Yesterday’s numbers (from Worldometers, as
of about 7 PM EDT March 30)
Total US confirmed cases: 164,435
Increase in cases since previous day: 21,689
(vs. 18,965 increase yesterday)
Percent increase in cases since yesterday: 15%
(vs. 15% yesterday)
Percent increase in cases since 3 days previous: 33% (vs. 37% yesterday)
Total US deaths as of yesterday: 3,175
Increase in deaths since previous day: 686
(vs. 260 yesterday)
Percent increase in deaths since previous day: 28% (vs. 12% yesterday)
Expected* US deaths over course of
pandemic: 85,749 (based on 4% case
mortality rate)
*This number assumes a) Total cases
grow by 33% into the future (= yesterday’s 3-day growth rate in cases); b) New
cases drop to zero on April 28, because of the lockdown; and c) 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%.
Projected as of April 7 (7 days from today):
Total expected* cases: 335,830
Total deaths set in stone** over course of
pandemic: 201,499
*Expected cases assumes a) Total
cases grow by 33% into the future (= yesterday’s 3-day growth rate in cases);
b) we wait until April 7 to impose a total lockdown; c) New cases drop to zero
on May 5, because of the lockdown
** Deaths set in stone = expected
cases X case mortality rate of 4%. To consider a 6% mortality rate, multiply
the figure by 1.5. For 8%, double it. For comparison, Italy’s case mortality
rate is currently 11%.
Projected*** number of actual deaths on
4/7 alone: 1,700
*** Projected deaths = previous day’s
death number, grown by the 3-day percentage growth rate. Note this is
calculated completely differently from the deaths set in stone.
Projected as of April 14 (14 days from today):
Total expected* cases: 503,157
Total deaths set in stone** over course of pandemic:
356,852
*Expected cases assumes a) Total
cases grow by 33% into the future (= yesterday’s 3-day growth rate in cases);
b) we wait until April 14 to impose a total lockdown; c) New cases drop to zero
on May 12, because of the lockdown
** Deaths set in stone = expected
cases X case mortality rate of 4%. To consider a 6% mortality rate, multiply
the figure by 1.5. For 8%, double it. For comparison, Italy’s case mortality
rate is currently 11%.
Projected*** number of deaths on 4/14
alone: 15,687 (equal
to about five times total deaths on 9/11. And this is the reported deaths in a single
day)
*** Projected deaths = previous day’s
death number, grown by the 3-day percentage growth rate.
Reported
death rate so far in the pandemic in the US:
Total
Recoveries in US as of yesterday (3/29): 5,211
Total
Deaths as of yesterday: 2,489
Deaths
so far as percentage of closed cases (=deaths + recoveries): 38%
Date on which 100,000
deaths will be set in stone: April 1
Date on which
500,000 deaths will be set in stone: April 18
Date on which 1
million deaths will be set in stone: April 25
“Set in stone” means that on that date, a total lockdown will
be put in place. It will be 100% effective (0 new cases) 28 days later.
I didn’t make any changes in how I’m doing
calculations today, but I tried to make the results in the tables above a lot
more understandable, and to provide the complete explanation of each number
right below it. My goal, of course, isn’t to provide some dry statistics for
scholars to review later on, but to try to project what will happen in a way
that’s totally transparent. This compares with what you read in the newspapers,
which is always what one expert or another says will happen. You don’t know how
each expert projected their numbers (unless you’re prepared to read some
lengthy paper somewhere, which almost nobody in the general public will do),
and you don’t know why one expert’s numbers differ from another’s, or even what
precisely the numbers mean.
I’m not developing estimates using anything
but simple arithmetic: no modeling of the virus spread, etc. – I can’t do that,
and frankly I don’t know how well the epidemiologists can either, since this is
such a different situation from before. I’m just trying to explain how I
project the numbers and what precisely my terms mean. If you don’t agree with the
numbers (and I’m sure many if not most of you don’t), then please let me know
your concern, so I can figure out if I’m doing something wrong. Unfortunately,
the few people I’ve heard from with concerns have usually just said they’re
tired of seeing my gloomy posts – they’re inundated with information and don’t
know what to think (which sometimes – but not always - means they’ve made up
their minds, so they don’t want to see any more information).
