
Imperial College report on Covid-19 that led to the extreme measures in US - jimktrains2
https://threadreaderapp.com/thread/1239975682643357696.html
======
Leary
Landmark report not because it's likely to be accurate, but it scared the UK
(and perhaps the US) into action from the high mortality figures based on the
latest Italian data.

However, let's look at how the report underestimates the effectiveness of
interventions:

Case isolation in the home: Reduces non-household contacts by 75% and assumes
70% of households comply : so only reduces non-household contacts by 52%

Voluntary home quarantine: Reduces community contacts by 75% but assumes only
50% of household complies.

Social Distancing: "Reduce contacts by 50% in workplaces, increase household
contacts by 25% and reduce other contacts by 75%. Assume 75% compliance with
policy."

Social distancing of entire population: "All households reduce contact outside
household, school or workplace by 75%. School contact rates unchanged,
workplace contact rates reduced by 25%. Household contact rates assumed to
increase by 25%."

Closure of schools and universities: "Closure of all schools, 25% of
universities remain open. Household contact rates for student families
increase by 50% during closure. Contacts in the community increase by 25%
during closure. "

25%, 50%, 75%... Where did they come up with these figures??

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hnzix
_> School contact rates unchanged_

I'm in a country with mandatory social distancing, and parents are still
having school cricket and soccer matches in the local park. The parents are
all clustered together watching.

They think their children are "immune".

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LatteLazy
"extreme measures" \- the term used before the pandemic.

"insufficient measures" \- the term used after the pandemic.

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thedudeabides5
Tyler Cowen had a great take calling out the tradeoff implied by this paper,
raising the question of if a 18m total lockdown (the upper bound of the
recommendation in this paper) is even a reasonable thing from a
society/utilitarian perspective.

[https://marginalrevolution.com/marginalrevolution/2020/03/he...](https://marginalrevolution.com/marginalrevolution/2020/03/herd-
immunity-time-consistency-and-the-epidemic-yoyo.html)

 _Alternatively, let’s say we start off being really strict with shutdowns,
quarantines, and social distancing. Super-strict, everything closed. For how
long can we tolerate the bankruptcies, the unemployment, and the cabin fever?
At what point do the small businesspeople, one way or another, violate the
orders and resume some form of commercial activity? What about “mitigation
fatigue“?

Again, I fear we might switch course and, again, end up with the worst of both
worlds. We would take a big hit to gdp but not really stop the spread of the
virus.

I also can imagine that we keep switching back and forth. The epidemic yoyo.
Because in fact we find none of the scenarios tolerable. Because they are
not._

~~~
TYPE_FASTER
I've been thinking about it two ways:

1\. We could forecast a projected cost to the global markets, vs. the number
of lives saved, and put a price to each life saved. Every healthcare
conversation has avoided doing this, so maybe this pandemic will force the
conversation.

2\. We shelter in place, take the hit to the market, and use the opportunity
to learn a lot about our impact on the environment, ourselves, and how we can
possibly change as societies to make things better for everybody.

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ramblerman
In the pdf report there is a nice table at the bottom of page 5.

Not only is the CFR lower than I had anticipated, but it made me realize that
a hospital trip doesn't immediately imply intensive care.

For instance a 35 year old has 3.2% chance of going to hospital, and then 5%
chance of ending up in the ICU when going to hospital.

Can I multiply these together to get 0.16% chance of ending up in the ICU once
infected, or is that too simplistic :)

~~~
jbc1
That seems way less dangerous to young people than I'm otherwise seeing
reported, and this is the report that's apparently so extreme it got the UK
and US to finally do something.

