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Contract tracing hasn't worked at scale anywhere. It's a nice idea conceptually, but the problem is psychological. People stop caring about tracing when 98% of
by gizmo 6y ago
Contract tracing hasn't worked at scale anywhere. It's a nice idea conceptually, but the problem is psychological. People stop caring about tracing when 98% of all trace connections are false positives. If a person is infectious for a week and the r0 is around 1 then only 1 person of all the people they've been in contact with will actually contract the virus on average. The other 50+ people, assuming they can even be traced, get a false positive. Or to put it differently, people have to be called 50 times and get tested and self-isolate 50 times before they actually test positive. And for younger people 80% of cases are completely inconsequential. You might think 50 contacts is unrealistically high, but most people still go to work, to school, see friends, use public transportation, etc.
Covid19 would also be over if people with symptoms would just stay home. But that's clearly not happening either. We've got to be realistic about how people behave in the real world.
Mutations aren't a serious concern. Because when viruses mutate it's the strains that are more infectious and less lethal that win out.
- mumblemumble 6y agoThere's also participation on the contact side. In Western countries, surveys indicate we can't convince even half of people to install a contact tracing smartphone app. According to my state's department of health, practical experience indicates we can't convince even half of people to pick up the phone and respond to a contact tracing interview. > Covid19 would also be over if people with symptoms would just stay home. No it wouldn't. One of the things that makes SARS-CoV-2 such a problem is that people get contagious long before they show symptoms. Similarly to for influenza and the common cold, many people get contagious without ever developing symptoms.
- mjmahone17 6y ago> According to my state's department of health, practical experience indicates we can't convince even half of people to pick up the phone and respond to a contact tracing interview. More than anything I suspect this is a result of allowing so much unfiltered spam calls. If you only get one unexpected, unknown call a month you will almost always answer it. If you get three a day you will almost never answer it. We are allowing private businesses and scammers to steal the “commons” of our societal attention. We are doing a very poor job of keeping useful communications channels open: almost every communication medium people rely on for important information gets cluttered with must-ignore spam, making it decreasingly likely an important message is actually received.
- cozzyd 6y agoI imagine contact tracers would at least leave a voicemail? I always let numbers I don't recognize and aren't local (my cell phone number is out-of-state and spam calls usually originiate from that area code, not my current local) go to voicemail since I assume if they're important, they'll leave a voicemail.
- bluGill 6y agoI've got enough IRS and social security calls on my voice mail as to ignore them all too. If I don't know the voice and I'm not expected the call it is ignored.
- xav0989 6y agoThat only works if you have and check your voicemail. Many people either don't have a voicemail or don't bother ever setting it up. When the carriers start charging you a lot of money to have a voicemail, plenty of people will forgo it, and instead say things like "if it's important enough they'll call back" or "they'll send me a text message".
- logifail 6y ago> Many people either don't have a voicemail or don't bother ever setting it up. I actively turned my voicemail off completely. There is simply no-one who I want to talk to who would choose to leave me a voicemail if I don't answer.
- jhardy54 6y agoFWIW I get lots of spam voicemails, to the point where the 'new voicemail' notification doesn't glass any confidence that a human called me. I can, of course, listen to every voicemail, but that's not much better than just picking up the phone when I get a spam call.
- FalconSensei 6y agoI would say 95% of the voicemail is spam. The other 5% also sends me an email if they couldn't reach me. So basically the only reason I check my voicemail is to get rid of the notification on my phone
- borispavlovic 6y agodon't know about other countries but in Switzerland somehow people do not get the codes for Covid app with positive test results. even if they had the app installed and running the crucial step of entering the official code is failing
- gizmo 6y agoPeople are contagious a few days before they show symptoms, but most infections are by unambiguously symptomatic people, because they carry the highest viral load. If symptomatic people stay home you cut down infections by 2/3rd if not more. R0 goes from 1.5 to 0.5 and that's sufficient.
