Coronavirus

Inspector_50

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50% Accurate. Interesting.

Define that. Is it that 50% of the tests are WRONG one way or they other OR that there are MASS false positives to the order of 50%?

If the test was releasing 50% of those tested back into the population with false negatives there would be massive spread.

If the test was indication false positives 50% of teh time teh Covid CASES would skyrocket along with testing increases.

Win/Win for the control hungry LEFT.
From a guy who still thinks covid isnt a big deal.
 

aloyouis

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From a guy who still thinks covid isnt a big deal.
Your schtick has been tired on ALL of PP from long before your first Assclowning.

Is there a single thread that you don't "Midgar" all over?

Is there a single useful thread you have "given" to the planet?

100% snark and made up stuff is all you contribute unless there is a "contribution" we don't know about.
 

Beaglebay

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Nothing political here, just researchers sharing medical facts.
 

Inspector_50

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Nothing political here, just researchers sharing medical facts.
Too late they already made covid political and even though I screamed about why it shouldnt be after my wife almost died from it, it didnt alter it from being thought of that way.
 

aloyouis

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Nothing political here, just researchers sharing medical facts.
Interesting. I wonder if there are newer versions of that article? I can't look right now. I am about to speak on a call....
 

patswin

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Nothing political here, just researchers sharing medical facts.

Your Coronavirus Test Is Positive. Maybe It Shouldn’t Be.​


Some of the nation’s leading public health experts are raising a new concern in the endless debate over coronavirus testing in the United States: The standard tests are diagnosing huge numbers of people who may be carrying relatively insignificant amounts of the virus.
Most of these people are not likely to be contagious, and identifying them may contribute to bottlenecks that prevent those who are contagious from being found in time. But researchers say the solution is not to test less, or to skip testing people without symptoms, as recently suggested by the Centers for Disease Control and Prevention.
Instead, new data underscore the need for more widespread use of rapid tests, even if they are less sensitive.
“The decision not to test asymptomatic people is just really backward,” said Dr. Michael Mina, an epidemiologist at the Harvard T.H. Chan School of Public Health, referring to the C.D.C. recommendation.



“In fact, we should be ramping up testing of all different people,” he said, “but we have to do it through whole different mechanisms.”


In what may be a step in this direction, the Trump administration announced on Thursday that it would purchase 150 million rapid tests.
The most widely used diagnostic test for the new coronavirus, called a PCR test, provides a simple yes-no answer to the question of whether a patient is infected.
But similar PCR tests for other viruses do offer some sense of how contagious an infected patient may be: The results may include a rough estimate of the amount of virus in the patient’s body.
“We’ve been using one type of data for everything, and that is just plus or minus — that’s all,” Dr. Mina said. “We’re using that for clinical diagnostics, for public health, for policy decision-making.”



But yes-no isn’t good enough, he added. It’s the amount of virus that should dictate the infected patient’s next steps. “It’s really irresponsible, I think, to forgo the recognition that this is a quantitative issue,” Dr. Mina said.
The PCR test amplifies genetic matter from the virus in cycles; the fewer cycles required, the greater the amount of virus, or viral load, in the sample. The greater the viral load, the more likely the patient is to be contagious.
This number of amplification cycles needed to find the virus, called the cycle threshold, is never included in the results sent to doctors and coronavirus patients, although it could tell them how infectious the patients are.
In three sets of testing data that include cycle thresholds, compiled by officials in Massachusetts, New York and Nevada, up to 90 percent of people testing positive carried barely any virus, a review by The Times found.


On Thursday, the United States recorded 45,604 new coronavirus cases, according to a database maintained by The Times. If the rates of contagiousness in Massachusetts and New York were to apply nationwide, then perhaps only 4,500 of those people may actually need to isolate and submit to contact tracing.
One solution would be to adjust the cycle threshold used now to decide that a patient is infected. Most tests set the limit at 40, a few at 37. This means that you are positive for the coronavirus if the test process required up to 40 cycles, or 37, to detect the virus.
Tests with thresholds so high may detect not just live virus but also genetic fragments, leftovers from infection that pose no particular risk — akin to finding a hair in a room long after a person has left, Dr. Mina said.



Any test with a cycle threshold above 35 is too sensitive, agreed Juliet Morrison, a virologist at the University of California, Riverside. “I’m shocked that people would think that 40 could represent a positive,” she said.
T
Is this helpful?

A more reasonable cutoff would be 30 to 35, she added. Dr. Mina said he would set the figure at 30, or even less. Those changes would mean the amount of genetic material in a patient’s sample would have to be 100-fold to 1,000-fold that of the current standard for the test to return a positive result — at least, one worth acting on.

