Mon Mar 16th, 2020 at 12:52:57 AM EST
This diary was inspired by Frank's "Corona Virus gets Real' diary and Number 6's "Flattening the Cruve" comment.
Using figures from Wiki for numbers of infections reported by states it appears that the doubling rate is a little more than two days. As of March 13 there had been 2,160 cases reported by US states. Rounding down to 2000 for that date and using two days as the doubling time interval, by March 31 there should be over 1,024,000 reported cases. By April 18 at a two day doubling interval 262,144,000 cases, or ~ 80% of the population could have been infected.
The cases by March 31 are unlikely to be affected by new 'social isolation' measures, as the incubation period is as much as 14 days, and most of these future patients are already infected. And these numbers are surely an undercount, as they are restricted to only those cases that have come to the attention of the medical profession and we rounded the first number down to 2000 from 2,160 for ease of presentation.
Continuing with this sequence through April, but assuming that on April 1 the social distancing has increased to doubling time to four days, so there are seven doubling times until April 28, when the number of infections are projected to be 131,072,000 - over a third of the US population.
Frontpaged - Frank Schnittger
Continuing at a four day rate for one more doubling, by May 2 there would be 262,144,000 infected. But at this point we are at ~ 80% of the US population and the model, hopefully, has broken down, as the infection rate will run into a limitation of available hosts. Some will have natural immunity, some will just be too remote to be affected and a lot of the cases will have been mild with the victim having acquired some immunity.
To assess impact let us take the March 31 date and value of 1,024,000 persons infected. If 10 % require intensive care that is 102,400 patients - greater than the total number of critical care beds in the USA. And most of those critical care beds are already in use on any given day. Our hospitals are certainly NOT oversized. So triage will have been implemented probably around a week earlier - say by March 25 - when the number of patients equaled 128,000.
Here is the sequence I used: 2,000, 4,000, 8,000, 16,000, 32,000, 64,000, 128,000, 256,000, 512,000, 1,024,000 etc. The start date used is March 13, 2020. The doubling rate used was 48 hours or two days. This gives one million twenty four thousand cases by March 31.
Let us see what happens with a different assumption abut doubling time. With the urgent action we are starting to see from governments let us assume that aggressive social distancing increases the doubling time to four days starting March 21 when there are 32,000 cases. On 3-25 there will be 64,000, on 3-29 there will be 128,000, on 4-2 256,000, on 4-6 512,000 and on 4-10 1,024,000 instead of reaching that number by March 31.
Now it takes until Mar-25 to reach 64,000 and it takes until April 18 or May-12, depending on assumptions, to reach 262,144,000 or ~ 80% of the population instead of reaching that number by April 18 or May-2. Ten to fourteen whole days for me to contemplate my possible demise, given I have kidney function reduced to 40% and am missing the right lower lobe of my lungs. If I get the disease I had better get a mild case, as at age 77 I would be unlikely to be selected for intensive care.
I might have a one in five chance of surviving or not even getting the disease, as I live in a town of ~ 12,500 and we are isolated by the Ozarks from larger cities. But then there are those who regularly travel to larger cities, including truck drivers who deliver the food and other supplies we consume. Oh brave new global economy wherein there are such features.