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If you want to be incredibly angry at the ineffectiveness of the current testing regime that we as a country are heavily investing in, listen to this episode of

by birken 6y ago

If you want to be incredibly angry at the ineffectiveness of the current testing regime that we as a country are heavily investing in, listen to this episode of the This Week In Virology podcast: https://www.microbe.tv/twiv/twiv-640/ https://www.microbe.tv/twiv/twiv-640/ [TWiV 640: Test often, fast turnaround, with Michael Mina] The way to beat the pandemic is to have cheap, disposable instant tests that anybody can take in their homes, everyday, to see if they have a large amount of virus in their system. These instant tests will not have the sensitivity or specificity of the PCR style test, but it doesn't matter. The PCR style test can test for levels of virus that are billions or trillions times smaller than necessary, yet we disqualify other types of tests because they aren't as accurate as the PCR tests. So we set an impossible standard that all other tests, no matter how practically useful they could be, fail to reach. We all could have cheap, accurate enough instant tests, but do not because they aren't as accurate as a test that is ridiculously accurate but takes so long to get results at scale it becomes completely ineffective. It's complete madness.

jacquesm 6y ago
Is there such a thing as an instant test on the market?
- microcolonel 6y ago
  A company here in Canada tried to bring one to market, but I think it was completely disapproved because it was not precise and specific enough, which baffled me since I don't really see the downside of it being available even if that's the case. Yes, accuracy is a nice thing to have, but if you aren't tested at all you are worse off. You can still follow precautions if you are negative on an inaccurate test, but we can't afford to have everyone take the precautions that those with positive tests should. If the test is highly sensitive but biased toward false positives, that would also be a useful form of test.
  - jacquesm 6y ago
    That it will lead to a lot of follow up tests and people that are ill thinking they are not.
    - birken 6y ago
      My understanding of the tests is they are very accurate at determining if somebody has a lot of virus, but not at detecting lower thresholds of virus. So compared to PCR tests, they have a lot of false negatives. The Abbott ID NOW COVID-19 rapid result machine that the white house uses has the same properties: > Based on our findings we could argue that the Abbott ID NOW detects samples with high viral load or possibly viable virus that could be of importance for transmission. But, the fact that it misses positive samples on patients being admitted to the hospital with clinical picture of COVID-19 makes this technology unacceptable in our clinical setting [1] So they will have very few false positives, but a lot of false negatives. However... being negative for having a lot of virus is actually meaningful, whether you have the virus or not, because the best assumption is that contagiousness is related to amount of virus in your system. So basically, the tests aren't perfectly accurate, but they do provide useful information, and they are instant. That is the key. A PCR test that is perfectly accurately is useless for contact tracing/isolation and peace of mind if it takes 14+ days to get the results. Think of a pregnancy test. If it comes back positive, you are very likely pregnant but should get it confirmed by a doctor. If it comes back negative, you likely aren't pregnant, but maybe it's too early to tell. Pregnancy tests are widely used even though they have these characteristics because people understand the quirks and the information they provide is useful and of course, comes instantly. 1: https://www.biorxiv.org/content/10.1101/2020.05.11.089896v1.full https://www.biorxiv.org/content/10.1101/2020.05.11.089896v1....
  - contravariant 6y ago
    If it's not specific enough a significant portion of the population will have to go into quarantine for no obvious reason, and if it's no precise enough you either need to keep the restrictions or let a significant portion of the infected population move around with no precautions whatsoever. I'm not sure why you're not seeing any problems with this.
    - phendrenad2 6y ago
      It doesn't have to lead to quarantine. Many people are running around acting as though the virus is gone. Some are staying indoors with a cold thinking they might have the virus. If they could self-test and make their own decision about the risk of changing their behavior, it would help immensely.
  - ttul 6y ago
    Listen to the TWiV episode. The idea behind the cheap test is that it picks up COVID at maybe a billion times greater viral load than an RT-PCR test would. If a billion sounds like a lot, it’s not. The virus goes from undetectable to rampant within hours. The cheap test will miss out the very early stage of infection. But we are talking hours. Such a cheap test could allow kids to go to school or adults to go to work. It would be revolutionary.
m0zg 6y ago
That's like saying "the way to beat poverty is for everyone to have a billion dollars". Both true and impossible at the same time. At least impossible outside Zimbabwe, that is.
- quickthrower2 6y ago
  Yes but can we easily afford a pandemic that goes on for years? Interesting you mention Zimbabwe, do we print money to help those out of work due to this?
  - m0zg 6y ago
    But it will "go on for years" no matter what we do. The virus is endemic now.
    - quickthrower2 6y ago
      There is a difference between occasional outbreaks and perpetual death tolls, even if technically the virus is still about in both cases
      - m0zg 6y ago
        Sooner or later you have to open the borders and restart economies. After doing which you get unlimited rides on this pony.
        quickthrower2 6y ago
        Maybe you don't have to open the borders. We can have a functional economy without the average person getting in planes and moving around the world. It is enough for essential staff and cargo to move around the world. No reason why that shouldn't work and we can't all make money. We will just be making money doing different things in different ways with different norms. Mother's day? Restaurant? Nah. What should we order from uber eats? Who delivers flowers. Etc. Gap year? Let's travel in the same country / same state, and go deeper rather than wider.
latchkey 6y ago
Ok, so you get the accurate inexpensive fast test... then aren't you still hostage to the least compliant person?

