
The New Coronavirus Growth Debate - imartin2k
https://www.bloomberg.com/opinion/articles/2020-03-03/how-fast-will-the-new-coronavirus-spread-two-sides-of-the-debate
======
whatshisface
Here's the real source of the debate:

"I look out the window and nobody has the virus. Nobody I know has the virus.
I don't know anybody who is talking about anybody they know that has the
virus. Virus? What virus? Oh, you mean the virus in China, the one sitting
next to the their weird government and the air pollution. I guess that could
make it harder for McDonalds to source their happy meal toys. Hey, did you
hear about the latest thing that happened in the primaries?"

It's weird, and it may even be psychologically impossible, to look out the
window at a sunny day and imagine that there's an explosion happening. You can
look at the numbers, but even then, can you really believe it on a deep
emotional level?

~~~
dwd
The problem is that statistically the confirmed number of cases is only 1 in 2
million in the US at the moment. Your chance of getting hit by lightning in
any one year is higher at 1 in 700k. So at this stage it is very hard to
comprehend.

It's when you consider the prediction that 40-70% of the adult population are
going to be infected if it's not halted that you have to take it seriously.
Noah Feldman while interviewing Harvard epidemiology professor Marc Lipsitch
who gave that figure admitted that it just didn't seem real that we are
looking at 1 million+ deaths in the US if that level of infection occurs. Very
sobering thought.

~~~
whatshisface
As far as policymakers are concerned, it's the 40-70% that needs to be focused
on as preparations are made. We're talking a few, maybe three months before
this thing has blown up from an insignificant 1 in 2M and impacted most
people's lives indirectly. What people have a hard time imagining is that
something can go from insignificant to significant so quickly.

------
whatshisface
> _But many medical professionals think in terms of what are called “normal”
> statistical distributions. If someone visits your office with what appears
> to be a typical flu case, it is usually exactly that._

These two sentences are completely, absolutely unrelated.

~~~
koheripbal
Obviously, it's a flawed argument, because the x-axis in this distribution
would make no sense.

...but you clearly know what they are _trying_ to say: Among the population of
people today with flu symptoms, the vast majority of them are influenza and
not covid19.

I wonder if this is still true in places like Wuhan. I also wonder if we'll
see a decrease in influenza next season due to the all the people adopting far
better hygiene habits this year.

------
tuna-piano
For the people who think it will grow exponentially (seemingly most
epidemiologists), China's job in taking an uncontrolled outbreak and at least
temporarily controlling it seems quite surprising. How was China able to
control it, and why can't that happen in other countries? Their efforts are
really quite extraordinary.

"I think people aren’t paying close enough attention. The majority of the
response in China, in 30 provinces, was about case finding, contact tracing,
and suspension of public gatherings — all common measures used anywhere in the
world to manage [the spread of] diseases."

(The above quote and both of these excellent articles are from the same
primary source, Bruce Aylward from WHO):

[https://www.nytimes.com/2020/03/04/health/coronavirus-
china-...](https://www.nytimes.com/2020/03/04/health/coronavirus-china-
aylward.html)

[https://www.vox.com/2020/3/2/21161067/coronavirus-
covid19-ch...](https://www.vox.com/2020/3/2/21161067/coronavirus-
covid19-china)

Will this be enough to pause it for a long period of time? Or will it come
roaring back once china lets their foot off the brake? Or will China
extinguish the virus in their own country and have to block travel inbound to
keep it that way? We shall see.

~~~
whatshisface
If you go around welding people in to their apartments, well, the virus will
probably slow down.

~~~
dwd
Were this the zombie apocalypse, people would be signing up left and right.
Corona virus carriers just don't have the same menacing appearance as zombies,
so everyone's still blase like it's climate change (which has a greater
potential to kill more people - just not right now).

------
Leary
Rather, people should adopt a S-curve mindset, where the shape of the curve
depends on the effectiveness of mitigation strategies.

------
Grue3
How about evolutionary growth model:

\- severe cases are quarantined

\- mild cases keep spreading

\- evolutionary pressure causes the virus to become less deadly

\- deadliness drops to flu levels at which point it stops being actively
tracked

~~~
AstralStorm
Alternatively it does not spread effectively enough (not enough reservoirs in
summer) and dies out in human population.

Or widespread herd immunity reduces its severity, not mutation. (e.g. Polio)
In the latter case, we would have some slight persistent number of cases.

------
oldgradstudent
What's the false positive rate of the test?

The UK has test 16,659 people and confirmed 85 of them, ~0.5% of those tested,
as infected.