- Jommi 6y agohttps://www.news-medical.net/amp/news/20201005/Viral-loads-peak-before-symptom-onset-in-COVID-19.aspx https://www.news-medical.net/amp/news/20201005/Viral-loads-p... Viral Load Peaks before symptom offset.
- gizmo 6y agoThe work you cite is speculative. > Available evidence from contact tracing reported by countries suggests that asymptomatically infected individuals are much less likely to transmit the virus than those who develop symptoms. A subset of studies and data shared by some countries on detailed cluster investigations and contact tracing activities have reported that asymptomatically-infected individuals are much less likely to transmit the virus than those who develop symptoms. http://www.emro.who.int/health-topics/corona-virus/transmission-of-covid-19-by-asymptomatic-cases.html http://www.emro.who.int/health-topics/corona-virus/transmiss...
- mohammad_ali85 6y ago> No it wouldn't. One of the things that makes SARS-CoV-2 such a problem is that people get contagious long before they show symptoms. Similarly to for influenza and the common cold, many people get contagious without ever developing symptoms. Agree with the main thrust of the point but if everyone did stay home for 14 days you may well eradicate the virus. Problem of course that its economically/socially/medically impossible to facilitate a complete 14 day lockdown.
- mikem170 6y ago>if everyone did stay home for 14 days you may well eradicate the virus This would not be possible. There are at least several species of animals (mikes, civets, and bats) than can transmit this virus. We would need to quarantine and test, or kill, each and every one of these animals to be sure we eliminate this virus, or else it will eventually make its way back to humans. My opinion, based on what I read, is that this will be a bit of a scourge until such time as enough people have immunity from either catching it or getting vaccinated. Over time, as this new coronavirus makes its way through the human population, the experts it to become less virulent in general and/or appear less often. [0] [0] https://www.statnews.com/2020/02/04/two-scenarios-if-new-coronavirus-isnt-contained/ https://www.statnews.com/2020/02/04/two-scenarios-if-new-cor...
- Vrondi 6y agoAlso, cats and dogs can catch Covid-19. We think it's rare, but it is documented. https://www.cdc.gov/coronavirus/2019-ncov/daily-life-coping/pets.html https://www.cdc.gov/coronavirus/2019-ncov/daily-life-coping/...
- macintux 6y agoLatest headline I saw, didn’t read because I didn’t want to be depressed, was that asymptomatic carriers were shedding the virus for months.
- usrusr 6y agoAnother reason why that synchronous 14 day lockdown would fail to eradicate the virus: unless you are going for total solitary confinement, intra-family transmission chains would be able to sustain the virus much, much longer than those 14 days. Even a household as small as a two child nuclear family could sustain the virus quite long if each infection happens to have a fan-out of one and happens rather late in the contagiousness window.
- thu2111 6y agothat people get contagious long before they show symptoms I don't think that's correct. Pre-symptomatic phase is supposed to be about 2-3 days. I wouldn't describe that as 'long' before they show symptoms.
- ticmasta 6y agoif it's before though, then how would isolation after symptoms prevent the spread? I think the original post stand if perhaps overstated.
- alistairSH 6y agoNot symptoms, but positive test results... In the US, people are going to work (or other events) WITH positive test results. Some because they won't get paid otherwise, others because they want to make a political statement, and some because they're ... well, I dunno why... So, yes, even having people stay home after a positive test would be helpful, because currently, they aren't even doing that.
- sandworm101 6y agoI'll line up to get a vaccine because I trust in the scientific/medical community. I haven't installed my local contact-tracing app because ... 1) When I did try to install it said I need to update to a new OS, meaning my five year old phone likely wasn't good enough. 2) My local app doesn't provide alerts to me rather it alerts government contact tracers who today stated that they are only responding to alerts regarding medical/care home workers. I am neither. 3) My phone is not with me at work, the place where I interact with the most people by far, rendering the entire scheme basically useless. But yes, I would get a vaccine in a heartbeat.
