This was covered about a month ago in episode 595 of This Week in Virology [1], in answer to a listener question: Rich Condit: Garrett writes: The CDC guidelines are to test hospitalized patients and symptomatic health care workers first, and the symptomatic general public last. This seems backwards to me. Alan Dove: Yeah. I just had this conversation with my wife after she had some, I mentioned this before, she had…
We’re Testing the Wrong People
51–60 of 155 posts
Re: We’re Testing the Wrong People
#52But the tests aren't perfect, so how to get actionable data from them isn't clear. We saw this with the flawed west coast studies. If a test has false positive or false negative rates even as high as 1%, and we run hundreds of thousands to millions of tests per day...that's thousands or tens of thousands wrongly quarantined for 14 days, and the same number who are contagious but told it's okay to go out.
We are currently quarantining about 300 million here in the US, so tens of thousands would be a massive improvement. The way to think about this is: who do we need to test so we can start un -quarantining people. The goal is not to find out who has it because right now, we are essentially behaving as if the entire US population is infected. The goal is to efficiently determine who is very unlikely to have it so that…
Re: We’re Testing the Wrong People
#53I've been saying this since the beginning of this whole thing. I don't understand why we haven't focused all of our testing on people that aren't sick so we can catch the asymptomatic cases that are out in the world spreading it to everyone.
Because we don't have enough tests. We could reopen the country if we could test enough people, but we're stuck. Even in New York and New Jersey, tests are still limited to symptomatic people because there isn't enough testing capacity.
Re: We’re Testing the Wrong People
#54This seems to ignore the importance of testing symptomatic people to rule out COVID (the most common outcome) so care givers can stop wasting PPE (which is is short supply).
Non-covid diseases still require the use of PPE. Also, PPE is much easier to produce than tests.
The PPE required for some COVID-19 symptoms in the absence of clear indication of a droplet/airborne transmissible condition are different than for COVID-19. You don't usually use droplet, much less airborne, protections for every patient presenting with a fever, or GI symptoms, or several of the other ways COVID-19 can present, but you must with the prevalence of COVID-19 until you can rule it out.
And it's even more critical to identify COVID-19 or it's absence in sick patients when part of your containment strategy involves segregating ftreatment facilities (part of the capacity surge has been in establishing either new COVID-19 specific facilities or new facilities to handle non-COVID-19 cases while existing capacity is dedicated to COVID-19.)
Re: We’re Testing the Wrong People
#55Earlier quoted context omitted.
The only thing stopping states from deficit spending (selling bonds to pay for general obligations) are the states’ own rules. As we have seen, constitutional requirements are not an impediment in a pandemic.
Which constitutional requirements do you think are being violated? And if you're going to say first amendment, be sure to explain precisely why they wouldn't survive strict scrutiny. (And if you're not aware of the legal meaning of "strict scrutiny," then you are probably ignorant of what the Constitution has actually been held to mean by the authority that has the power to interpret it.)
Re: We’re Testing the Wrong People
#56But the HN title is actionable: if we can change our testing policy and deploy our tests more usefully, that's great to know and eminently achievable.
But "not testing enough" isn't really actionable. There's a shortage of tests because there's a shortage of the raw materials that goes into making the tests. The U.S. already has tested far and away more people than anyone else, and is second only behind Italy in tests per capita, and has a "positive test to test" rate roughly in line with (as low of a rate as) any other country's rate. See [0] and related charts.
"Just test more" isn't really useful at this point.
[0] https://ourworldindata.org/grapher/full-list-total-tests-for...
Re: We’re Testing the Wrong People
#57Maybe someone here can explain to me how this is supposed to work. Let's assume we have enough tests in the US to test every single person in the country every 3 days, and are contact tracing everyone with a smartphone, and providing smartphones to everyone without. Now, with all this in place, isn't the best we can do to alert people after they have already been exposed to the virus? It feels a bit like the safe sex…
The target is to ensure that each case infects no more than one additional person (‘R Each infected person will come into contact with some other people. Testing allows three things— - first, we can tell this person to stay at home and so stop them from infecting more people; - second, we can tell the people they have seen to stay at home with good contact-tracing, so that even if they get it they don’t spread it fur…
Re: We’re Testing the Wrong People
#58I've been saying this since the beginning of this whole thing. I don't understand why we haven't focused all of our testing on people that aren't sick so we can catch the asymptomatic cases that are out in the world spreading it to everyone.
Because we don't have enough tests. We could reopen the country if we could test enough people, but we're stuck. Even in New York and New Jersey, tests are still limited to symptomatic people because there isn't enough testing capacity.
We don't treat Covid patients any differently than any other patients that develop pneumonia
Re: We’re Testing the Wrong People
#59This seems to ignore the importance of testing symptomatic people to rule out COVID (the most common outcome) so care givers can stop wasting PPE (which is is short supply).
During a pandemic, it's more likely than not that any negative test on a symptomatic person is false. It's also quite likely that a positive test on an asymptomatic person is also false -- depending on how prevalent it is in the general population.
I don't think we've reached the point where COVID-19 is the leading cause of fever, much less GI symptoms, so unless you define “symptomatic” extremely narrowly (like, “in need of a ventilator”) that's probably not true in this pandemic at this time in the US.
Re: We’re Testing the Wrong People
#60sampling bias debate reminds me of this stats legend from ww2: the USAF wanted to armor planes where the bullet holes were. statistician abe wald recommended armoring where the bullet holes weren't on the theory that those were the non-survivable hits can't interpret a statistic until you think about what's excluded from the sample
It certainly makes for a good drama though.