
Contact Tracing in the Real World - nmjenkins
https://www.lightbluetouchpaper.org/2020/04/12/contact-tracing-in-the-real-world/
======
redis_mlc
Going a step beyond the info in the blog post, there's a documentary on
Youtube showing how in S. Korea, there are apps to see the paths of corona
patients so you can avoid those areas:

Covid-19 in S. Korea @5:13

[https://www.youtube.com/watch?v=BE-
cA4UK07c](https://www.youtube.com/watch?v=BE-cA4UK07c)

My opinion is those apps work because S. Korea remembers SARS-1 (2002/2003),
and people there are cooperative. Also, if you do full contact tracing early
enough, there aren't an overwhelming number of patients like NY.

S. Korea is the only country that literally "flattened the curve." See
unbelievably flat graph @6:50 in link above.

(S. Korea had the same problem as Toronto with SARS-1, where the hospital
doctors and nurses were wiped out by the first few cases. In S. Korea, it was
the first SARS-1 patient wandering around town like a cruise missile to
several doctors and hospitals that spread the disease, as nobody identified
the magnitude of the problem.)

> And how will things work with an orderly supermarket queue, where law-
> abiding people stand patiently six feet apart?

In the SF Bay Area, here's how social distancing works at grocery stores:

1) one entrance/exit with security guards at the door

2) queue outside with shoppers 6' apart

3) only 50 people allowed in at one time, but distance is not enforced in the
store except 6' in checkout lanes. However, American grocery stores are large,
so the spirit is being followed. Recently, I've seen saran wrap over POS
terminals. Bank ATMs also need that prophylactic. :)

4) shoppers are responsible for washing their carts and hands, which is a gap.

~~~
sfj
> S. Korea is the only country that literally "flattened the curve." See
> unbelievably flat graph @6:50 in link above.

Taiwan has also done so. It has a similar story, burned by SARS, also.

[https://www.cdc.gov.tw/En](https://www.cdc.gov.tw/En)

~~~
maxerickson
Taiwan, Singapore and Hong Kong all basically avoided the problem up front.

They basically don't even show up on graphs that show positive test counts for
other countries.

I've had people argue that this is containment rather than flattening the
curve, but I think it's both, it's containment, which is roughly the limit
condition for flattening the curve.

Now they are showing us the future, with new outbreaks showing up.

~~~
xvilka
Cases in both Singapore and Hong Kong are on the rise, so it's a bad example
of the containment, unlike South Korea one.

~~~
culturestate
Singapore cases are rising, but primarily within a specific sector of the
community (foreign worker dorms, which were always a concern as they're very
communal spaces). We've been in a de facto lockdown for a week now, so the
next few days will be telling.

Hong Kong, for its part, reported only 4 new cases on Sunday and has been
testing aggressively - I think they're around 15,000 tests per million people
now.

~~~
chrisco255
Yeah but as soon as they lift their draconian measures they are going to get
hit with it. This virus is too infectious to contain or control. Meanwhile,
economic suicide is going to bring poverty and ruin to billions of people if
this carries on.

------
slothtrop
I'm disappointed that some I've come across are trying to cast SK's measures
as tyrannical, as though it's not authoritarian to shut down the economy and
force everyone to stay home. Cooperating with contact tracing is a lesser
temporary loss of freedom than not working. It's not even clear to me to what
extent it helped, all the articles I've read repeatedly state that early
testing in itself has been the deciding factor. In theory then, if the
infection rate were temporarily quashed, couldn't this be implemented?

And both sides of the political spectrum are behaving this way, the right-wing
downplays the risk and postures that a lockdown will lead to a worse outcome,
and many dems pretend a lockdown is the only thing that could have
realistically been done, looking to SK like "oh, well they're draconian, that
could never happen".

------
rubidium
Here’s the real deal. I’m quite privacy conscious. Hate tracking of any type,
esp. for some mega corps profit.

That said, I’d gladly install a decent security verified app that tracks me
for the next 3 months. I’d be happy to self isolate again with my family (as
we’re doing now) if I came in contact with someone. But the big issues are:

\- ensure tracking is available only to those who need it and doesn’t get
shared with any commercial interest.

\- my employer supports WFH or short term paid sick leave (maybe with gov’t
assistance) for those 14 days.

Get those two things and I think the majority of the US population would opt
in. That would be sufficient.

Sure there’s some risk that people are infected who won’t opt in. But that opt
in system of “we’re all in this together” is much better than a forced gov’t
tracking system.

------
kiwidrew
I applaud the efforts to investigate whether smartphone technology can be a
useful aid in the contact tracing process.

Privacy aside, it seems to me that there are two main issues that Bluetooth-
beaconing-smartphones will struggle to solve:

1\. Determining whether two smartphones "hearing" each other's beacon
constitutes contact between the owners of those smartphones. (The blog post
we're discussing brings up several examples, and the "orderly supermarket
queue" of shoppers patiently waiting outside while observing a 2m distance
could generate a massive number of false positives.)

2\. Ensuring widespread adoption. If only 1/6th of the population is
participating (which are the numbers Singapore is seeing so far) then the
chance that an encounter between two people is captured by the app is 1/36th
-- far too low to be of much use. There is also an upper limit to adoption
because not everyone owns a smartphone or has a device which would be
compatible with the contact tracing app.