I have developed a standard answer for these
people: If you don’t want to read my posts on the pandemic, you have my
permission to delete them from your inbox (as if you needed it). If you’re
worried you then won’t know about new NERC CIP posts that I put up, you’ll have
to check the blog every day to see if one of those has been posted (of course,
this applies to Tom Alrich’s Blog, not The Pandemic Blog. I will only post pandemic
posts on the latter). But I’m going to write about what I think is important
each day. And frankly, I think any human being in the United States should be
paying a lot of attention to what’s going on with the pandemic. Even if you’re
not infected now, I’m sure it’s already affected your livelihood; those effects
alone will continue to increase.
My projected numbers are based on three
numbers that I get every day from a site called Worldometers (who gets their
numbers from various sources, including the CDC, Johns Hopkins, etc. The
numbers are a) total cases in the US, b) total Covid-19 deaths in the US, and c)
recoveries in the US. I just project out the first two. However, even though I
use the same calculation to project them out (a 3-day growth rate), they have
very different significance for what’s most important in the pandemic – the number
of deaths (and if this were a pandemic caused by a disease that is unlikely to
kill many people, neither I nor most others who write about Covid-19 would be
spending the time to do this).
I’m projecting future deaths in two very
different ways. The first way I project deaths is to take the total cases and
multiply that by an estimated case mortality rate. I project cases by growing
the number three days ago by the most recent 3-day growth rate. Of course, that’s
accurate when projecting out a day or two, but it loses accuracy rapidly as we
go forward. Since there’s no clear trend to the case numbers (recently the rate
of increase has been falling, but there’s no assurance that will continue – see
below), the best one can do is update the growth rate daily, so it always
includes yesterday’s number.
The mortality rate I’m using now is 4%. This
compares with 11% for Italy, and 6-8% for France and Spain, as well as 1.4% for
South Korea. I discussed the mortality rate in yesterday’s post. I frankly
think that 4% might end up being low, once the pandemic is over and all of the
counting is done.
However, there is a data point that can
provide some evidence for the actual mortality rate. That is the ratio of total
deaths to closed cases, which I report above as well. Closed cases equals total
deaths so far plus total recoveries. At the end of the pandemic, when all cases
are closed one way or the other, this will provide the final mortality rate,
and there will be no need to project it anymore. That is, unless you think the
US government is fudging one or the other number, or both. China now is being
accused of under-reporting both cases and deaths, so I’m not trusting the
numbers from them in the future, unless they can clean up the doubts.
So what is the ratio of deaths to closed
cases today? It’s 38%. Of course, if this were to end up being the
actual mortality rate, it would mean that many tens of millions of Americans
would die in the pandemic. Fortunately, this ratio will certainly come down, as
more recoveries are listed. But this is why I currently believe the mortality
rate will end up being no less than 4%, and very possibly more.
But let’s focus on the case number. How
accurate is that? It’s almost certainly way low. The Imperial College of London
(whose study was used to justify the administration’s social distancing rules a
few weeks ago) estimated the actual cases are between five and ten times that
number. Why is this the case? Of course, it’s because of the woefully
inadequate level of testing, which continues to be woefully inadequate.
Moreover, testing is likely to continue
to be woefully inadequate, since the president said two days ago, on a call
with the governors (who were pointing out that they need more test kits) that
he hadn’t heard there weren’t enough kits. This is probably a true statement,
since it’s likely that the limited set of news sources he listens to isn’t
talking about this problem. However, those of us who have to live in the real
world hear every day about a) people who clearly are sick, who can’t even be
tested, or b) people who finally get tested, but have to wait up to two weeks
to get their results, at which point the results are moot – either the person
has gotten over the disease or they’ve died. And even though new kits are
becoming rapidly available, the number of tests a hospital can do with each kit
depends on their having adequate supplies of the cotton swabs required to get
the sample, as well as the chemical reagents needed to conduct the tests – and these
are in increasingly short supply.
