Guest Post: Covid-19 Percentages and Exponentials

NCS:

I sent out an update yesterday on the Covid19 outbreak, regarding an excellent article posted on ZeroHedge regarding the impact of this epidemic.  The author had done some analysis of the numbers of people affected, and what that meant in the context of the current US health care system.  Here is what I said about that-


https://www.zerohedge.com/health/all-hospital-beds-us-will-be-filled-coronavirus-patients-about-may-8th-according-analysis

I hate it when I am right. Washington State, (and NY, and CA, and other places,) case counts are rapidly increasing, both from more testing and more infections.  Confirmed case counts now are just the tips of a whole field of icebergs we are just starting to be able to see.

The low number of confirmed cases in these presently united States is due to lack of testing, not lack of infections, and now that more testing is starting to be done the numbers of cases may be expected to rise significantly, right up to the limit of testing capability.  The reported case count will continue to be limited by testing as the real number of infections doubles every 4-7 days, possibly faster.

And here is the ugly thing.  Right now, with seasonal flu in full swing, HOSPITALS ARE ALREADY FULL.  At my hospital, we routinely have to wait for discharges for ill patients to get a bed.  Our census is 100%, the IP nurse is already swamped, and staff shortages are already an issue.  When this virus hits, (and there is no reason to think that the present rapid expansion in case numbers is going to slow down for at least several months,) we will have NO BEDS.  As staff infections increase, and they will, we will have fewer nurses to treat more patients, which is not sustainable.  Hospitals are going to close or go on bypass.  Surgeries, if any, are going to be restricted to emergency only.

The Life Center in King County is just the first of the horror shows we will see in long term care facilities.

Bottom line:

If you are not already prepared to treat your family members at home, you are behind the curve. Do not be that person.

Historian”

So, I got a reply from one person which said-
“CFR rate estimates aren’t 2%.  

 
 

https://news.yahoo.com/coronavirus-mortality-rate-1-percent-less-us-173432468.html

The implication apparently was that because the CFR was lower than that engineer’s estimate that the impact would be much less.  Here is my lengthy response to that:

Dear XXXXX:

If true, that would mostly be good news.  Hopefully it is, and the thesis makes sense, but CDC has no way to prove that this hypothesis is correct.  They cannot test enough to even verify that the clinical cases now in hospitals are infected, despite days of pleading for testing by the HCWs in the field.   CDC’s lack of testing is part of the problem we face, and you will understand my reluctance to interpret this latest from the Federales as anything but a bunch of happygas designed to blunt the understandable outrage from the public and the professionals both of whom they screwed.  (I was particularly impressed by the pronouncement that filter masks would not protect the public, but were needed for healthcare workers, who they would protect.)

The effects upon those who get severe versions of this disease will not be much different, and the data there are not in much doubt.  What that 1% number would mean is that the real percentage of severe cases is probably less, about 8-10 percent of the total, instead of around 16-20%, and that the mild/asymptomatic cases are ~90% instead of ~80% fo the total.  The bad news would be, if this is true, WRT Washington state for example, that the mild asymptomatic cases are twice as many, meaning that the disease has already spread faster and more quickly than expected. This will chop about a week or more off the estimate from that Zero Hedge article.  The other bad news is that those in the general population who are more likely to find themselves with severe cases are more likely to be exposed sooner to, and infected by, an asymptomatic case.

Another problem is that there are presently several clades of the virus, one family of which has mutated to be nastier and more aggressive, and as an RNA virus, this bug is unstable and liable to frequent change to better adapt to the host.  This is exacerbated by the propensity of immature genengineered virii to be unstable anyway. Worse, infection by the mild clade may not confer immunity from the nastier ones as has been reported in the literature.

Bottom line, it really does not matter whether the CFR is 1/2 of a percent, or 3.4%.  That is irrelevant.  The relevant piece is that with even a small fraction of the population infected, the health care system is going to be flattened, as the original ZeroHedge author stated.  As flat as a squirrel squashed by a semi. Let me show you what I mean- see spreadsheet attached

If only 20 percent of the people in your state get infected, and only 8% of those are severe cases then 360,000 people will get it, and  about 28,800 people will need hospital/ICU care ( isolation rooms, ventilators, O2, etc.) over about a 1-4 month, possibly longer, period.  Average stay for a severely ill Covid19 patient is probably two months, give or take. 1% CFR means about 3600 across the state will die, but that is not the problem. Real world is that the disease may come in one or more waves, and each wave of cases is likely to present as something like a normal bell-curve, with a fat tail.  It will start with just a few cases, as we’ve seen so far, but the count will grow exponentially at first, again as we’ve seen, then decrease after the peak.