~~~
arrrg
False positives are ok, even a massive amount of false positives.

Currently we all have to change our behaviour around everyone, all the time.
Even if you are in New York that probably means there are “false positive”
behaviour changes (behaviour changes for no reason) all the time – simply
because we lost control of the situation and cannot currently contact-trace
our way out of that situation.

The idea behind these contact tracing apps is that they make only really sense
once you have to outbreak well under control (through drastic measures). The
goal is then to relax measures (probably not to abandon all of them –
handshaking is probably dead and the recommendation will remain to stay away
from other people in public and forget large gatherings for a long time, as
well as a lot of travel …) and be much more targeted with who you impact
through such contact tracing.

Obviously they cannot replace proper contact tracing, but they can be a
helpful tool in the tool-belt and increase the effectiveness of standard
contact tracing and testing.

If there are, say, 500 detected active cases in a country like Germany (which
is probably around the limit of where contact tracing still works, even with
many more people working contact tracing and much expanded testing capability)
contact tracing apps can provide an additional signal and increase the speed
of standard contact tracing approaches, especially since we know that much of
the spread is pre-symptomatic.

Even if this tool overestimates the infectious contacts someone had
hundredfold and we assume a ridiculous R0 like 10 (so someone infects ten
people on average but a hundred times that many people are actually detected
by contact tracing – so 1,000 people altogether) that would still only place
at most 500,000 people in quarantine (assuming an upper limit of 500 detected
active cases that can be handled before you lose control again and have to
place the whole country under lockdown).

That’s a huge number but probably not as impactful at all as the current
measures that are in place. (Obviously you need to put measures in place to
make that possible: mandatory, automatic and paid sick leave for anyone who is
told to stay at home for a week or symptom-end plus one week. Stuff like that.
Some countries are probably better prepared for that than others.)