- rehangs_plot 6y agoIt isn't a western thing. Less than half of Singaporeans installed their TraceTogether app[0]. [0] https://www.zdnet.com/article/less-than-half-in-singapore-willing-to-share-covid-19-results-with-contact-tracing-tech/ https://www.zdnet.com/article/less-than-half-in-singapore-wi...
- treeman79 6y agoWhy on earth would allow some government agency to track me. Some health departments have taken it upon themselves to arrest people that won’t sign documents. It’s like HOA battles, except now you can be put in jail on a whim. Even being an common case, and will likely be overturned in courts, it’s just too risky.
- Dylan16807 6y ago> Some health departments have taken it upon themselves to arrest people that won’t sign documents. Which health departments, what documents, and how many people? And how did they get arrest powers?
- wolco2 6y agoNever heard of this but I could see it happening. New Covid health task force under Biden gives an order.
- throwaway201103 6y agoHealth departments can order you to quarantine. In practical termss that's like house arrest.
- treeman79 6y agoNot like house arrest. But actual house arrest. Ankle monitors. http://www.wvih.com/wp1/index.php/2020/07/19/couple-on-house-arrest-for-not-signing-quarantine-form/ http://www.wvih.com/wp1/index.php/2020/07/19/couple-on-house...
- jscheel 6y agoOr, like me, your health department doesn't even bother to contact you. I had to do my own contact tracing when I tested positive.
- wolco2 6y agoHow is that possible? Did you call all of the places you were and got contact information from anyone in that area that day?
- usrusr 6y ago> One of the things that makes SARS-CoV-2 such a problem is that people get contagious long before they show symptoms. I also wonder how effective the vaccine is at preventing its receivers from even reaching that asymptomatic but already contagious stage. If "90%" is just "90% less reach symptomatic stage" then the percentage of receivers that are prevented from reaching contagiousness could be much lower. This would basically mean that the virus is almost guaranteed to become endemic despite vaccination (unless another vaccine also removes the contagious stage quite well) and that everyone who doesn't get a vaccine will eventually test their immune system against the virus. Natural immunity often follows a similar pattern. After a while you become susceptible to a light reinfection but the immune system will be in a very good position for a quick - but not instantaneous - victory on its second encounter with the virus. Under those circumstances, herd immunity effects fail to realize unless the first wave is so lightning fast that it fizzles out before the immune systems of early survivors (or the similarly vaccinated) fall back into standby mode.
- howlgarnish 6y agoContract tracing seems to work just fine in the Asian countries that have successfully stopped the virus in its tracks, and if China's 1.3 billion people isn't at scale, I'm not sure what is. But yes, it does require having few enough infected people to make it feasible, and places like the US and most of Europe are waaaaay beyond that point now.
- maxerickson 6y agoChina has also done mass testing when their contract tracing broke down. If we could get high compliance with isolation of positives, the US/Europe could use mass testing to "reset" without lockdowns. Test all of Michigan across a couple days and you will identify a significant portion of the infected. Then do Wisconsin. Encourage people to limit travel during those periods and so on. You wouldn't get to 0 in one cycle, but it would hammer the transmission rate.
- roywiggins 6y agoSlovakia has tried it: https://www.voanews.com/covid-19-pandemic/slovakias-second-round-coronavirus-tests-draws-large-crowds https://www.voanews.com/covid-19-pandemic/slovakias-second-r...
- rlt 6y ago> If we could get high compliance For better or worse [1], complying with mass government orders is simply not part of the collective American psyche. 1. it still remains to be seen if this individualism and distrust of government is one of America’s greatest strengths, or its future downfall
- maxerickson 6y agoYes, I phrased it that way quite on purpose. I'd prefer not to get Covid19, but the real worrying thing about it is the potential for a worse disease. Say it's almost as transmissible but much more deadly. How will we respond? I'm sure many people would do more to protect themselves, but I wonder how deadly it would have to be for some people, and how deadly would it have to be to make community minded cooperation the obvious path (this is a reasonable description of mask wearing…).
