Guest Post: Covid-19 Percentages and Exponentials

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.