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Faa recommends Covid testing for crew

Old 03-05-2021, 03:19 PM
  #31  
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Originally Posted by ugleeual View Post
China style anal swabs at KCM?
Sure, and the current Administration has a good working relationship with China, so they can probably hire some experts for relatively low cost to administer the plan.


The point is, the only reason to test flight crews is purely political, just like the Chinese test.

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Old 03-05-2021, 03:24 PM
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Originally Posted by highfarfast View Post
It seems kinda late in the game for this kind of measure.
Considering we will have vaccines available for everyone who wants one in the US within months, and thereby herd immunity, you are correct. We should be switching our focus from test/tracking/tracing to vaccination access (and education for the idiots that are still reluctant.)
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Old 03-05-2021, 04:53 PM
  #33  
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Originally Posted by Minepza View Post
From Harvard health below it says positive tests are almost always correct. Negative tests may be less definitive. I guess what I’m asking is if it’s known that the accuracy is near 100% meaning 85% or more, why assume that none of it works. Let’s be realistic, the chance of you driving up to a test site and knowing if you have it or not is very good. Everyone I know including me that has tested can agree with this.


https://www.health.harvard.edu/disea...he-coronavirus


How reliable are the tests for COVID-19?

Two types of diagnostic tests are currently available in the US. PCR tests detect viral RNA. Antigen tests, also called rapid diagnostic tests, detect specific proteins on the surface of the coronavirus. Antigen test results may come back in as little as 15 to 45 minutes; you may wait several days or longer for PCR test results.

The accuracy of any diagnostic test depends on many factors, including whether the sample was collected properly. For PCR tests, which are typically analyzed in a laboratory, test results may be affected by the conditions in which the test was shipped to the laboratory.

Results may also be affected by the timing of the test. For example, if you are tested on the day you were infected, your test result is almost guaranteed to come back negative, because there are not yet enough viral particles in your nose or saliva to detect. The chance of getting a false negative test result decreases if you are tested a few days after you were infected, or a few days after you develop symptoms.

Generally speaking, if a test result comes back positive, it is almost certain that the person is infected.

A negative test result is less definite. There is a higher chance of false negatives with antigen tests. If you have a negative result on an antigen test, your doctor may order a PCR test to confirm the result.

If you experience COVID-like symptoms and get a negative PCR test result, there is no reason to repeat the test unless your symptoms get worse. If your symptoms do worsen, call your doctor or local or state healthcare department for guidance on further testing. You should also self-isolate at home. Wear a mask when interacting with members of your household. And practice physical distancing.
I take it you lack either the desire or the intellect to understand Bayes Law as it applies to clinical testing. positive results are NOT “almost always correct” and false positives are not “rare”. Moreover, “rare’ is an undefined arithmetic expression, and represents little more than someone’s subject impression.

A year ago we were told that the mutation rate for COVID was “low” so the likelihood of unfavorable mutant strains was “low.” Except there is and was nothing inherently “low” in the mutation rate EXCEPT in comparison to other viruses. But mutation rate is not the determining factor, it’s that rate TIMES THE OPPORTUNITIES TO MUTATE and every single case of COVID involves millions, billions, whole friggin Avogadro’s numbers of opportunity to mutate, and “low” multiplied by a $hittonfull was enough to produce a number of interesting mutant strains that are worrying us now.

Since you are either unwilling to read the ample literature (or view the video) on Baye’s theorem, or comprehend the same, we’ll do it the Baye’s Theorem for Idiots way, which if not totally correct will at least convey the flavor. Let us consider two groups of a million people. One group has a 5% rate of infectious COVID, the other a 0.5% rate of infectious COVID.

let us use a PCR test that has a sensitivity of 99.9% (which is higher than anybody really claims, especially early in the course of the disease when people are only recently infected). Let us say the PCR test has a specificity of 99%, which is FAR higher than PCR tests have.

Sensitivity (True Positive rate) measures the proportion of positives that are correctly identified (i.e. the proportion of those who have some condition (affected) who are correctly identified as having the condition.

Specificity measures a test's ability to correctly generate a negative result for people who don't have the condition that's being tested for (also known as the “true negative” rate).

OK, now let’s test those two million-person groups.