- TomVDB 6y ago“Anywhere” as in “the western world”? Because contact tracing seems to work very well at scale in Asia.
- ChrisMarshallNY 6y agoI would say most specifically in the US. It's a cultural thing. Asian cultures vary dramatically between each other (don't mistake Koreans, Chinese, or Japanese for each other -it won't end well), but they have one thing in common: They have a real sense of every person is part of a collective. Maybe it's because most Asian societies are quite crowded. The US, on the other hand, has a real sense of everyone is an individual, to the point of actually considering people that follow rules and norms to be "sheeple" (see "antimaskers"). Europeans seem to be in the middle.
- arethuza 6y agoIn the UK, and England specifically, another factor is ideology - vast amounts of money have been spent on outsourcing contact tracing even though the statistics suggest the result performance isn't very good. Meanwhile, local government run contact tracing has been really effective but seems to be starved of resources because they are public sector and therefore, apparently, must be bad at what they do.
- makomk 6y agoThose comparisons are misleaidng and themselves the result of ideology - the local contact tracing and national contact tracing have different success rates in large part because they handle different kinds of contacts. Local contact tracing handles "complex" cases, which are generally things like workplace outbreaks where they have the help of employee records and attendance lists. National contact tracing handles all the other, less robustly recorded social contacts. I believe that in Canada, where all contact tracing is local, a lot of areas have recently abandoned tracing the kinds of contacts that are handled by the UK's national scheme altogether because they don't have the resources and it doesn't work well.
- latchkey 6y agoContract tracing worked in Vietnam.
- seunosewa 6y agoContact tracing has been working in South Korea and many other countries from the beginning.
- Certhas 6y ago> Contract tracing hasn't worked at scale anywhere. I am not sure this is true. At least some articles I read attribute the successes in many Asian countries to aggressive contact tracing and quarantining. You don't ask people kindly to self-isolate, you move them to hotels and quarantine them. You don't ask them to remember their contacts, you aggressively investigate them using every source of data available. I think an argument can be made that Europe simply got it wrong in the details. In order to find less invasive means of controlling covid that respect privacy we ended up limiting freedoms much more and for longer.
- spullara 6y agoAsia results are from strict compliance to protocols across the population.
- lostlogin 6y ago> In order to find less invasive means of controlling covid that respect privacy we ended up limiting freedoms much more and for longer. There is limited freedom during a lockdown, but a short sharp one can lead to almost complete normality soon after. Short and sharp or long and drawn out? The drawn out option would seem a dubious freedom. My perspective is heavily skewed by being in NZ and reading US and UK news.
- josephg 6y agoYep. People seem to think that more lockdown = worse economy. NZ shows the relationship isn't so simple. A stricter lockdown seemed to work better from both a health perspective and an economic perspective.
- wolco2 6y agoAsian and Italian strain were different covid strains.
- wolco2 6y agohttps://news.ycombinator.com/item?id=25040098 https://news.ycombinator.com/item?id=25040098
- bbojan 6y agoContract tracing has worked at scale at South Korea for example.
- lostlogin 6y ago> Contract tracing hasn't worked at scale anywhere. Could you go a little deeper in this? It seems to have worked in Australia, South Korea and NZ as far as I’m aware, what am I missing?
- disgruntledphd2 6y agoAnd Japan. To be fair, Aus and NZ caught their epidemics very early, and are islands. Korea and Japan appear to have contained theirs through the use of reverse contact tracing. The big problem in the "West" (i.e. Europe and US) is that lots of people don't engage with the contact tracing system, which makes the epidemic almost impossible to control. Any amount of community transmission will eventually lead to an out of control epidemic, unfortunately.