On average, ICU beds typically are about 5%-10% of the total beds in a hospital at most.  The hospital I work at has 3 iso rooms in the ED and we have 4 ICU iso rooms,  and others throughout the hospital.  My hospital, which is 5 star ranked, is far above average; most hospitals nationally do not meet these standards.  Anyhow, your state has about 6000 licensed beds in the whole state,

https://www.ahd.com/states/

and if the census in your state is currently about the yearly national average,  that means that about 25% of these beds are vacant, or about 1500 beds statewide.  This time of year, however, most hospitals are running around 85% or more full.  (Right now my hospital’s census is 100% with around 15-20% of the cases serious flu patients on O2 and/or vents.) Of those 6000 beds, let’s assume that 10% of these are ICU beds, and 10% of those are iso rooms.  That optimistic estimate  means we have about 60 isolation ICU rooms in the your entire state with probably about another 200 isolation rooms without ICU capability. Locally, the tiny hospital in your community has 25 beds;  there are about another 150 beds within an hours drive of your home.  Those 175 beds serve a resident population around of around 100,000 people.

Anyway, lets say that this Monday we see 2 cases, later confirmed as Covid19, somewhere in your state, with severe symptoms. Right now, cases seem to double around every 4 days;  people seem to die about 2 weeks to 6 weeks from Covid19 infection;  there are a peak of early deaths from elderly patients with co-morbidities; the initially healthy patients with severe cases hang on longer. It seems to take longer for recovery;  I’d guesstimate that on average that takes 4 weeks, but there are plenty of folks still using o2 and respirators 2 months after being infected.

After about three weeks, your state will have run completely out of isolation rooms, even assuming there were no isolation patients already in them, and assuming all the cases are evenly distributed, with 254 patients presented.  By day 36, we will have overrun the 1500 beds available, with 2046 severe cases presented.  Some of the early cases will have died, and a few have recovered, but the hospitals will be over-run in just over a month, and probably around 5-10% of those will be doctors and nurses. By day 44, six weeks into the outbreak, 8000+ patients will have presented.

On Day 48, which will probably be the peak of our estimated 20% attack rate epidemic, about 16000+ cases will have presented, 41 will have died, and 116 have recovered. With only 6000 beds total statewide, and only 1500 at best available for Covid19 patients, the other 14,500 cases will not be in hospitals.

Now obviously, this is a very simple model.  You can change the assumptions WRT doubling time, etc., (which I have done) but all that does is slightly extend the time to overload.  The point is that it won’t take very long for a very infectious bug like this one to wreak havoc on the health care system in this country, just as it did in China.  And that does not take into account the need for PPE, now not being produced in China, as it was.  Every patient in isolation will require a minimum of 6 N95 masks per day per patient, more likely double that. If the average stay is 4 weeks, that is 168 masks per patient, more likely 300 plus, or 4.8 million N95s for all the infected in your state alone. If the average stay is longer, that number grows.  Even if we figure that only 6,000 people will be treated statewide in hospitals, that’s a bare minimum of 1 million needed. In your small state! The national stockpile, last I heard, was about 12 million masks;  the Federal Government has ordered 500 million, but that will take a long time to get- by the time we see those masks, this pandemic will probably have run its course in this country.

And that was an optimistic, best case scenario.  More likely, this epidemic will infect half to 3/4 of the people in these presently united States, because it will NOT be possible for everyone to isolate themselves for long enough to break the back of the epidemic and stop transmission.  Keep in mind that there could be another mutation, leading to another wave of infection, as happened with the H1N1 pandemic in 1918-1020.  In any case, my best estimate is this will be probably be worse than the 20% example above. A wise person will prepare for this.

With regard to all who serve the Light,
Historian

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About the Author: NC Scout

NC Scout is the nom de guerre of a former Infantry Scout and Sergeant in one of the Army’s best Reconnaissance Units. He has combat tours in both Iraq and Afghanistan. He teaches a series of courses focusing on small unit skills rarely if ever taught anywhere else in the prepping and survival field, including his RTO Course which focuses on small unit communications. In his free time he is an avid hunter, bushcrafter, writer, long range shooter, prepper, amateur radio operator and Libertarian activist. He can be contacted at [email protected] or via his blog at brushbeater.wordpress.com .

7 Comments

  1. Historian March 9, 2020 at 06:22

    I reread what I sent to NC Scout, and thought I’d clarify one point- The number of patients presenting at a hospital for treatment in the models I referenced are only the severely ill patients, those having significant respiratory issues. There will be others, perhaps up to 9 times as many, who have mild symptoms or possibly none they note at all.

