Vox, 4193 is from the gis site ,
https://gisanddata.maps.arcgis.com/apps/opsdashboard/index.html#/bda7594740fd40299423467b48e9ecf6
Sam, Do you propose numbers are higher?
If shelter in place is recommended how do we know the number infected ? If you are sick enough to go to the hospital in Wuhan you represent the 4193 number I assume.
Yes Kiwi now 4474 on the gis site also.
I wish I knew Bruce. I have the same access to information all of you have.
One seemingly good reference from the first public modeling of the spread concluded that the confirmed disease numbers represent 5.1% of the total infected population. If that is right it suggests that there are now 90,000 infected.
This is plausible. Looking at the data over this past week, the totals of those confirmed infected and those who died suggested that the disease was spreading at a rate of 1.31 to 1.42 fold each day (my naive estimates). The report also suggested an average 6.4 day incubation period. That has not much changed. The range has expanded to 2-14 days. The same report suggested an R0 of about 4.
A day to day growth of 1.31 fold with a 6.4 day incubation period would result in an R0 estimate of about 5.6. That's not far off. A 1.31 fold daily increase in the total infected combined with a 5 day average incubation period would result in an R0 estimate of about 3.9. Etc...
What each of these suggest is that the uncounted infected pool is about 5 times the confirmed count, rather than the 19.6 fold that a 5.1% counting efficiency might suggest. But, if we count the suspect cases, we are only off by a factor of 2.
With exponential problems like this, combined with uncertain estimates of the real averages and distributions, and with unknown actual infection levels compared to confirmed counts, this is all about what we can expect.
One of the other confusion factors is the severity of infection and symptoms versus health, age, gender and other factors. This disease seems to (as expected) principally effect those over ~age 55 and male (70%). If young women in particular are less symptomatic, they may be dramatically under counted, and, they may also contribute to a greater degree to silent disease spread.
Then again, those seemingly important parameters may be to greater or lesser degrees be societal artifacts.
My wild ass guess is that the Chinese have done a great job in counting, that they are at or above maximum capacity in Wuhan, and that the societal and disease factors combined with the math problems of dealing with a rapidly and exponentially increasing disease spread put the real infected population at between 10 and 20 times the confirmed count but that is purely a wild ass guess. The professionals can do much better using modeling to try to estimate all of the various parameters involved. If they are above capacity in Wuhan as the center of the outbreak, then the counts may become much less representative of reality. On the other hand, the near cessation of movement in Wuhan should independently have greatly reduced the R0. But it doesn't appear to have done so.
I think the point I would emphasize is that whatever the reality is that these seemingly large ratios are inherent to the large replication factors and incubation period. We should expect them to be as they are. We should NOT take comfort in the seemingly small numbers of those confirmed infected or killed. And we should NOT compare these to seasonal flu or other diseases. Doing so will be misleading and get us in trouble.
I would also suggest that if there is (as there appears to be) a several day to week long period where people are infected and can transmit the disease, that controlling the outbreak will be extremely difficult. It will most likely cause reasonable professionals and politicians to consistently underestimate the spread of the disease and the severity of the outbreak. It is also likely to cause simple screening such as temperature monitoring at points of entry to be largely ineffective. And that may cause false confidence in the effectiveness of control efforts.
The hazard of that is the potential for the disease to spread globally and to result ultimately in over 100 million dead, and possibly over half a billion. Those are horrifying possibilities.
Combine too the difficulty and impacts on privacy, liberties, ... of taking actions that will stop such a rapidly expanding plague. Then compound that with the huge array of financial and market impacts on our now hugely interconnected world.
Conversely, consider the global tragedy and impacts of sickening most of the people on Earth and killing several hundred million if we act too slowly and wrongly.
Either way the consequences look to be enormous both for those alive today, and for everyone everywhere as we move into a radically different future. If these disease is one of the period global pandemics that wipe out up to 10% or more of the population in a matter of a few months, it is inevitable that that will create truly enormous societal impacts. And these are unlikely to be transient impacts. If control fails, this will be a turning point, just as the Black Death and other plagues were. And we need only look to them to get some idea of the scope, scale and severity of the societal impacts to come.
Also, if this plague progresses globally and unchecked, with the current R0 and incubation periods, it will likely all play out by about May. That is a nearly unimaginable scale of impact over an incredibly short period.
Most of the decision makers experience is based on completely different conditions. This is likely to lead them to fail to act either quickly or decisively enough. China has already done far more far faster than could ever have been expected. And it does not appear to have been nearly enough. In western societies, the structure of the societies will not allow anything close to their response. Perhaps the best that can be hoped for is for individual action and response to make the difference. History of human behavior does not make that a promising route.
Sam
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