The bottom line is that the number of actual
Covid-19 cases in the US is likely to be many times the reported cases for a
long time, even if it ever catches up. And since there’s no good way to
determine where in the range of 5-10 times the multiplier is now, and more
importantly since it’s very likely that the multiplier itself is going up, as the
people with unreported cases infect others, I’m just going to stick with projecting
out the reported number. And I’ll continue to estimate total deaths over the course
of the pandemic based on the reported numbers, as described at the beginning of
this post.
But this means that the reported case number
is a good representation of one thing only: the availability of tests.
If the number of tests available were to double tomorrow, the reported cases
would almost certainly double – on top of the normal rate of increase due to an
increasing number of total cases. So the projections I’m making are almost
certainly going to continue to increase for a long time. The 3-day growth rate that I’m using to
project out has varied between 115% and 33%. 33% is the most recent rate, so I’m
using that in my projections, but as I said there’s no trend to that rate – it’s
already gone over 100% twice during March.
But you have to remember that the number of
cases is more than doubling every three days, even at the 33% rate. This is why
the 100 cases reported at the beginning of March had grown to 164,000
yesterday, which in case you have the courage to look at it, means cases have
increased 1,639 percent in 30 days. If we project that out over the next
month, that means total cases will be 2.7 million at the end of April. And not
surprisingly, that’s very close to the 2.8 million I’m projecting, since both
numbers are based on the same three-day growth rate. This is why I’m projecting
1.7 million deaths over the whole pandemic, if the current 33% 3-day growth
rate continues through April (at which point a total lockdown is put in place).
And since the number of actual cases is some multiple of reported cases, if
anything both of these April 30 numbers will be too low, not too high.
Of course, all of this comes from projecting
out total cases. What about projecting total deaths, which I’m projecting
independently? Those are calculated by growing the reported increase in deaths
3 days ago by the most recent 3-day growth rate, which as of today is 87% - and
by the way, this rate has been going down since March 17, when it was 117%
(where’s the luck of the Irish, anyway? Now that we need it most!).
Projecting the 87% rate through April 30
yields 2,183,000 total reported
deaths as of that day – this isn’t an estimate of total deaths over the
pandemic, as the other number is. So this is in effect hugely bigger than the
1.7 million figure estimated above, since there will be a lot more deaths
coming, certainly in the millions.
Yet I’m sure many of you won’t believe the
1.7 million figure (which I also find unbelievable). Great, where did I go
wrong? I think many of you will point out that there’s a lot more social
distancing going on now, and that has to affect it. It certainly will, but
remember that’s been going on for about 3 weeks already, and the case growth
rate has already fallen significantly; it almost certainly has somewhat further to fall. I certainly hope that
continues – but then you have the opposite consideration, which is that the
reported case rate is a fraction of the actual rate, and as testing ramps up,
the number of new reported cases will ramp up as well. Which will win out? I
don’t know, of course.
But there is one thing I do know: At
the end of the pandemic, the two numbers will end up at the same point. Whether
it will be closer to the number estimated based on cases or the number based on
reported deaths so far isn’t clear, of course. However, the fact that the
actual cases is a multiple of the reported ones only affects the reported case
number. The actual deaths depend on the actual cases – people don’t die only if
their case has been reported earlier. So at the moment, I have to say the final
toll for the pandemic will be well above 1.7 million (perhaps the 2.2 million
high estimate of the Imperial College).
Unless, of course, a total lockdown is
imposed very soon – certainly before April 30 (of course, my 1.7 million projection
for the total pandemic, based on cases, assumes there will be a total lockdown
on that day). And it will be, too – although some dead
wood will almost certainly need to be cleared out before this can happen.
Why am I optimistic about this? Two words: exponential growth. On April
15, there will probably be more than 100,000 reported deaths. If that
doesn’t get somebody’s attention, God help us. Probably nothing will.
Comments
and questions are welcome. You can reach me at tom@tomalrich.com.
