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:
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.
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.
> 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.
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.
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.
Yeah, local non-imported cases in Singapore look like they've been increasing exponentially since at least the start of March, as does the number of cases completely unlinked to any previous travel or known case. That last one is particularly worrying because it's likely to be a very laggy indicator of a much bigger pool of undetected cases - because Singapore traces contacts backwards aggressively, the disease has to have been circulating undetected for quite a while beforehand in order to cause this, and since unlinked cases are much harder to detect they're probably not finding most of them. I don't think this is just restricted to foreign worker dorms either, though those are a big problem right now; this seems to go back well before they found all those case in dorms.
> local non-imported cases in Singapore look like they've been increasing exponentially since at least the start of March
MOH provided an annex[1] breaking down new cases by transmission type in the latest update. The data shows that local cases had been increasing, but they're in a slow decline - for now - and most of the new infections are in or related to dorms.
That chart does not look reassuring. The infections in or related to dorms only showed up at the start of April, presumably in part because they started mass-testing those workers around then. The number of non-imported cases has been going up exponentially for much longer than that. Also, they're likely to have a much higher detection rate for those workers than everyone else right now given that's where testing attention is focused, so they probably make up a much lower proportion of actual infections than the figures suggest.
S. Korea, as I understand it, also assigned a trained case worker to every single case or suspected COVID case. This enabled the contact tracing to be quite successful, and something I believe we’ll need to emulate in the US to prevent the next outbreak in the fall.
To add some real-world data to that: In the supermarkets I visit, all over town, the use of carts/drag-carts is forced, they're generally not cleaned by staff, and in the aisles there's a general awareness of avoiding each other and particularly staff, but it's not observed diligently.
I'd say the biggest vector of disease is people not washing their hands before or after visiting the supermarket, and the free-for-all aisle traversal. It would probably take one infected person to sneeze in an aisle to infect lots of other people traveling through said aisle. or infected employees touching various products with their snotty hands.
I can't tell if that's significant, but as a general rule I assume supermarkets are places to visit as infrequently as possible, and to wash my hands before and after.
For the most part it does seem people are changing their behavior though, around here. we pass each other with appropriate distance, and we stand in line with appropriate distance.
It's not like the saran wrap is going to repel anything, it's just easier than cleaning.
Credit card processors and stores working to turn off signature verification (the olds will just have to deal) would make a bigger difference than infrequent cleaning anyway.
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".
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.
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.
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.
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.
In an open space (such as a supermarket carpark) the Bluetooth LE range could easily be 10-20 meters. So one person standing in the queue could potentially be considered a contact of the 5+ people in front of them plus the 5+ people behind them.
If you're not prepared to test all of those people (and potentially multiple times) then what action should the potential contacts take? Should they all isolate themselves for 14 days because they were in the same carpark as a confirmed case for a few minutes?
Indeed it cannot work without very widespread testing. We'd need the capacity to test millions of cases a day - maybe 20-30 million. Just testing all our front-line health care providers daily would require many millions of tests. There is currently no one in the United States developing a plan to test at even a small fraction of that scale. It is definitely possible, but would require an administration capable of doing something other holding press conferences and tweeting malice and misinformation. So, maybe next time?
Bluetooth beaconing can estimate the distance between two devices (and does better if, eg, given 10 seconds to estimate vs. 1 second).
I assume a covid-19 contact tracing system would use this, among other things, to filter out contacts that don’t meet the established criteria for high enough risk of transmission.
2 meters is only sufficient for droplet transmission (e.g. breathing). Aerosol transmission (e.g. a sneeze or heavy cough) can travel much further than 2m. Granted these are for confined spaces and outdoors it will depend on factors such as the wind. But 10m sounds perfect.
At the moment we are all isolating for months. So yes if 5% of the population needs to isolate because they were 10m away from someone who had it then so be it. I'm perfectly fine with that.