- robocat 6y ago> Any amount of community transmission will eventually lead to an out of control epidemic, unfortunately. The countries mentioned have had community transmission, but they use contact tracing, testing, and shutdowns to stop it.
- Teever 6y agoI keep hearing the 'they are islands' thing and it has never made much sense to me. Can you explain why being an island is intrinsically better than not being an island? Does the size of the island matter? Does the location of the island matter? What if there are multiple islands?
- 867-5309 6y agoagreed. if anything, being an island would be worse because you have to condense a lot people into confined spaces just to cross the border
- corty 6y agoIslands don't really matter, but closed borders do. Europe has very different policies and rates of spread, but open borders mean that no country in the EU can eradicate Corona if the rest doesn't eradicate it at the same time. Case in point, Germany was at practically zero (around 1% positive tests with a 1% false positive rate) 6 weeks ago, currently it is lagging 3 weeks behind all its neighbors in the number of cases, rising exponentially.
- blago 6y ago> Contract tracing hasn't worked at scale anywhere. It's worked pretty well all over Asia.
- hcknwscommenter 6y ago"Covid19 would also be over if people with symptoms would just stay home." That is unlikely to be true. There are asymptomatic super spreaders. The fact that R0 is currently hovering around 1 is that society has greatly reduced contacts. Even in areas where social distancing is a mere suggestion, most people are not behaving completely normally (a good thing). Flights are super low, movie theater visits are super low, hotel occupancy is super low. Social distancing and contact tracing work. Better social distancing and contact tracing work better.
- WanderPanda 6y ago> Mutations aren't a serious concern. Because when viruses mutate it's the strains that are more infectious and less lethal that win out What if it has the contagiousness of covid but the long term lethality of hiv? The long term lethality would have low evolutionary pressure to be less harsh to its host as the implications only follow after many infectious years. Is there anything fundamentally prohibiting the emergence of such a virus, or are we just lucky?
- bigbubba 6y ago> What if it has the contagiousness of covid but the long term lethality of hiv? What if we get hit by a comet?
- WanderPanda 6y agoTo me it's not so obvious that the probabilities are that low, thats why I was asking
- Thiez 6y agoVirusses mutate all the time. What if a normal flu virus mutates and kills us all? There is no reason to believe that covid is more likely to become more lethal compared to any other type of virus.
- throwaway2245 6y agoExcept that contact tracing has worked at scale, in most countries of Asia, Africa and Australasia.
- fungiblecog 6y agoWhat you're describing is not a false positive as it is usually used. A false positive is a test that returns a positive result when the person does not actually have the virus. What you're describing is that most of the contacts return a negative test (and don't have the virus).
- samatman 6y ago> Mutations aren't a serious concern. Because when viruses mutate it's the strains that are more infectious and less lethal that win out. If only it worked that way! It doesn't, of course. A random walk can lead anywhere in the adjacent landscape. That includes moving up in lethality without moving down in infectiousness. What you have written here is plausible-sounding nonsense; if it were true, the 1918 flu would never have occurred. The good news is that influenza is almost pathologically mutation-prone, and coronaviruses are not.
- empthought 6y agoThank you for pointing this out.
- freewilly1040 6y agoThe oft-cited theory about 1918 is that WWI upended the traits that were selected for in the virus. Whereas in peace time a more serious case would reduce the mobility of the victim, in war a serious infection would result in the patient (a soldier) being transported off the front lines, spreading the more serious version of the virus more.
- sellyme 6y agoMoving up in lethality while maintaining the same "infectiousness" still results in a real-world decrease in infection rate, as more infected hosts will die (and/or infected hosts will die more quickly), preventing them from spreading it further.
- samatman 6y agoIn the case of COVID-19, which is highly contagious, has a long latency period, and is in fact not especially fatal by the standard of diseases ending in -RS, this might be true on paper, but would be cold comfort in practice.
