Posted on 09/15/2014 2:50:13 PM PDT by scouter
My User Name on Free Republic is Scouter. I have been a member of Free Republic for 14 years. I don't write many vanity posts, but I consider this one to be very important. I had been working on this post for several days, and I was planning to post it tomorrow. But the Drudge Report headline CDC: PREPARE FOR EBOLA has moved up my timeline.
I have developed a model for making future projections of the number of Ebola cases. I have undertaken this project for several reasons. First, out of simple professional curiosity. Second, I believe the time has come to be concerned and to prepare for the possibility that the Ebola epidemic could spread to other countries, including the United States. And third, my daughter will soon begin working as a nurse in a major Pediatric Intensive Care Unit, which will likely see some of the first Ebola cases in the United States, should it make an appearance here.
I am not an epidemiologist, and I have no inside knowledge about the current Ebola epidemic. But I have spent the last 26 years of my career applying computers to the practice of medicine and to medical data. I hold a Master's Degree in Medical Informatics from a major university known for their expertise in that field. I currently work in that field at a large, famous, metropolitan teaching hospital. I am remaining anonymous only because I don't want my employer to be held responsible for this post in any way. It is my work exclusively, and I am responsible for any information or projections it makes.
The numbers produced by this model are "projections", not "predictions". That is to say, I do not predict that there will be x number of Ebola cases on any given future date. Rather, I "project" into the future, assuming a constant Daily Transmission Rate (DTR), based on past data. Any number of factors can influence future DTR, in either a positive (bad) direction, or in a negative (good) direction. There is no way to know how these factors will actually play out. If there were, then we would be able to make actual preditions. As it is, we are left only with the ability to say "If Ebola continues to spread at the same rate it has been spreading for the past x number of days (or months), then this is approximately how many people who will have contracted the disease as of this particular date in the future." Not ideal, for sure, but still quite useful to understand the seriousness of the situation.
I have validated the model based on actual data by calculating the DTR for various periods of time and comparing the model's projections with what actually happened in subsequent periods. This is the same concept that is being used by epidemiologists at CDC and elsewhere. It is a valid method, within the constraints I have mentioned above. My model has been completely in line with projections I have seen quoted in the mainstream news. It works quite well. If anything, my model's projections are a bit more conservative than some projections you may have seen in the mainstream media. I just take them out further than you have seen in other places.
That being said, the following projections are based on the Daily Transmission Rate (DTR) from June 1 through September 10, the last date for which I have data. The DTR has remained relatively stable over that period. To be conservative I assumed that the reported number of cases represent the true size of the epidemic. However, the WHO, CDC, Medicins Sans Frontieres, and Samaritan's Purse all agree that the number of reported cases represents only 25% to 50% of the true number of cases. I have decided to be conservative in the numbers published below, but the model allows you to adjust this percentage.
As you review these projections, remember to pray for all those who are currently affected by this terrible disease, those who have it, those who will die, and their families. Do not forget that these are real people with eternal souls, who will either go to heaven or to hell, depending on whether or not they die in friendship with God. Pray, too, for an end to this epidemic. Do not underestimate the power of prayer!
The following projections assume that the currently reported cases represent 100% of the true epidemic size. In other words, that there are no cases that were missed by the epidemiologists. We know this not to be true, so we know that the "best case" is something worse than this, assuming the Daily Transmission Rate remains stable.
Scouter Ebola Projection Model Version 1.0 - Ebola Case Projections
*********************************************************
Projection Parameters
*********************************************************
Start Date: 6/1/2014
End Date: 9/10/2014
Reported cases represent 100% of the true epidemic size
Daily Transmission Rate (DTR): 1.00422415489918
*********************************************************
Weekly for the Next 8 Weeks
Date Cases Deaths Daily New Cases Daily New Deaths
========== ==================== ==================== ==================== ====================
09/10/2014 4,845 2,376 171 84
09/17/2014 6,227 3,054 219 108
09/24/2014 8,003 3,925 282 138
10/01/2014 10,285 5,044 362 178
10/08/2014 13,218 6,482 465 228
10/15/2014 16,988 8,331 598 293
10/22/2014 21,833 10,707 769 377
10/29/2014 28,060 13,761 988 485
End of Month for the Next Year from the End Date
Date Cases Deaths Daily New Cases Daily New Deaths
========== ==================== ==================== ==================== ====================
09/30/2014 9,923 4,866 349 171
10/31/2014 30,146 14,783 1,061 521
11/30/2014 88,357 43,331 3,111 1,526
12/31/2014 268,427 131,637 9,451 4,635
01/31/2015 815,475 399,911 28,713 14,081
02/28/2015 2,224,815 1,091,055 78,336 38,416
03/31/2015 6,758,941 3,314,601 237,983 116,707
04/30/2015 19,810,535 9,715,135 697,531 342,071
05/31/2015 60,183,993 29,514,379 2,119,084 1,039,204
06/30/2015 176,399,989 86,506,991 6,211,061 3,045,920
07/31/2015 535,899,508 262,806,446 18,869,075 9,253,441
08/31/2015 1,628,051,594 798,400,534 57,323,860 28,111,763
09/10/2015 2,329,918,242 1,142,597,677 82,036,655 40,230,979
The following projections assume that the currently reported cases represent 75% of the true epidemic size. Remember that Medicins Sans Frontieres, Samaritan's Purse, the CDC, and WHO all agree that the number of reported cases already vastly underestimates the true size of the epidemic. They say by a factor of 2 to 4.
