Where are the recoveries?
All numbers below
are based on yesterday’s reported figures of total confirmed cases, total deaths
and total recoveries, published on Worldometers.info. I’m happy to send my
spreadsheet that calculates all of these to anyone who wants to check the
calculations, although they follow the assumptions described below.
I. Numbers based on total cases,
actual and projected
Total US confirmed
cases: 367,659
Increase in cases
since previous day: 30,818 (vs. 25,214 increase yesterday)
Percent increase
in cases since yesterday: 9% (vs. 8% yesterday)
Percent increase
in cases since 3 days previous: 32% (vs. 37% yesterday)
“Set in stone” US deaths* over course of
pandemic: 216,390 (based on 4% case mortality rate)
*This number assumes a) Total cases grow by
30% into the future (= yesterday’s 3-day growth rate in cases); b) We impose a
massive lockdown, with prohibition of all non-essential travel, today; c) New
cases drop to zero in 28 days, because of the lockdown, but they continue to
grow at the current projected rate up to the 28th day; d) testing is
widely available by the 28-day mark; and e) case mortality rate = 4%. To
consider a 6% mortality rate, multiply each projection by 1.5. For 8%, double
it. For comparison, Italy’s case mortality rate is currently 11.75%.
Projected as of April 14 (7 days from today):
These numbers answer the question: What would
happen if we wait seven days to totally lock down the US, based on the
assumptions below (which frankly are themselves wildly optimistic).
Total expected cases*: 774,747 (vs. 801,329 expected yesterday)
Total expected deaths set in stone* over
course of pandemic: 411,521 (vs. 589,040 expected yesterday)
* The expected cases and deaths set in stone numbers
assume a) Total cases grow by 32% into the future (= yesterday’s 3-day growth
rate in cases); b) We impose a massive lockdown, with prohibition of all non-essential
travel, on April 14; c) New cases drop to zero 28 days later, because of the
lockdown, but they continue to grow at the current projected rate up to the 28th
day; d) Testing is widely available by the
28-day mark; and e) case mortality rate = 4%. To consider a 6% mortality rate,
multiply each projection by 1.5. For 8%, double it. For comparison, Italy’s
case mortality rate is currently
Projected as of April 21 (14 days from today):
These numbers answer the question: What would
happen if we wait 14 days to totally lock down the US, based on the assumptions
below (which frankly are themselves very optimistic)?
Total expected cases*: 1,473,380 (vs. 1,625,701 projected yesterday)
Total deaths set in stone* over course of pandemic:
1,248,242 (vs. 802,265 projected
yesterday)
* The expected cases and deaths set in stone
numbers assume a) Total cases grow by 32% into the future (= yesterday’s 3-day
growth rate in cases); b) We impose a massive lockdown, with prohibition of all
non-essential travel, on April 21; c) New cases drop to zero in 28 days,
because of the lockdown, but they continue to grow at the current projected
rate up to the 28th day;; d) Testing is widely available by the
28-day mark; and e) case mortality rate = 4%. To consider a 6% mortality rate,
multiply each projection by 1.5. For 8%, double it. For comparison, Italy’s
case mortality rate is currently 11.75%.
Date on which 500,000 deaths will be set
in stone: April 17
Date on which 1 million total pandemic
deaths will be set in stone: April 24
Number of deaths set in stone on April
30: 1,845,184 (vs. 3,603,124 estimated yesterday)
II. Numbers based on total deaths, reported
and projected
Total US deaths as of yesterday: 10,943
Increase in deaths since previous day: 1,323
(vs. 1,625 yesterday)
Percent increase in deaths since previous day: 14%
(vs. 14% yesterday)
* Projected deaths = previous day’s new
deaths number, grown by that day’s 3-day percentage growth rate. Note this is
calculated completely differently from the deaths set in stone, which refers to
projected deaths over the entire pandemic, and is calculated by multiplying
expected cases by the mortality rate
Date on which the number of new deaths on
that day will probably exceed the toll of Sept. 11: April 13
Projected*
number of actual deaths on 4/14 alone: 3,780
Projected*
number of actual deaths on 4/21 alone: 9,395
Number of deaths on that day on
April 30: 30,455
III.
Reported case mortality rate so far in the pandemic in the US:
These
numbers are also unaffected by the error I made.