- Taniwha 6y agoIt seems to be working here in New Zealand - we have an ongoing problem getting people to use the Covid app, but that just makes it easier, doesn't replace calling people on phones Of course it helps to get the actual rate so close to 0 that the contact tracers are not overloaded
- raducu 6y agoCovid would be over if everybody used a properly fitted respirator. I stayed at home even before symptoms, I infected 3 adults and my daughter in my house. It was only luck that the adults showed symptoms like myself on day 3 and day 3 was a Sunday and my test results came back that day. Otherwise, they woul have infected others just like I infected them, before I showed any symptoms.
- easytiger 6y ago> Covid would be over if everybody used a properly fitted respirator. AND gave up all human interaction. It is absurd to suggest that we should sacrifice civilisation for a virus
- __david__ 6y agoI'd happily give up all human interaction for a month or 2 if it meant that this annoyance wouldn't last an entire year like it has. Also, we _are_ sacrificing civilization for a virus. Or at least 1.2 million people's worth of civilization…
- easytiger 6y agoThat's a false bargin. People did similar universally do the above in many nations and it had little benefit. In turn they have lost and entire year. In turn that is the foundation of circular logic as above > Or at least 1.2 million people's worth of civilization… 1.x million natural deaths with an average age of 82 years old, in the UK.
- singingfish 6y agoContact tracing is working extremely well here in New South Wales. But we have very low incidence of virus in the community, sufficient to get useful early warnings when DNA analysis picks up virus in the sewage system. So once you're down to low levels of incidence in the community, given a robust well organised system, efficient contact tracing does prevent the virus from spreading in the community unchecked.
- hnick 6y agoReference if anyone cares: https://www.abc.net.au/news/2020-09-08/why-pm-says-nsw-is-gold-standard-in-covid-19-control/12636890 https://www.abc.net.au/news/2020-09-08/why-pm-says-nsw-is-go... They have done very good at tracking and locking down the few cases that get out, even with very low mask use in the general community based on what I've seen. People were sensible when it mattered most.
- f311a 6y agoIt worked in a few countries that now have close to zero cases.
- jariel 6y ago"Contract tracing hasn't worked at scale anywhere." It works 'at scale' in Taiwan/Korea if by 'scale' you mean 'large country' but yes, it does not work when there are many infected, it's best suited for when there only small numbers and the government can keep a lid on that. But that's entirely possible. Remember that countries have local agencies and national numbers are not everything. Ontario is only 12M people, British Coloumbia 5M people and they have active contact tracing of literally every patient. So with 90% effectiveness, the numbers will be brought way down, and in many areas, the threshold of cases will be low enough that contact tracing can be enacted. So about the 50 people - we have to basically still maintain a degree of isolation, and that's entirely possible. We don't need to tell the grocery store workers to 'self isolate' because someone came into the store with COVID that's already happening, those are low-risk events. During social isolation, people should absolutely not be contacting 50 people. So masks, basic social isolation at very least (no unnecessary contact) can remain in place.
- JSavageOne 6y ago> Contract tracing hasn't worked at scale anywhere. It's worked in South Korea
- hndamien 6y agoIt's worked in Australia.
- heavyset_go 6y agoIt worked really, really well in South Korea and New Zealand. Besides, that's just your opinion and epidemiologists agree that contract tracing plays a significant role in reducing the spread of COVID.
- virgilp 6y agoIt's different now - because of the strict quarantine requests, coupled with the knowledge that there's no known treatment/vaccine, coupled with the fact that you have literally tens of thousands of cases per day - means that people don't cooperate that much, and the system is already over-stretched. Also, "hasn't worked at scale anywhere is false" - AFAIK it worked fairly well in South Korea, Japan, New Zeeland, China.
- Gravityloss 6y agoSo how is the corona situation currently in South Korea?
- bufferoverflow 6y ago> Contract tracing hasn't worked at scale anywhere In South Korea it did. They now have very few cases and deaths in single digits per day.