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The dichotomy isn't between the app or a medical professional guessing, based on contacts, whether someone might be infected and whether they should self-quaran

by mellow2020 6y ago

The dichotomy isn't between the app or a medical professional guessing, based on contacts, whether someone might be infected and whether they should self-quarantine. The dichotomy is between guessing infection based on contacts and testing for infection.

pimterry 6y ago
There isn't a dichotomy. We can use all these techniques. Testing is great of course, but given that you can't test everybody every day, testing is more effective when you can test the right people. If we can trace contacts, we can prioritize testing of people who've had a possible contact recently, and thereby find and quarantine infectious people faster.
- mellow2020 6y ago
  > There isn't a dichotomy. I simply meant that this "without ubiquitous, cheap, fast, and accurate testing, you can't confirm the app's diagnosis. So the alert is useless." was turned into medical professionals asking someone about contacts, a la "Someone you report you had coffee with, but who doesn't get the disease, is a false positive" to show that getting asked about contacts by medical professionals isn't better than a contact tracing app, which is a straw man, i.e. Schneier didn't ask for medical professionals to ask those questions, he said those questions are useless without tests.
  - nshepperd 6y ago
    He did ask for that, at the end of his post: > It has nothing to do with privacy concerns. The idea that contact tracing can be done with an app, and not human health professionals, is just plain dumb. Human health professionals doing contact tracing means exactly that.
    - mellow2020 6y ago
      In context, given all he wrote before, it's obvious that he means testing, not asking questions about who someone had coffee with.
      - sanderjd 6y ago
        No not at all, in that sentence he is talking about human health professionals doing contact tracing rather than apps. Which is why the thread-starter is right that his argument here is silly. It would be better for him to be clear-eyed that he is biased against technological contact-tracing solutions in favor of human ones, because of his privacy concerns. That is a totally reasonable position! What is not reasonable is arguing against using technology for contact tracing because it has false-positive and false-negative problems; it's true that it does, but all contact tracing solutions are probabilistic in this way.
feral 6y ago
You may be misunderstanding the purpose of contact tracing? It's not to guess whether a patient you have is infected. It is to find the people that patient has infected before those infect more people. If things are being run properly: 1. Someone shows up with the disease. (Tests positive, or clinical.) 2. You find their contacts, either by app or interview or both. 3. You tell those contacts to quarantine, hopefully before they've become infectious, breaking onward spread. 4. If they test negative and don't display symptoms, they stop quarantine. Unless you mean to test everyone every day? Sounds good, but then you need way more tests than countries have been able to make so far, and they have to be very sensitive and specific too, even before someone is infectious.
- yummybear 6y ago
  Regarding 3) - should they quarantine regardless or just if the get ill?
  - enitihas 6y ago
    They should quarantine regardless, since asymptomatic people are also spreaders. Ill people sre anyways getting quarantined even without any tracing.
  - chosenbreed37 6y ago
    > Regarding 3) - should they quarantine regardless or just if the get ill? I guess they have to quarantine. Not only them but anybody else that came into contact with and so and so forth :-)
  - feral 6y ago
    Probably. I would say that depends on the overall strategy. If pre-symptomatic people infecting others is a big issue, then it's probably worth the cost of quarantining folks who display no symptoms until you are sure they aren't sick. Obviously that means you quarantine a lot of people who don't later get sick. That sounds draconian, but its a lot better than lockdowns.
  - fragmede 6y ago

pimterry 6y ago

There isn't a dichotomy. We can use all these techniques. Testing is great of course, but given that you can't test everybody every day, testing is more effective when you can test the right people. If we can trace contacts, we can prioritize testing of people who've had a possible contact recently, and thereby find and quarantine infectious people faster.

mellow2020 6y ago
> There isn't a dichotomy. I simply meant that this "without ubiquitous, cheap, fast, and accurate testing, you can't confirm the app's diagnosis. So the alert is useless." was turned into medical professionals asking someone about contacts, a la "Someone you report you had coffee with, but who doesn't get the disease, is a false positive" to show that getting asked about contacts by medical professionals isn't better than a contact tracing app, which is a straw man, i.e. Schneier didn't ask for medical professionals to ask those questions, he said those questions are useless without tests.
- nshepperd 6y ago
  He did ask for that, at the end of his post: > It has nothing to do with privacy concerns. The idea that contact tracing can be done with an app, and not human health professionals, is just plain dumb. Human health professionals doing contact tracing means exactly that.
  - mellow2020 6y ago
    In context, given all he wrote before, it's obvious that he means testing, not asking questions about who someone had coffee with.
    - sanderjd 6y ago
      No not at all, in that sentence he is talking about human health professionals doing contact tracing rather than apps. Which is why the thread-starter is right that his argument here is silly. It would be better for him to be clear-eyed that he is biased against technological contact-tracing solutions in favor of human ones, because of his privacy concerns. That is a totally reasonable position! What is not reasonable is arguing against using technology for contact tracing because it has false-positive and false-negative problems; it's true that it does, but all contact tracing solutions are probabilistic in this way.

feral 6y ago

You may be misunderstanding the purpose of contact tracing? It's not to guess whether a patient you have is infected. It is to find the people that patient has infected before those infect more people. If things are being run properly: 1. Someone shows up with the disease. (Tests positive, or clinical.) 2. You find their contacts, either by app or interview or both. 3. You tell those contacts to quarantine, hopefully before they've become infectious, breaking onward spread. 4. If they test negative and don't display symptoms, they stop quarantine. Unless you mean to test everyone every day? Sounds good, but then you need way more tests than countries have been able to make so far, and they have to be very sensitive and specific too, even before someone is infectious.

yummybear 6y ago
Regarding 3) - should they quarantine regardless or just if the get ill?
- enitihas 6y ago
  They should quarantine regardless, since asymptomatic people are also spreaders. Ill people sre anyways getting quarantined even without any tracing.
- chosenbreed37 6y ago
  > Regarding 3) - should they quarantine regardless or just if the get ill? I guess they have to quarantine. Not only them but anybody else that came into contact with and so and so forth :-)
- feral 6y ago
  Probably. I would say that depends on the overall strategy. If pre-symptomatic people infecting others is a big issue, then it's probably worth the cost of quarantining folks who display no symptoms until you are sure they aren't sick. Obviously that means you quarantine a lot of people who don't later get sick. That sounds draconian, but its a lot better than lockdowns.
- fragmede 6y ago