What with all the people who are obese, smoke heavily, have asthma, immune
compromised, etc I would have assumed 0.16% of people find themselves in the
ICU if they get a cold.

~~~
8fingerlouie
Italy reported today that 99% of the COVID-19 deaths in Italy had a
preexisting condition.

If you're healthy you (probably) don't have anything to worry about, but if
you're diabetic, smoking, have hypertension or other normally manageable
conditions, you're (maybe) at risk.

And to all the healthy people who seems to think they're immune. You probably
won't die from it, but someone in your close family may very well die because
you didn't take it seriously.

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guscost
I’m not qualified to properly challenge any of this, but it looks like all of
these models use one estimate of the IFR (“mortality rate”). This paper is the
basis for their 0.9% number:
[https://www.medrxiv.org/content/10.1101/2020.03.09.20033357v...](https://www.medrxiv.org/content/10.1101/2020.03.09.20033357v1)

If that estimate is wrong, all of the numbers in the models would be wrong
too. Strange that they tried a range of numbers for infectiousness but only
one basically educated guess for IFR.

~~~
th0ma5
Could be just what they had. I thought we all thought the IFR was higher, in
which case the Central point of it all being urgent is perhaps understated you
think?

~~~
guscost
I _definitely_ do not think that the true IFR is higher. But again, I’m not a
doctor and this is not medical advice.

~~~
imustbeevil
Based on the data here:
[https://www.worldometers.info/coronavirus/](https://www.worldometers.info/coronavirus/)

The current death rate of closed cases is 9%. I guess the expectation is that
it falls once we develop a vaccine?

~~~
odkamkfn
Most infections never turn into "cases", which is why the IFR (Infection
Fatality Rate) is a lot lower than the CFR (Case Fatality Rate). How much
lower is _very, very_ hard to say.

Also note that there's no strict definition for how to calculate the CFR, so
you'll see conflicting numbers even for the same area/country.

------
bitL
I am wondering - coronavirus (the usual one) is associated with common cold;
we don't have any vaccine against it nor do we actually understand the common
cold itself; moreover, COVID-19 has a similar genomic packing as HIV/Ebola,
two diseases we don't have vaccines for either. I am wondering if it is just
wishful thinking we get a COVID-19 vaccine anytime soon (i.e. in the next
decade). Are there any reasons to be optimistic?

Also, regarding herd immunity - we aren't immune against flu, is there any
reason to think we could develop (long-term) immunity to COVID-19?

~~~
nikhilsimha
> we aren't immune against flu, is there any reason to think we could develop
> (long-term) immunity to COVID-19?

Spanish flu became less lethal in subsequent generations[1]. Helps with the
survivability of the virus if it doesn't kill the host. So, the strains with
less lethality win out.

We don't need to be immune for the situation to resolve. Simply co-evolving
with the virus is sufficient