    Exponential doubling in an epidemic is real, and I’m afraid that Americans will have a chance to see this in person. Soon.

  2. Veritas March 9, 2020 at 13:30

    This assumes non-stop doubling where we see China has already flatlined and actually has come down off its peak of active cases as over 62,000 people there have recovered and recoveries are offsetting daily new cases. This can be seen here at this excellent tracker by Johns Hopkins:
    https://www.arcgis.com/apps/opsdashboard/index.html#/bda7594740fd40299423467b48e9ecf6
    Also with some very rare cherry picked exceptions almost no one under the age of 60 without other chronic conditions has died and really the vast majority have been over 70. I’d hazard to guess some of the “but this one young Iranian athlete died” actually had some possibly even to them unknown underlying health issue. Also children seem to be essentially immune to it.
    At this point I am more concerned about the economic impacts to the world and US economy from this as well as people acting irrationally and fighting over toilet paper like in crazy video out of New Zealand.

  3. Historian March 10, 2020 at 05:17

    @ Veritas- At the start of a virgin field epidemic, where there is no immunity to infection, the case counts ramp up exponentially, as has been seen in South Korea, Italy, and is starting to be seen, (despite the lack of CDC testing) here in these presently united States. As the epidemic continues to grow, the doubling rate may change somewhat as social behaviour changes, reducing the rapidity of the spread, or as the virus mutates (as an RNA virus and a likely genengineered one, this has been shown to be quite mutable.) What the math says is that somewhere between the end of April or May, there will be no hospital care available, assuming that there is no miracle cure or major intervention by the various governments.

    As regards the death rate, it is early days yet and nobody really knows what the CFR will be. Data from China are not reliable, but keep in mind that the whistleblower doctor punished by the Central Committee for telling the truth about this outbreak in early December, Dr. Li Wenliang died in early February, aged 34, 2 months after he was infected. Let that sink in- it took him 2 months to die. What that says is that older people may die more quickly, but younger people die too. That is certainly the case in both Italy and South Korea, and will be likely the case here in these presently united States. But that is not the real problem.

    THE ISSUE IS NOT THE DEATH RATE. The issue is the number of people with severe illness who will be seeking (demanding!) care from facilities which will be completely overloaded and grossly understaffed.

  4. brad March 11, 2020 at 13:32

    There was a point made in the recent guest comment on covid19 that I have to point out as a slight problem. While I agree with the vast majority of the post… I don’t know if you are or have ever been married(this actually is relevant trust me), there is a look your spouse will give you that tells you somehow someway you’ve screwed up. My wife is a nurse and when I pointed out with great derision “(I was particularly impressed by the pronouncement that filter masks would not protect the public, but were needed for healthcare workers, who they would protect.)” I got THAT look. The thing, is if you use those n95 masks in a professional healthcare setting, a couple of times each year they have to be fitted and tested by spraying saccharine inside a hood… if you taste the sweet you start again. If you haven’t been fitted or have one of most styles of facial hair the darn thing won’t protect you. Since my wife has complained year in and year out for quite a while about what a P i t a the procedure of fitting is, she decided I haven’t been paying attention. So when it was said it wouldn’t work for the general public the guy wasn’t being a bald face liar(if fitted correctly it will fit bald faced liars). He just didn’t explain it very well

  5. Ronoid p. Hiero March 12, 2020 at 14:42

    Logical, responsible people will use the emergency rooms as designed. Illegals, and the gimme free stuff crowd will destroy the health care, and hospital system in short order.

  6. Historian March 14, 2020 at 06:15

    @brad

    Of course, you are correct WRT the need for fit testing, but the procedure is not difficult to learn and carry out; as noted the major problem is facial hair, and if I have to choose between exposure to a potentially fatal and VERY infectious disease, or having some protection, I’ll choose protection. The need for a proper fit for respiratory protection is not just for HCW; Any plant worker who uses a respirator understands the process and can carry it out. (A garbage bag and some finely powdered pink stuff ground up with a mortar and pestle can be made to work just fine, or one can pay for a ‘professional’ kit.) The brand (and shape) of mask, combined with the varying facial profiles of humans, can make getting a proper fit a challenge for some, but most masks fit most people with minimal adjustment. Testing is more about refresher training for HCW staff to ensure that they know how the mask their facility stocks needs to be put on.

    The way is which this was expressed by the bureaucrat involved, however, revealed the unconscious arrogance of the bureaucratic class, along the lines of “You unwashed civilians are too stupid to understand the need for proper fit testing, and I am too busy to explain it! No masks for you!”

    *That* attitude is part of the problem, not the solution.

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