Even this blunt instrument would be much better than the current situation.

~~~
reitzensteinm
Yes, and the author's description of being notified for having been within 3
meters of someone with Covid as being "punished" with "false alarms" makes me
want to tear my hair out.

If contact tracing were enabled and everyone at any risk self quarantined this
nightmare would soon be over. Instead people will justify why they're low
risk, interact with others and continue the spread.

------
dchyrdvh
Apple, Google, Facebook already track everyone and everything they can: all
these gps, wifi, Bluetooth and even ultrasound trackers built into smartphones
exist only for one purpose. After all, they are in the business of building
accurate user profiles and selling ads to them. What they do need is ability
to do this openly, so they're trying to leverage the epidemics to legalize
their business (ATM it's in the grey area: kinda legal, but amoral).

------
pintxo
Some interesting thoughts:

> First, it isn’t anonymous ...

I believe this is a miss understanding. We loose anonymity once someone is
diagnosed, there is no way around that. But we should not skip on anonymity
for everyone else. Else this whole project is doomed by the onset as we are
simply building a massive 1984 style infrastructure.

> Second, contact tracers have access to all sorts of other data such as
> public transport ticketing and credit-card records ...

Which is debatable, but not a major problem as long as this is a largely
manual ad-hoc process regulated by law and so expensive to execute that we
only do it during emergency situations. It's totally different once we start
building systems and processes around this to make it cheap and it ends as the
new normal.

> Third, you can’t wait for diagnoses. ...

Surely a problem we need to improve upon. Likely a major logistics problem?
Maybe something we should ask the military to take a look, after all logistics
is something they might have an idea how to do right.

> Fourth, the public health authorities need geographical data for purposes
> other than contact tracing ...

Why would this need to be part of contract tracing? Currently this is done
based on confirmed cases. Surely they are largely localized, especially since
the stay-home orders.

> Fifth, although the cryptographers – and now Google and Apple – are
> discussing more anonymous variants of the Singapore app, that’s not the
> problem. ...

I agree, trolling, denial of service and school kids are going to be a
problem. Could likely be solved by adding a formal gate for infected. Signing
the test result with a public-private key scheme should do the trick to
prevent any non-legitimate results being used to trigger events.

> Sixth, there’s the human aspect.

Interestingly I would have said this is the technology aspect. How many
contacts will we miss because bluetooth low energy is not up to the job?

> Seventh, on the systems front, decentralised systems are all very nice in
> theory but are a complete pain in practice as they’re too hard to update.
> ... Relying on cryptography tends to make things even more complex, fragile
> and hard to change.

Seems solvable, considering we are talking about mobile apps, mostly always
online, managed through central app stores and servers? Sounds doable.

> But the real killer is likely to be the interaction between privacy and
> economics. If the app’s voluntary, nobody has an incentive to use it, except
> tinkerers and people who religiously comply with whatever the government
> asks.

Tend to agree, although we have seen quite some adherence to sensible rules
the last couple of weeks. Maybe we will be surprised by our fellow humans,
maybe not.

~~~
antpls
You must admit : even if you have some answers to those concerns, it's a lot
of "doable", "should be possible", "seems solvable", etc.

If a solution generates that much sceptisism, that many questions and requires
that much energy to convince each others, it's a big red flag.

~~~
pintxo
It's a question of alternatives, isn't it?

Operation Overlord was nothing any sane person would attempt if there was a
viable alternative.

~~~
antpls
True, and there are plenty of alternatives : improving medicine, improving
vaccines, improving viri and molecules detection, early isolation of ederly,
improving healthcare, ... None of those axes requires to give up our privacy.

People pushing the "we must do that or millions will die of this deadly virus"
have been proved wrong so far

~~~
pintxo
Contact tracing is not about saving lives. It’s about saving the economy
without killing people.

As you say, we have other measures to save lives, but it seems they are rather
deadly on the economy, and human (social) life as we know (and like?) it.

------
jfoster
If I go outside, I would like to have an app that does this on my phone. My
"right to privacy" isn't worth putting other peoples' health at considerable
risk for.

There isn't even a scenario I could imagine where one of these apps would do
something that I would consider a severe infringement of my privacy.

A few million lives may ultimately hang in the balance, so there ought to be a
very compelling argument against not putting these apps into practice and
getting ahead of coronavirus.

~~~
mrfusion
The US is predicting 60k deaths. Millions is quite an exaggeration. Would you
still give up your privacy to save a few thousand lives?

~~~
andruby
60k deaths in the US on a population of 330M, guess how much that would mean
for the world? 7700M/330M * 60K = 1.4M.

OP is absolutely right.

Countries with lower standard of healthcare than the US will have a higher
death rate.

~~~
Zenbit_UX
The US is an extreme example, their news stations were downplaying it and
calling it a hoax, they didn't follow social distancing in most places until
it was too late, they were late to the "this is not the flu" party by a month
and grossly incompetent leadership combined with the CDC literally lying to
its people === the perfect storm.