The 5% group will have 50,000 people who are true positives. The 99.9% sensitivity test will detect 49,500 of them, missing a mere 500. I guess 1 in 200 doesn’t sound bad, but look at the flip side. The 99% specificity means that of the 950,000 people that DON’T have COVID, the test will erroneously identify 950 of them as having COVID. So at a 5% prevalence rate the predictive value of a positive is 49,500/(49,500 + 950) or approximately 98%. Two out of a hundred are going to be false positives.

But now look at group two.
Only 0.5% of that group have COVID. That means that only 5000 of them have the disease. The test again detects 99.9% which is 4995 true positives and misses 5 true positives. It erroneously categorizes 1% of the 995,000 people who DON’t HAVE disease as positive meaning the predictive value of a positive has now declined to 4995/ (4995+ 9,950) or roughly .33.

Two out of three of your tests are going to be false positives.

now this was for illustration. The sensitivity and specificity of these clinical tests do not approach 99.9 or .99 (see below)






and in the population you are proposing to screen, the prevalence of what you are looking for - EARLY ASYMPTOMATIC CASES, is nowhere near 0.5%, far less 5%. One cannot make claims of “rare” in the absence of the population prevalence of the population being tested.

so in short, you are WRONG. I can explain it to you but I can’t understand it for you and if you are not going to take the effort to really research it you’ll just have to remain ignorant and no amount of posting info YOU clearly don’t understand - by either you or me - is going to change that.

Last edited by Excargodog; 03-05-2021 at 05:04 PM.
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Old 03-05-2021, 05:02 PM
  #34  
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You Tube has dozens of Bayes videos, watch them.
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Old 03-05-2021, 05:19 PM
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Originally Posted by GogglesPisano View Post
Considering we will have vaccines available for everyone who wants one in the US within months, and thereby herd immunity, you are correct. We should be switching our focus from test/tracking/tracing to vaccination access (and education for the idiots that are still reluctant.)
Yea, are you sure that you aren’t the idiot though?

Funny, the more “education” I hear from greedy big pharma, the more I resent anything they lay their greedy pig hands on. Also, parading politicians and celebrities to try to persuade people to take the vax is the creepiest **** I’ve ever seen. Borderline soviet style propaganda.
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Old 03-05-2021, 06:13 PM
  #36  
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Originally Posted by GogglesPisano View Post
Considering we will have vaccines available for everyone who wants one in the US within months, and thereby herd immunity, you are correct. We should be switching our focus from test/tracking/tracing to vaccination access (and education for the idiots that are still reluctant.)
And this is what I meant. By the time they could get an en mass policy set up and everyone on board, nearly every crewmember that wants a vaccine will have had one... or at least so close to that point that I can't imagine there being a worthwhile benefit. 9 months ago? Maybe. Now? No way.
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Old 03-05-2021, 06:26 PM
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Originally Posted by highfarfast View Post
And this is what I meant. By the time they could get an en mass policy set up and everyone on board, nearly every crewmember that wants a vaccine will have had one... or at least so close to that point that I can't imagine there being a worthwhile benefit. 9 months ago? Maybe. Now? No way.
They will start testing of crews, and allow people that have been vaccinated to skip the testing process. It’s called coercion. Scumbags operate this way. All it does is turn more people away from taking the vaccine that might have considered it even a little bit.
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Old 03-05-2021, 09:01 PM
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Originally Posted by Excargodog View Post
I take it you lack either the desire or the intellect to understand Bayes Law as it applies to clinical testing. positive results are NOT “almost always correct” and false positives are not “rare”. Moreover, “rare’ is an undefined arithmetic expression, and represents little more than someone’s subject impression.

A year ago we were told that the mutation rate for COVID was “low” so the likelihood of unfavorable mutant strains was “low.” Except there is and was nothing inherently “low” in the mutation rate EXCEPT in comparison to other viruses. But mutation rate is not the determining factor, it’s that rate TIMES THE OPPORTUNITIES TO MUTATE and every single case of COVID involves millions, billions, whole friggin Avogadro’s numbers of opportunity to mutate, and “low” multiplied by a $hittonfull was enough to produce a number of interesting mutant strains that are worrying us now.

Since you are either unwilling to read the ample literature (or view the video) on Baye’s theorem, or comprehend the same, we’ll do it the Baye’s Theorem for Idiots way, which if not totally correct will at least convey the flavor. Let us consider two groups of a million people. One group has a 5% rate of infectious COVID, the other a 0.5% rate of infectious COVID.

let us use a PCR test that has a sensitivity of 99.9% (which is higher than anybody really claims, especially early in the course of the disease when people are only recently infected). Let us say the PCR test has a specificity of 99%, which is FAR higher than PCR tests have.