It’s just kind of mind-blowing to me that people are not recording the C.T. values from all these tests, that they’re just returning a positive or a negative,” one virologist said.
The Food and Drug Administration said in an emailed statement that it does not specify the cycle threshold ranges used to determine who is positive, and that “commercial manufacturers and laboratories set their own.”
The Centers for Disease Control and Prevention said it is examining the use of cycle threshold measures “for policy decisions.” The agency said it would need to collaborate with the F.D.A. and with device manufacturers to ensure the measures “can be used properly and with assurance that we know what they mean.”
The C.D.C.’s own calculations suggest that it is extremely difficult to detect any live virus in a sample above a threshold of 33 cycles. Officials at some state labs said the C.D.C. had not asked them to note threshold values or to share them with contact-tracing organizations.
For example, North Carolina’s state lab uses the Thermo Fisher coronavirus test, which automatically classifies results based on a cutoff of 37 cycles. A spokeswoman for the lab said testers did not have access to the precise numbers.



This amounts to an enormous missed opportunity to learn more about the disease, some experts said.
“It’s just kind of mind-blowing to me that people are not recording the C.T. values from all these tests — that they’re just returning a positive or a negative,” said Angela Rasmussen, a virologist at Columbia University in New York.
“It would be useful information to know if somebody’s positive, whether they have a high viral load or a low viral load,” she added.



Officials at the Wadsworth Center, New York’s state lab, have access to C.T. values from tests they have processed, and analyzed their numbers at The Times’s request. In July, the lab identified 872 positive tests, based on a threshold of 40 cycles.
With a cutoff of 35, about 43 percent of those tests would no longer qualify as positive. About 63 percent would no longer be judged positive if the cycles were limited to 30.
In Massachusetts, from 85 to 90 percent of people who tested positive in July with a cycle threshold of 40 would have been deemed negative if the threshold were 30 cycles, Dr. Mina said. “I would say that none of those people should be contact-traced, not one,” he said.
Other experts informed of these numbers were stunned.
“I’m really shocked that it could be that high — the proportion of people with high C.T. value results,” said Dr. Ashish Jha, director of the Harvard Global Health Institute. “Boy, does it really change the way we need to be thinking about testing.”
Dr. Jha said he had thought of the PCR test as a problem because it cannot scale to the volume, frequency or speed of tests needed. “But what I am realizing is that a really substantial part of the problem is that we’re not even testing the people who we need to be testing,” he said.
 

Inspector_50

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That's what effective research does; it evolves as it uncovers new data.
OMG this. Believe it or not, we don't know everything about a virus right out of the box, which is why we have research and studies and trials. People get upset because this changes so they think its a fraud.
 

aloyouis

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OMG this. Believe it or not, we don't know everything about a virus right out of the box, which is why we have research and studies and trials. People get upset because this changes so they think its a fraud.
We retaking about testing inaccuracy here Midrange. Stay on topic.;)
 

patswin

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That's what effective research does; it evolves as it uncovers new data.

That's what effective research does; it evolves as it uncovers new data.
Sorry for the duplicate quote.... can't figure out how to delete one. What kills me is the point that if they lowered the threshold to 30, 85-90 percent of the positives in this state go away. And if was 35, a whole lot of them go away. One must ask themselves what kind of restrictions we'd have with that many fewer positives. It's clear that the number of test cycles needed is debatable, and that this state, by insisting on so many cycles, is doing all they can to maximize the crisis. Meanwhile, the collateral damage from the restrictions continues to rampage.
 

Inspector_50

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Sorry for the duplicate quote.... can't figure out how to delete one. What kills me is the point that if they lowered the threshold to 30, 85-90 percent of the positives in this state go away. And if was 35, a whole lot of them go away. One must ask themselves what kind of restrictions we'd have with that many fewer positives. It's clear that the number of test cycles needed is debatable, and that this state, by insisting on so many cycles, is doing all they can to maximize the crisis. Meanwhile, the collateral damage from the restrictions continues to rampage.
I work for a pretty average size school district. So far just since the end of the year, we have schools that have 27 teachers out with covid...we have an HR director in the hospital, we have IT in the hospital, and the end of last year we had two die in admin. 270k people have died since March....so, yeah restrictions, they need to be there until this vaccine gets out to enough people where those numbers start to go down.
 