Further, those numbers are based on NYC hospitals being completely overwhelmed
which sky rocketed the death rate. If a country can flatten their curve what
is happening in New York doesn't have to happen again.

~~~
rootusrootus
The US is pretty much in the middle of the pack when it comes to how typical
western democracies have responded to the crisis.

------
tcd
Not trying to be cynical, but to me this seems to be a way to get the mass
public "okay" with contact tracing. Then somehow they "mysteriously" manage to
get more accurate information from other sources (location, wifi beacons, data
sharing etc).

But they'll just say "the information is only from this source, we pinky
promise!".

------
hcurtiss
When did “flatten the curve” become “eliminate transmission”? We have abundant
hospital capacity remaining nearly everywhere up in the US. It seems likely we
can begin moving toward herd immunity significantly more quickly by relaxing
social distancing standards and quarantining sensitive populations, all while
remaining below the horizontal line. It’s not worth surrendering civil
liberties, something we’ve sacrificed many lives to preserve.

~~~
maxerickson
Define "sensitive populations".

Also, define how you (effectively!) quarantine sensitive populations with less
impact on civil liberties than testing and contact tracing of the general
population (which has modest privacy implications that can be reasonably
managed).

~~~
leetcrew
by definition, sensitive populations face the greatest personal risk from
violating the quarantine. most of them would probably comply if the government
merely asked them.

it's hard to see how contact tracing of the general population can be done
with "modest" privacy implications, unless it's opt-in.

~~~
maxerickson
What about the thousands of people that work in nursing homes?

Protecting the people they care for means imposing restrictions on them. And
so on for all sorts of other people that would be involved in (effectively!)
isolating sensitive populations.

The reason contact tracing has modest privacy implications is that the
location history of most people isn't sensitive information (or exists
already, with little additional harm incurred by giving it to public health
workers). It's fine if you disagree with me on that point, but that's my
argument, it isn't super serious if Bill over at the county health department
sees that you encountered a sick individual at Wendy's, which is going to be
the majority of the data.

~~~
leetcrew
> What about the thousands of people that work in nursing homes?

I wouldn't necessarily oppose stricter measures for people who do this sort of
work. easy for me to say when I don't work in a nursing home, of course. in
principle, it would be comparable to the privacy you give up when you have to
get a security clearance for your job.

> The reason contact tracing has modest privacy implications is that the
> location history of most people isn't sensitive information (or exists
> already, with little additional harm incurred by giving it to public health
> workers). It's fine if you disagree with me on that point, but that's my
> argument, it isn't super serious if Bill over at the county health
> department sees that you encountered a sick individual at Wendy's, which is
> going to be the majority of the data.

I can certainly understand that my position looks a lot like closing the barn
doors after the horses have already run five miles down the road. google has
the gall to actually send me an email each month showing all the places it has
tracked me going. even if I delete my facebook account, it can still recognize
my face in pictures other people take.

I'm not happy about any of this, but at least now, the government has to put
on some charade of formality to access this information. giving it the power
to directly collect this data in plain view is another step in the wrong
direction. it adds more stuff to the pile of things we need to undo to get
where I personally want to be.

I don't think your argument is unreasonable, just that we're approaching this
from different perspectives. you're thinking about "how many people can we
bring with us to the other side?", while I'm thinking more about "what do we
want the other side to look like?".

------
buboard
I think the author is correct that people are missing the forest here. I know
plenty of people that would have no problem with public tracing of patients
(myself included), but it wouldn't be effective in stopping the virus here.
And not because the app's uptake would be small - people are dying to _do
something_ , anything, so they 'd download it. Maybe singaporeans did not
download it because they feel already protected enough by their health system,
but westerners feel so unprotected by them that they buy TP by the metric ton.

S.Korea and singapore/hong kong, those are densely populated areas/cities with
specific movement patterns among people and enough tehcnology infrastructure
to know what do something useful with the tracing information. In some western
cities, tracing would end up giving people constant alarms that they might be
infected, and that information wouldn't really be actionable or at least you
coulnd't trust that people would act on it. Western cities have no memory of
other plagues either.

Perhaps goverments should reward distancing and testing instead of punishing
offenders. Perhaps even pubs could open, provided they serve the same group of
10 people every monday. Western cities will need to figure out their own
policies until a cure is found, and they have to reflect their own character -
you can't just copy asian policies praying that they work.