You have aerosol and droplet mixed up. Aerosol is much finer particles than droplets. Sneeze would be droplet (plus aerosol), breathing would be aerosol, likely not droplet. From what I've read it's not clear that aerosol would be limited to 2m, e.g., if it were allowed to build up in enclosed space.
But in any case it's all on a curve, the further away you get the less likely a person will be infected.
That's the opposite of what I heard, that breathing mostly produces droplets. But I wouldn't be surprised if it's wrong, it seems like this area of research is not well understood by public health professionals. Regardless of droplets or aerosols, sneezes definitely have a high velocity and travel further than 2m.
And yes it's a curve so the risk depends on the minimal infective dose. If you can get infected by a small number of virus particles (which is apparently the case) then you need more distance.
presumably that is a pretty accurate sample of people likely to be infected by me. All the shoppers in the supermarket while I am (and shortly afterwards) are at risk of picking up the satsumas I fondled too much etc.
(to be clear, I'm operating a 'touch means take' policy, but its clear through simple observation that most aren't capable of thinking through the rule (or even following it))
That's contact tracing and how to act on the information.
As mentioned it's probably not possible to get better than that with a technological solution but it is much better than not using technology.
It's also difficult to define what 'better' would be. Seems to me that all those people should indeed be careful and self-isolate.
For what it's worth, I agree with you and believe your concerns are well-founded.
I'd also note that the comment you're replying to didn't really address your two original points. Instead it stated some technically-correct but conversation-misdirecting facts.
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).
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.
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
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.
Which of those things do you think are both feasible and able to turn around the virus in the required timeframe?
Improving medicine: decades?
Improving vaccines: 12 ~ 18mo
Improving detection: ???
Isolation of elderly: presumably already in place (are you suggesting something more?)
Improving healthcare: ??? (anything specific?)
I don't think any of these are going to make much of a difference to this pandemic. The vaccines eventually, perhaps. The things that have been shown to work well are NPIs (non-pharmaceutical interventions) such as: contact tracing, testing, mask usage, social distancing. The system that Apple/Google will put in place is essentially automated contact tracing. It will be much faster and have more data than manual contact tracing.
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.
If you are concerned about this, the app is the least of your worries because BLE and MAC addresses are already being used to track your movements, for commercial purposes. For example inside stores.
Additionally, many many apps silently gather and sell this data, without your knowledge, and with "consent" being ignored or being relegated to privacy statements that are too vague to understand that they are doing this.
I really hope that if people are concerned at all in any way about the tracking app mentioned here that they also learn that such tracking is being used extensively in industry right now.
I'm surprised how few people on HN seem to know this. If any audience should know and warn our friends and neighbors, it's the audience at HN.
So we get the reverse of the reasonable behavior. People - and I mean tech people, not Joes and Janes Random - freak out over using movement tracking to fight a pandemic, while they willingly accept the same tech being used by advertisers.
by all means, you are free to make this tradeoff for yourself. but you don't get to decide what other people's privacy should be worth to them.
> 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.
do you live in the united states? there have been quite a few privacy fiascos in the last couple decades that the general public found unimaginable until they were exposed.
The whole idea is that the app would alert you if you may be infected so that you don't go out.
The problem is that sometimes people who don't yet know they are infected have contact with other people before anyone in the story finds out that they are infected. The apps allow the communication to happen:
1. Even if the people who had contact don't know each other.
Contact tracing is a precursor to testing. An app flagging you as a potential positive doesn’t mean that you self-quarantine for x days, rather it means that you get tested asap. And this has to happen every time you get flagged. Otherwise there’s just no point in using those apps. Eventually the entire neighborhood would be flagged.
Is this all this tracking achieves? I personally assume that I'm infected until proven otherwise. Even if proven, I can get infected a day later. I don't need a tracker to tell me this.
1. The US, despite currently suffering the most, will probably not end up being the country with the most casualties. Once covid-19 takes hold in more densely populated poorer countries, there will be immense suffering.