[1] [https://demystifyingscience.com/blog/2020/3/4/patriarch-
of-p...](https://demystifyingscience.com/blog/2020/3/4/patriarch-of-pandemics)

~~~
sliken
Flu's evolve and there's feedback from the behavior of the humans they infect.
So if they make you feel like crap you are less likely to spread the
infection. So that results in a less aggressive infection out competing a
similar but more aggressive infection, doubly so since the immune system will
like cross react between the two.

However with COVID19 the infection seems quite adept at spreading before the
symptoms show, so there's going to be less of a feedback loop. Might even be
the opposite since a serious infection means visiting the doctors office, in
many cases more than once, and finally escalating to the emergency room.
COVID19 seems especially adept at infecting nurses, doctors, ambulance
drivers, and EMTs.

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HSO
I really wonder what future historians will say about this hysteria and the
economic damage it causes.

1) _80% of Americans would get the disease_ That sounds scary (big number!!).
But I'm getting tired of the constant reporting of each and every _infection_.
What is really relevant is infections _of at-risk groups_. Most infections,
_nothing happens_!

2) _8-15% of all Americans over 70 would die._ Newsflash: Old people tend to
die more often than young people. What is the all-cause i.e. normal mortality
rate of the elderly. One number I saw cited: all-cause mortality of 83/84 yo's
in the US ~7 percent. Case mortality rate i.e. _with_ infection in Korea among
80+ yo's: 7.4 percent. What am I missing here? Are the reported covid
mortality rates all normalized by all-cause mortality and they report only
real "excess" deaths or are they lumping everything together? This would be so
mind-numbingly stupid, I really hope I'm wrong about this!

3) _0.9% of them would die._ That's the unconditional number, all age cohorts
aggregated. Split them up and the number is clearly skewed by the large number
of the elderly (and see 2 above). Now factor in that testing outside Korea,
Taiwan etc. is really bad and focused on symptomatic cases. Common estimate of
how high are the true numbers of infected is around one order of magnitude.
Let's assume the official stats are off by a factor of ten. Let's further
assume that young people (say, below 65) are "more social" or mobile than
elderly and thus likelier to get infected. That means a) the undercount is
dominated by younger people and b) the mortality rates are off by more than
ten. At what point are we getting to mortality rates of common influenza?

4) There are basically two ways to die from the virus: a) immune system
overwhelmed by virus or b) immune system overreacts. Younger, healthy people (
< 65 yo) seem to die more from b. Now look into _who_ are the victims in this
cohort and it turns out mostly medical professionals. Due to lack of
preparation and equipment, those medical professionals are exposed to
disproportionately higher or even extreme quantities of the virus. This seems
consistent with b. Also, it means that the mortality rates of younger, healthy
people is skewed by counting medical- and non-medical people together.

In sum, I think this is a total overreaction and panic that causes huge
economic damage (which has a big human cost, in terms of lives lost, as well
make no mistake) for what may turn out to be basically nothing.

What am I missing?

[EDIT: I'd prefer we focus on the at-risk groups (elderly and pre-existing
conditions like obesity, cardiovascular diseases, diabetes, etc) instead of
just blanket- _everybody_. Isolate the at-risk groups until vaccine and/or
medication are developed and let everyone else basically develop herd immunity
until then. Increase testing. And basically use this as a call for more
general health measures, not just virus panic. The immune system depends on
sleep, nutrition, mental health/hormone balance, etc. With the panic and the
economic crash induced by it, all these factors are becoming negative instead
of positive factors for most people now.]

~~~
aparashk
The numbers above don’t hold much under scrutiny.

The "herd immunity" approach is a dangerous gamble, as one of the big unknowns
is "How long is the immunity after recovery from COVID-19" \-- it can be
anything between 0 (no immunity) and infinity (immunity for life). If acquired
immunity holds for less than the time required for a vaccine to be widely
available, "herd immunity" will quickly become a massacre. The first wave will
knock off the medical system (even if somehow everyone over 60 is protected),
ensuring that the second wave will be devastating.

I much rather prefer the South Korea/Singapore/Japan alternative to the UK
one.

The race is to arrest the exponential curve, somehow, at any temporary cost,
for if we don't we can't apply the working options for COVID-19 response from
Japan, South Korea, and Singapore.

~~~
HSO
> _The numbers above don’t hold much under scrutiny._

Can you tell me which exactly and indicate why?

~~~
lozenge
[https://www.theguardian.com/commentisfree/2020/mar/15/uk-
cov...](https://www.theguardian.com/commentisfree/2020/mar/15/uk-
covid-19-strategy-questions-unanswered-coronavirus-outbreak)

[https://www.theguardian.com/politics/health](https://www.theguardian.com/politics/health)

~~~
daaa
Curious about which numbers do not hold. Can you tell specifically? - a news
article tends to cite a lot of numbers - And given the situation, can you also
mention the original sources?

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im3w1l
Here's a scenario I'm curious about. Chickenpox parties for young and healthy
people who are then isolated. Use heavy suppression to make sure there are
ventilators available for them should they be needed.

My gut feeling is that this could create herd immunity at small cost.

~~~
leereeves
I see a possible problem with the idea:

> Chickenpox parties for young and healthy people who are then isolated.

Sign here to be given coronavirus and locked away for a month...

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im3w1l
If you don't sign you are to practice social distancing for a year meaning you
will be excluded from most of society. How's that for an incentive? You see
that is what the article proposes _everyone_ should do.