How many of them are false positives, if any?

~~~
srl
(I don't know, and have been trying to find the answer, and have failed.)

Best I can do: Assuming that tests performed in different countries are
comparable [1], your statistic would set an upper bound on the false positive
rate, which could then be applied to other countries. The U.S. has performed
3.6k tests and has ~150 confirmed cases. If the false positive rate is the
same, the vast majority of those cases have to be real.

[1] Big assumption.

~~~
oldgradstudent
The assumption may be wrong:

> The rollout of a CDC-designed test kit to state and local labs has become a
> fiasco because it contained a faulty reagent.

[https://www.sciencemag.org/news/2020/02/united-states-
badly-...](https://www.sciencemag.org/news/2020/02/united-states-badly-
bungled-coronavirus-testing-things-may-soon-improve)

------
erentz
They’re both right. We are in a phase of exponential growth. If we don’t check
it it will absolutely overwhelm the medical system. But eventually we will
have crossed the peak and reach a level more like a base rate. I don’t get the
“base raters” position here, it seems they’re living two years in the future
rather than concerning themselves about what happens on the way to that point.

~~~
tuna-piano
If I understand "base raters" correctly, they are not saying anything in
particular about this virus, just that in general due to all available factors
(including human+government intervention), the world generally stays close to
the same.

A month ago, if you asked a base rater and an exponentialist to make guesses
on how many cases in China there would be today, I think the base rater would
be much closer to actuality than the exponentialist (after all, their new
daily case volume stopped growing almost a month ago!).

China was able to pause this outbreak, maybe they can hold it, maybe the rest
of the world can too. I'm not holding my breath but it does seem like a
possibility.

~~~
erentz
I see. That seems useless then isn't it?

I mean its fine if you're looking at the longer term picture. But its
completely useless for informing how to handle an emerging situation. E.g. if
China's decision making was informed by base rater thinking, which amounts
here to "eventually things will return to normal" then they would not have
taken the measures they took which are leading to that.

~~~
tuna-piano
I'm just guessing too on what base rater is, but if I'm correct on what a base
rater is, then the thinking has use for how normal citizens should prepare
(maybe don't sell all your investments to buy rice and beans and N95 masks)
rather than what those fighting the virus should do.

If my understanding is correct, the base raters don't say that nothing extreme
ever happens, they only say that things usually turn out close to how they
have been. I suspect that is true.

------
olalonde
But is the number of cases really growing exponentially? The logarithm graphs
over at
[https://www.worldometers.info/coronavirus/](https://www.worldometers.info/coronavirus/)
seem to indicate otherwise but maybe that's just China's successful
containment efforts skewing the data?

~~~
whatshisface
According to the WHO, China is running a massively successful quarantine
campaign at the expense of pausing their entire country. However, cases
outside of China are still growing exponentially. Check out that plot - it's a
straight line on a log scale.

~~~
Barrin92
> However, cases outside of China are still growing exponentially.

Arguably because we're still catching up with the initial wave of outbreaks
that could develop unhindered. (as was the initial wave in China).

It would be very surprising, based on total population and density alone, if
any other country sees more cases than China with maybe the exception of Iran
which appears to be in disastrous shape.

------
Techies4Trump
Getting data from
[https://gisanddata.maps.arcgis.com/apps/opsdashboard/index.h...](https://gisanddata.maps.arcgis.com/apps/opsdashboard/index.html#/bda7594740fd40299423467b48e9ecf6)

My gut feeling is that far more people have this virus than the Johns Hopkins
app says.

The biggest outbreak outside of China seems to be Iran, with 2,922 confirmed
cases, 92 deaths and 552 recovered. This does sound bad since that is
technically a 3% death rate, but my gut feeling is far more Iranians actually
have it, but are not checking themselves into hospital because they don't want
to be put in quarantine and would rather just stay home.

I'm not trying to downplay the seriousness, Corona virus still is something
you don't want to get, but it probably won't kill you if you're a reasonably
healthy person.

Unfortunately it will probably sweep the world before a cure is found, so
we'll all be exposed to it eventually.

~~~
MarkMMullin
Except for some of us who come from the time you had to get permission to get
an ID on the Arpanet. In that case, the WHO is not saying mathematically nice
things about us. :-(

------
AstralStorm
Why would anyone even remotely skilled in math consider a viral spread
exponential rather than logistic or Weibull?

The former stems from communication theory and the observation that few people
can be sick forever or more than once. There are also constant factor
communication "costs" to the virus expressed as likelihoods of infection due
to minimum effective viral load, countermeasures, severity and immunity.

Latter if fomites are a major factor in final spread. (overlapping point
scatter gets you Raleigh - you have to be unlucky to be near the source)

Potentially a combination of both. They all look sigmoid.