Scouter Ebola Projection Model Version 1.0 - Ebola Case Projections
*********************************************************
Projection Parameters
*********************************************************
Start Date: 6/1/2014
End Date: 9/10/2014
Reported cases represent 75% of the true epidemic size
Daily Transmission Rate (DTR): 1.00422415489918
*********************************************************
Weekly for the Next 8 Weeks
Date Cases Deaths Daily New Cases Daily New Deaths
========== ==================== ==================== ==================== ====================
09/10/2014 6,460 2,376 235 115
09/17/2014 8,373 4,106 305 149
09/24/2014 10,853 5,322 395 194
10/01/2014 14,068 6,899 512 251
10/08/2014 18,234 8,942 663 325
10/15/2014 23,635 11,591 860 422
10/22/2014 30,635 15,024 1,115 547
10/29/2014 39,709 19,473 1,445 708
End of Month for the Next Year from the End Date
Date Cases Deaths Daily New Cases Daily New Deaths
========== ==================== ==================== ==================== ====================
09/30/2014 13,556 6,648 493 242
10/31/2014 42,764 20,972 1,556 763
11/30/2014 129,996 63,750 4,729 2,319
12/31/2014 410,085 201,107 14,920 7,317
01/31/2015 1,293,657 634,413 47,066 23,081
02/28/2015 3,651,570 1,790,739 132,851 65,150
03/31/2015 11,519,271 5,649,079 419,092 205,524
04/30/2015 35,016,714 17,172,283 1,273,972 624,759
05/31/2015 110,464,001 54,171,820 4,018,881 1,970,869
06/30/2015 335,792,614 164,673,529 12,216,744 5,991,122
07/31/2015 1,059,294,023 519,480,413 38,539,038 18,899,640
08/31/2015 3,341,657,268 1,638,757,001 121,575,553 59,620,953
09/10/2015 4,840,743,028 2,373,912,370 176,115,013 86,367,239
Obviously, there are many factors that will affect these projections. Rather, this model simply projects the number of cases and fatalities based on the current Daily Transmission Rate (DTR), which has been stable for about 3 months. Consider the following other factors that are likely to change the DTR (either for good or for bad) as we move forward from today:
While the numbers quoted above are grim, they do not yet represent fact. Do not panic, but do not be complacent, either. Any preparations you make to "shelter in place" will serve you well for other contingencies, too.
On the other hand, epidemiologists are already saying that the number of cases is already doubling every two weeks. That means that the numbers I've posted above are actually quite conservative.
This model is contained within a macro-enabled Microsoft Excel 2010 spreadsheet (i.e., a .xlsm file). I would be willing to share it with other Freepers if someone can provide a place to post it for download and can tell me how to sanitize my name from it (again, I don't want my employer to be in any way held accountable for this).
I wonder how many Chinese and Arabs fly to and from Africa?
Frightening.
A while ago, I put “30,000 dead by Jan 1 2015” on my wall at work. People thought I was crazy. I guess it turns out I’m an optimist.
I think that just as malaria has a worse DTR in some areas than others, Ebola is kinda the same way. Only with Malaria it is natural environment while with Ebola it’s the “civilization” environment. Just as women tend to be a natural firebreak to Aids (unless engaging in anal sex), civilization is a natural firebreak to Ebola.
Am I reading this correctly? You are projecting close to 5 Billion cases by the end of the next 12 months?
Prayers.
Great analysis...1 to 2 billion dead in a year based on current information is that correct?
Wow.......
Those are staggering numbers. I am praying...
You could place the spreadsheet on dropbox.com. It’s no charge. After upload there’s an option to click to get a url that you can give to others so that they do not have to signup with dropbox, makes sharing ez.
Political factors, such as the a mandated quarantine, bans on travel to affected areas, closing of borders/airports
Mutation of the virus which affect its ease of transmission or lethality
I think yours is high. A month ago when the spread rate was 5% increase per day, I was projecting 200,000 in 90 days. But the most recent week showed a spread rate of 3% which would put us at 69,000 by Dec 12th.
Basic formula that I’m using is:
Current Cases * (SpreadRate)^#DaysOut)
Still a very serious crisis. One that the WHO has been criminally negligent in responding to.
I think yours is high. A month ago when the spread rate was 5% increase per day, I was projecting 200,000 in 90 days. But the most recent week showed a spread rate of 3% which would put us at 69,000 by Dec 12th.
Basic formula that I’m using is:
Current Cases * (SpreadRate)^#DaysOut)
Still a very serious crisis. One that the WHO has been criminally negligent in responding to.
Only if the current Daily Transmission Rate holds that long and if the current reported numbers represent 75% of the true numbers. There are many factors that could increase (bad) or decrease (good) that rate.
In fact, I do not believe it will pan out that badly. There are many, many, things that will work together to lower the DTR. And a small change in the DTR can have a huge effect on the projections. But this is presented as a warning to those who are pooh-poohing the issue. The math doesn't lie.
And I'm glad that you picked up on the key word: projecting, not predicting.
Thanks for your summary. I appreciate the efforts.
Kind of a downer right before dinner though.
Thanks and Yikes!
The only other thing I would consider are the non-Ebola increased death rate.
It is to be expected that caregivers will be hit hard, and early. Follow on deaths would skyrocket. For example: cancer patients, cardiac, and other first responder issues that would normally be treated.
I would guess that mortality rate will tick up another 5-10% above norm because of this.
Don't you remember the good old days when you would read about something like this every few months or so?
Now, it is on a daily basis.
Before long it will be hourly.
PING
Don’t forget possible intentional spread...
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