by birken 6y ago

jacquesm 6y ago

Is there such a thing as an instant test on the market?

microcolonel 6y ago
A company here in Canada tried to bring one to market, but I think it was completely disapproved because it was not precise and specific enough, which baffled me since I don't really see the downside of it being available even if that's the case. Yes, accuracy is a nice thing to have, but if you aren't tested at all you are worse off. You can still follow precautions if you are negative on an inaccurate test, but we can't afford to have everyone take the precautions that those with positive tests should. If the test is highly sensitive but biased toward false positives, that would also be a useful form of test.
- jacquesm 6y ago
  That it will lead to a lot of follow up tests and people that are ill thinking they are not.
  - birken 6y ago
    My understanding of the tests is they are very accurate at determining if somebody has a lot of virus, but not at detecting lower thresholds of virus. So compared to PCR tests, they have a lot of false negatives. The Abbott ID NOW COVID-19 rapid result machine that the white house uses has the same properties: > Based on our findings we could argue that the Abbott ID NOW detects samples with high viral load or possibly viable virus that could be of importance for transmission. But, the fact that it misses positive samples on patients being admitted to the hospital with clinical picture of COVID-19 makes this technology unacceptable in our clinical setting [1] So they will have very few false positives, but a lot of false negatives. However... being negative for having a lot of virus is actually meaningful, whether you have the virus or not, because the best assumption is that contagiousness is related to amount of virus in your system. So basically, the tests aren't perfectly accurate, but they do provide useful information, and they are instant. That is the key. A PCR test that is perfectly accurately is useless for contact tracing/isolation and peace of mind if it takes 14+ days to get the results. Think of a pregnancy test. If it comes back positive, you are very likely pregnant but should get it confirmed by a doctor. If it comes back negative, you likely aren't pregnant, but maybe it's too early to tell. Pregnancy tests are widely used even though they have these characteristics because people understand the quirks and the information they provide is useful and of course, comes instantly. 1: https://www.biorxiv.org/content/10.1101/2020.05.11.089896v1.full https://www.biorxiv.org/content/10.1101/2020.05.11.089896v1....
- contravariant 6y ago
  If it's not specific enough a significant portion of the population will have to go into quarantine for no obvious reason, and if it's no precise enough you either need to keep the restrictions or let a significant portion of the infected population move around with no precautions whatsoever. I'm not sure why you're not seeing any problems with this.
  - phendrenad2 6y ago
    It doesn't have to lead to quarantine. Many people are running around acting as though the virus is gone. Some are staying indoors with a cold thinking they might have the virus. If they could self-test and make their own decision about the risk of changing their behavior, it would help immensely.
- ttul 6y ago
  Listen to the TWiV episode. The idea behind the cheap test is that it picks up COVID at maybe a billion times greater viral load than an RT-PCR test would. If a billion sounds like a lot, it’s not. The virus goes from undetectable to rampant within hours. The cheap test will miss out the very early stage of infection. But we are talking hours. Such a cheap test could allow kids to go to school or adults to go to work. It would be revolutionary.

m0zg 6y ago

That's like saying "the way to beat poverty is for everyone to have a billion dollars". Both true and impossible at the same time. At least impossible outside Zimbabwe, that is.

quickthrower2 6y ago
Yes but can we easily afford a pandemic that goes on for years? Interesting you mention Zimbabwe, do we print money to help those out of work due to this?
- m0zg 6y ago
  But it will "go on for years" no matter what we do. The virus is endemic now.
  - quickthrower2 6y ago
    There is a difference between occasional outbreaks and perpetual death tolls, even if technically the virus is still about in both cases
    - m0zg 6y ago
      Sooner or later you have to open the borders and restart economies. After doing which you get unlimited rides on this pony.
      - quickthrower2 6y ago
        Maybe you don't have to open the borders. We can have a functional economy without the average person getting in planes and moving around the world. It is enough for essential staff and cargo to move around the world. No reason why that shouldn't work and we can't all make money. We will just be making money doing different things in different ways with different norms. Mother's day? Restaurant? Nah. What should we order from uber eats? Who delivers flowers. Etc. Gap year? Let's travel in the same country / same state, and go deeper rather than wider.

latchkey 6y ago

Ok, so you get the accurate inexpensive fast test... then aren't you still hostage to the least compliant person?