Total
Recoveries in US as of yesterday: 19,814
Total
Deaths as of yesterday: 10,943
Deaths
so far as percentage of closed cases (=deaths + recoveries): 36% Let’s
be clear. This means that, of all the coronavirus cases that have been closed
so far in the US, 36% of them have resulted in death (compare that to the 4%
mortality rate I’ve been using to calculate total pandemic deaths, based on total
cases). Of course, this number will come down as time goes on and more cases
are closed in which the victim recovered. But it’s only come down by about 4
percentage points since Worldometers started publishing the recovery rate on
March 26, and on about half the days, it’s gone up; there is still no sign of a
downward trend. I’d say it’s much more likely my 4% mortality rate will turn
out to be too low, after the pandemic’s over and all of the bodies have been
counted, than it will be too high.
One observation, before I get to my main
topic for today. Yesterday, the three-day percent changes of both total cases
and total deaths fell – these are the two actual numbers that I derive all of
my projections from. And you can see that a lot of my projections fell
significantly. For example, my projection of total deaths on April 30 alone
fell from about 80,000 to 30,000. This is good news, right? It sure is – if you
consider a one-week postponement of Armageddon to me good news. But the day on
which we’ll pass one million set in stone deaths is about five days after the
day I projected yesterday, and the difference for further milestones like two
million is also less than a week.
That’s the problem with exponential growth.
You have to stop it cold; even a fairly small rate of growth will still result
in huge absolute increases later on. So how can we stop the coronavirus cold?
Through a complete lockdown for at least one month and probably more, along
with a massive rollout of testing (where we can test every citizen multiple
times). Anything less than that will never solve the problem. End of today’s
sermon.
I wish to focus today on reported recoveries
from Covid-19 in the US. Worldometers just started publishing this number on
March 26; it sums up recoveries reported by different jurisdictions (I presume
states). I use it to calculate the “Deaths so far as percentage of closed cases”
number shown above. The formula is very simple: Add total recoveries to total
deaths to get total closed cases, then divide total deaths by total cases.
This number answers the question “Of all the
people who have gotten sick with Covid-19 so far in the US, what percentage
have died?” And here’s the problem: On March 26, that number was 41%. I (and my
friend Kevin Perry, who has discussed a lot of these issues with me) thought
this would surely come down.
There are good reasons why it has to come
down. Perhaps the biggest is that, to confirm that someone is free of the
virus, the hospital has to administer two tests. But with tests being in very
short supply (and the wait time for a reading varying from 1-2 weeks), many hospitals
are very reluctant to use up two tests confirming something they can see
clearly just from looking at the patient: they have recovered. Also, in case
you haven’t read the news, a lot of hospitals are very busy now. To devote
precious time to just certifying that a patient – who has probably already gone
home – is virus free seems almost criminal, given there are people in acute
need who probably could use all the attention they can give them.
But the problem is, the number hasn’t come
down significantly. Since March 29, it’s been fluctuating in the 35-37% range
up and down (today it’s up). I’m still sure it will come down a lot sooner or
later, but if you look at other countries, they seem to be in the same
situation. Italy’s rate is 42%. France’s is 34%. Spain is lower at 24%, but
that’s very high. South Korea is at 3%, but of course they had widespread
testing available very early and have managed the epidemic extremely well.
I’m using a rate of 4% as the case mortality
rate for the US, and I’ve taken a fair amount of heat from people who say that’s
too high. But when I compare it to 36% and consider that number has barely
changed in two weeks, I’m wondering whether it should be higher than that.
The mortality rate is included in my
calculation of the “set in stone” death numbers, not the daily deaths numbers,
which are generated by growing the current number by the 3-day rate of change. My
methodology for calculating the set in stone numbers is described above, but
the key part is that the mortality rate is multiplied by the total number of
cases 28 days after the measurement date (i.e., today’s set in stone number of
216,390 equals the total expected cases on May 4 times .04). So if the
mortality rate doubles to 8%, then every set in stone deaths number above needs
to be doubled. If it goes to 6%, those numbers need to be multiplied by 1.5.
And if you consider a 24% rate like Spain’s, you need to multiply each number
by six, which would mean that more than 1.2 pandemic deaths are already set in
stone in the US.
What do I believe the real rate will turn
out to be, once the pandemic’s over and we presumably know all of the deaths (deaths
are likely to be underestimated for various reasons, but nothing like the
degree to which cases are surely underestimated now)? I don’t know. But I do
know that the most worrisome consideration in all of the projections I’m making
is this one.
BTW, I put up a post
last week that mentioned in the title there were three “windows” into total
pandemic deaths, but one was too horrifying to even discuss. Well, this is it.
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