2. 1918 flu cost up to 100 million lives, 1957 flu about a million lives, and 1968 flu about a million lives.
3. Total deaths worldwide is already >100k, and the known cases are still less than 0.03% of the population.
Would I give up my privacy to save a few thousand lives? Yes, but the scenario is incorrect. There isn't really a privacy sacrifice involved. I'm trying to think of the worst-case scenario in terms of privacy, but there just isn't one. Someone finds out that a device with ID 00:11:22:33:FF:EE spent 15 minutes with a device with ID 01:31:24:53:EF:AE. It's not worth so many people losing their lives for.
It’s also surely an undercount in the US. We’ll get accurate numbers when all cause mortality comes out. In Europe the totals were underestimated by a factor of two in most countries.
For example, in NYC, this chart shows roughly 5500 excess deaths on april 4th. Whereas on that day nyc had only counted 3500 coronavirus deaths.
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.
“Fox and OAN” are not the same as “news stations”. If you got your news anywhere else this was reported accurately by the middle of January[1] and there were plenty of experts calling for social distancing by February. The decision to politicize medicine will go down in history’s list of bad calls but it’s a function of the right-wing propaganda network, not the news media or public health experts.
1. Yes, there was that dweeb with the NYT opinion piece saying it wasn’t worse than the flu. There’s a reason that ran in the opinion section.
US already has 20k deaths and only 500k confirmed infections. Not all of those infections have had an outcome and not all infected have been confirmed so it's hard to do an exact calculation but based on that data more than a million deaths is very likely. So yeah, it's worth it.
Plus you're saying that based on the current data. The fatality rate only worsens as the infection rate goes up and hospitals become even more overwhelmed.
True, but no estimate is lower than 0.3%, which is still very high (600,000+ dead in the USA). The next step in walking back the fatality rate of course will be to define an IFR that's "net of people who were probably going to die soon anyways".
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!".
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.
If it looks so, that's only thanks to lockdown. There were days where the US saw daily 40% increase: with that kind of curve, it takes five days from "hospitals 80% idle" to "full", and another five days from that to "five times more patients than we can handle".
And since it takes about a week for infected people to show symptoms, when you put the brake again and re-implement lockdown, you will be looking for another five-fold increase before it slows down.
Shutting down business and being forced to isolate is already surrendering a liberty. We understand it's temporary, no reason the same can't be true of contact tracing or why at the very least volunteering the information through apps isn't facilitated.
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).
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.
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.
> 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?".
Agreed. Also, due to the indiscriminate cancellation of "elective" surgeries (which include things like bone marrow transplants), my mother's hospital is slower than normal! They're facing a funding crunch as a result and may need to cut staff. This is the insanity of centralized policy making when the distribution of impact is not even in all districts.
Do you realise that thus far about 0.1% of the population has been infected, but herd immunity requires somewhere between 60% - 80% of the population to be immune? A vaccine will be available much quicker than herd immunity obtained through infection unless you do want to go through the overwhelmed hospital system (or just no hospital system) for many months.
Do you realise that immunity for this virus may not be lasting?
Your plan requires millions more lives be sacrificed just so that the ID of one of your many electronic devices isn't recorded by some other devices. It's already public anyway, by the way. That said, this plan wouldn't happen anyway. People will not willingly be infected. Herd immunity through infection is not possible.
Not with certainty. I'm stating the population that has been tested positive in the US. I apologise, as it's actually more like 0.16% (per https://www.worldometers.info/coronavirus/country/us/), so call it 0.2%. Let's even go so far as to assume that there are 10x as many people infected who haven't been recorded. That would make it 2%. Herd immunity through infection is still 30x - 40x away from where the US population is. Vaccine will still be sooner unless allowing for the hospital system to become overwhelmed.
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.
Covid-19 in S. Korea @5:13
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.