OK, now let’s test those two million-person groups.

The 5% group will have 50,000 people who are true positives. The 99.9% sensitivity test will detect 49,500 of them, missing a mere 500. I guess 1 in 200 doesn’t sound bad, but look at the flip side. The 99% specificity means that of the 950,000 people that DON’T have COVID, the test will erroneously identify 950 of them as having COVID. So at a 5% prevalence rate the predictive value of a positive is 49,500/(49,500 + 950) or approximately 98%. Two out of a hundred are going to be false positives.

But now look at group two.
Only 0.5% of that group have COVID. That means that only 5000 of them have the disease. The test again detects 99.9% which is 4995 true positives and misses 5 true positives. It erroneously categorizes 1% of the 995,000 people who DON’t HAVE disease as positive meaning the predictive value of a positive has now declined to 4995/ (4995+ 9,950) or roughly .33.

Two out of three of your tests are going to be false positives.

now this was for illustration. The sensitivity and specificity of these clinical tests do not approach 99.9 or .99 (see below)






and in the population you are proposing to screen, the prevalence of what you are looking for - EARLY ASYMPTOMATIC CASES, is nowhere near 0.5%, far less 5%. One cannot make claims of “rare” in the absence of the population prevalence of the population being tested.

so in short, you are WRONG. I can explain it to you but I can’t understand it for you and if you are not going to take the effort to really research it you’ll just have to remain ignorant and no amount of posting info YOU clearly don’t understand - by either you or me - is going to change that.

I don’t understand why you are talking about theories and statistics, and insulting me on it too, I didn’t even challenge you on that. I’m talking about a real practical world scenario of testing someone. People have been testing now since the beginning of the pandemic, it’s the way we know if we’re positive or not. You do understand this correct, that this is not in dispute? The majority of them get the correct result, especially if it’s positive, which is what we care about. You don’t have to even read a Harvard article to know this if you have been tested or know anyone that’s been testing. Just because one person gets a wrong result does not negate the 99% of the others that had it right. My original question was why wouldn’t you want to know if your fellow crewmember is infected?
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Old 03-05-2021, 09:36 PM
  #39  
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Originally Posted by Minepza View Post
I don’t understand why you are talking about theories and statistics, and insulting me on it too, I didn’t even challenge you on that. I’m talking about a real practical world scenario of testing someone. People have been testing now since the beginning of the pandemic, it’s the way we know if we’re positive or not. You do understand this correct, that this is not in dispute? The majority of them get the correct result, especially if it’s positive, which is what we care about. You don’t have to even read a Harvard article to know this if you have been tested or know anyone that’s been testing. Just because one person gets a wrong result does not negate the 99% of the others that had it right. My original question was why wouldn’t you want to know if your fellow crewmember is infected?
This is not about testing people who one has a clinical suspicion of illness, it is about random testing of EVERYBODY in the forlorn hope that it will give you meaningful information about their potential to affect others, with a test that is MATHEMATICALLY INCAPABLE of providing you with that information. By no stretch of the imagination are 99% of those tests going to be right. I would LOVE to know who is contagious and who is not but your proposed course of action would not provide that information.

Look, I give up. I have told you what you need to do to have a meaningful understanding of this issue, others have referred you to videos that fully explain it. As I said, I can explain it to you or point you to sources that will explain it to you but I can’t understand it for you. And you obviously never went to those sources or put any effort into understanding them. You are simply ignorant - which as I said is OK, it is clearly not an area where you have studied or likely ever needed, there is a lot of info in this world and none of us have all of it, but you not only persist in your ignorance despite people far more knowledgeable than you pointing to how you can educate yourself, but continue to arrogantly lecture to people who clearly comprehend the issue far better than you, and you are simply wrong. If you are comfortable with that and don’t care about being ignorant, so be it. Don’t look up Baye’s Theorem and see how it applies. Revel in your ignorance for all I care. But don’t pretend you know enough to correct people who do understand the issue. You are simply embarrassing yourself further.
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Old 03-06-2021, 12:33 AM
  #40  
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Originally Posted by Grumpyaviator View Post
CDC has no idea about virology and FAA have no idea about our work environment.
FIFY..........
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