirely likely that even the Chinese known exactly how many cases there are:
1. Cases aren’t detected unless you feel sick enough to go to the doctor
2. Even if you go to the doctor, the symptoms have to be strong enough for the doctor to order the specific test. This is a bigger factor in the early days. After the alert is given they likely start testing everyone, at least until the outbreak is large enough that it becomes moot
3. The big question (that I haven’t seen answered yet) if how long the assymptomatic incubation period is. In other words how long can you spread it before realizing you’re sick.
In the end, the factor that will determine how large of a global outbreak were actually dealing with is now transmissible it is from person to person. From what I’ve seen all foreign (outside China) cases have been traced back to China, meaning that person to person transmission isn’t a large factor yet. If/when it does become a factor that’s when the real containment “game” starts...
> - how useful are those surgical masks for preventing getting sick / infecting others?
After SARS the CDC published updated guidance on masks in relation to Influenza in general. TL;DR is use regular paper masks for general population, hospital staff, and patients. N95 masks for staff doing intake and direct treatment. This addresses the primary problem with N95 masks: hospitals running out.
The "N95" rating means it filters 95% of particles 3 microns or larger. Research showed only Influenza particles 4 microns or larger carried enough RNA to replicate successfully.
You can also read Respiratory Protection for Healthcare Workers in the Workplace Against Novel H1N1 Influenza A: A Letter Report published by National Academies Press for all the details.
I was a bit frustrated when I couldn't easily find an online guide to prevent the spread of coronavirus.. so I went ahead and compiled all the info I read and made this Coronavirus Prevention Guide http://stopcorona.org/
Hopefully it gets seen by enough people who will put the tips into practice and slow down the spread of the virus.
The theory is Wuhan Flu (there are actually a large number of "coronaviruses") is contagious before symptoms show, which is why it is so effective at spreading.
Preventing the spread basically comes down to avoiding people. I'm not sure that is great advice. The rest of this site is just things people should be doing anyway like washing their hands.
If you suspect that you were exposed to coronavirus or have it but are suffering from the milder symptoms, you should proactively self quarantine if you live with others, and wear a mask in public to avoid infecting others.
You made a guide homepage in the post I answerded to, which repeatedly mentions "if you have these symptoms". But the symptoms are not mentioned in the guide.
I think for a proper guide you should absolutely list the symptoms of corona virus at the introduction.
I searched in search engines. As far as I could find the corona virus symptoms are similar to pneumonia. The main symptoms are fever, cough and pain in the lungs.
This is not similar to flu symptoms which do not necessarily spread to the lungs.
I think it's frankly disgusting that the international community did not learn from SARS. As has been said before, to stop the spread of a virus, you need containment and isolation. All trafic to and from China should have been stopped at the first mention of a new corona virus emerging there until the point where it could be determined either to be contained properly, or it it's lethality and infection rate were considered low enough to not be a potential international risk.
Furthermore, I think China should get some very severe sanctions from the international community for covering up the existence and how wide-spread the virus was.
Why not? Don't allow ships coming from China to enter the harbour, don't allow planes coming from China, either directly or indirectly, to land at your airports, and for most countries outside of the China region of Asia that would already create a quite effective containment.
And this is the Google Data Studio Visualization Dashboard:
https://datastudio.google.com/reporting/3ffd36c3-0272-4510-a...
And data is provided by official source from DXY.cn, http://3g.dxy.cn/newh5/view/pneumonia