The stronger the countermeasures, the lower the total maximum.

------
alexandercrohde
Non-article. Tl; dr: Some people think corona is going to spread a lot, others
don't.

------
donclark
I get the feeling that its a double edged sword. Do you close schools(and
more) to prevent the disease from spreading, or just overload hospitals with
more patients? Either way, its going to hurt the economy. Which is better
choice - is still being decided.

The problem is quarantine is not enough. We cant test fast enough - or at all.
So is the only choice to keep people from gathering?

~~~
dwd
Quarantining the most at risk and those who look after them could be the best
solution as far as reducing deaths.

They keep saying don't wear facemasks but if you are a asymptomatic carrier a
facemask will limit you spreading it to others. And if everyone wore a mask
correctly you then have two barrier protection. The problem is we don't have
enough masks, and would quickly run out of them for health workers dealing
with confirmed cases.

~~~
AstralStorm
The problem is that _asymptomatic_ carrier is everyone. Face masks are not
free yet, nor comfortable, not everyone will want to wear them, much less
correctly.

------
skzo
This guys understands exponential growth! Outstanding...

------
Animats
The closest historical match is probably the 1957-1958 Asian flu epidemic.
Airborne spread. There were complications in 3% of cases with 0.3% mortality.
68,000 deaths in the US, 2 million worldwide. Stopped by a vaccine developed
after about a year.[1]

Live graph and map of current epidemic: [2]

[1]
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2714797/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2714797/)
[2] [https://hgis.uw.edu/virus/](https://hgis.uw.edu/virus/)

~~~
AstralStorm
We do not know mortality of this coronavirus truly yet, much less number of
cases. It seems to spread somewhat less easily than flu, similar to other
coronaviruses already known - like about 15% cases of cold. Potentially spread
also shows seasonal nature.

I'd like to see rates and complication rates for common cold caused by
coronaviruses.

------
neonate
[https://archive.md/yd4me](https://archive.md/yd4me)

------
subsubzero
I'd put myself in the growther camp. In comparing it to ebola and SARS I think
it is very different. With ebola the rate of death was very high, and very
fast. It couldn't spread quickly due to areas of infection dying out quickly,
plus it was blood borne and the Congo is not hyper connected to the rest of
the world. For SARS the world got lucky there, again it had a higher rate of
death than COVID-19(10% mortality vs. ~3%) but China back then(2003) was a
different beast than China 2020. Its a lot more tied in to the global economy
and overall now has a higher standard of living ( more tourism, more business
flights).

For COVID-19 which is extremely concerning, based on current medical knowledge
is that people without symptoms can transmit the virus, and that the virus
could take 14 days to present symptoms. Looking at exponential growth in cases
at South Korea and Italy show how fast its spreading. Good news is governments
are seeming to take it seriously and remdevisir and a few other drugs looks
promising to fight it given a vaccine is a ways off.

------
lubesGordi
Pointless article. Posits people fall into two camps, the smart people who
understand exponentials, and idiots who don't. Guess where the people in
Washington, D.C. fall.

~~~
Enginerrrd
Not at all. If you know the context of superforcasters (See Good Judgement
Open) they are the only ones who are consistently good at making forecasts.
Even most experts fair no better than chance. And they rely on detailed
assessments with a combination of different sources and lots of analytical
work.

~~~
whatshisface
But what's the base rate here, the base rate of years that have pandemics, or
the base rate of exp(t) functions that go up really fast?

------
aaron695
It's a good point, HN thinks after 60 years of sucking and being useless
Augmented Reality (AR) is going to go exponential this year!

But then someone in the Valley did beat a hell of an old Taxi institution
exponentially.

------
ck2
Meanwhile the trump administration is hiding statistics and desperately trying
to privatize testing as fast as physically possible so the test counts/result
counts are not available as public analytics.

Surprised few have noticed this. It's a bit insidious because the cases are
going to explode.

~~~
whatshisface
Forcing every test to go though the highly limited CDC was a terrible policy
move and was definitely worse than letting the hospitals do it. Trump has some
blame here because it should have been changed sooner, but letting hospitals
run tests is likely to increase the number of known cases. The former (under
Obama I think) FDA head was against the ban that Trump lifted.

------
nwah1
Very accurate division between the two mindsets. Considering the overwhelming
base-rate bias, the contrary growth bias is the one that is in need of a
larger voice.

Also, there's some reasons to think this may be different than these other
outbreaks. One reason is that plenty of smart people suspect this was an
accidentally released bioweapon, given the ground zero was so close to China's
only bioweapons facility.

~~~
cdblades
1) no they don't.

2) even if they do, that doesn't mean a single thing without any kind of
supporting evidence.