foobahl

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Sorry for the duplicate quote.... can't figure out how to delete one. What kills me is the point that if they lowered the threshold to 30, 85-90 percent of the positives in this state go away. And if was 35, a whole lot of them go away. One must ask themselves what kind of restrictions we'd have with that many fewer positives. It's clear that the number of test cycles needed is debatable, and that this state, by insisting on so many cycles, is doing all they can to maximize the crisis. Meanwhile, the collateral damage from the restrictions continues to rampage.
That is a double edged sword. Less positives means a more deadly virus.
 

patswin

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That's what effective research does; it evolves as it uncovers new
That is a double edged sword. Less positives means a more deadly virus.
I disagree. If you read it carefully these experts are saying exactly the opposite. They are saying that people with a low viral load, which might constitute nothing more than a fragment of DNA, should not be deemed positive. They are saying "Most of these people are not likely to be contagious, and identifying them may contribute to bottlenecks that prevent those who are contagious from being found in time"
They also state more, not less testing is needed. But that the rapid tests more quickly identify those who are contagious, and that this, in turn, leads to more effective quarantine, since you are focused on those who really are a threat to spread it. So basically, less PCR testing, or less stringent, and more rapid tests.

if you more effectively identify and isolate the truly sick, less people die, not more. I'll give you an example. On Sunday, I went to Woburn to hit Lowe's for some supplies. On my way, I pass a Lahey Health testing clinic. The line of cars was queued through the parking lot in many rows, and then out of the parking lot and down the street for 1.5 miles. On a Sunday. At 9 AM. Let's just assume that not every one in that line is positive. Or even half. It takes 24 hours at least just to process those tests. That time could be spent doing rapid tests, the line moves faster, and the truly sick are more quickly found, and this in turn limits how many people they might infect. Seems reasonable to me.
 

foobahl

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I disagree. If you read it carefully these experts are saying exactly the opposite. They are saying that people with a low viral load, which might constitute nothing more than a fragment of DNA, should not be deemed positive. They are saying "Most of these people are not likely to be contagious, and identifying them may contribute to bottlenecks that prevent those who are contagious from being found in time"
They also state more, not less testing is needed. But that the rapid tests more quickly identify those who are contagious, and that this, in turn, leads to more effective quarantine, since you are focused on those who really are a threat to spread it. So basically, less PCR testing, or less stringent, and more rapid tests.

if you more effectively identify and isolate the truly sick, less people die, not more. I'll give you an example. On Sunday, I went to Woburn to hit Lowe's for some supplies. On my way, I pass a Lahey Health testing clinic. The line of cars was queued through the parking lot in many rows, and then out of the parking lot and down the street for 1.5 miles. On a Sunday. At 9 AM. Let's just assume that not every one in that line is positive. Or even half. It takes 24 hours at least just to process those tests. That time could be spent doing rapid tests, the line moves faster, and the truly sick are more quickly found, and this in turn limits how many people they might infect. Seems reasonable to me.
If the people with the low viral load are deemed negative, and that would be a large portion of the positives, wouldn't that also mean that the percentage of deaths to positives rises exponentialy also? How can it not? If there are for all practical purposes less positive cases (which in my reading is what you are stating), the deaths do not change, making it more deadly.
 

patswin

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If the people with the low viral load are deemed negative, and that would be a large portion of the positives, wouldn't that also mean that the percentage of deaths to positives rises exponentialy also? How can it not? If there are for all practical purposes less positive cases (which in my reading is what you are stating), the deaths do not change, making it more deadly.
Well, I'd agree with you that deaths as a percentage of the tests might rise. And obviously my points are hypothetical based on what the NYT piece says. But if you are catching contagious people more efficiently and quickly, you're getting them under control so to speak a lot faster because number one you aren't waiting 24-48 hours for the result, and with the rapid test, you have the results really fast, and you're testing a huge amount more people in a day than you are with the PCR test. So the reduction in deaths comes from catching the contagious faster. I suppose another angle would be measuring deaths as a percentage of those tested, as opposed to those tested positive. I hope that sorta kinda makes sense, if the words convey what's in my head, which admittedly can be a challenge sometimes.
 

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Well, I'd agree with you that deaths as a percentage of the tests might rise. And obviously my points are hypothetical based on what the NYT piece says. But if you are catching contagious people more efficiently and quickly, you're getting them under control so to speak a lot faster because number one you aren't waiting 24-48 hours for the result, and with the rapid test, you have the results really fast, and you're testing a huge amount more people in a day than you are with the PCR test. So the reduction in deaths comes from catching the contagious faster. I suppose another angle would be measuring deaths as a percentage of those tested, as opposed to those tested positive. I hope that sorta kinda makes sense, if the words convey what's in my head, which admittedly can be a challenge sometimes.
Stats are tricky things. Ask any politician after a couple of drinks.
 

patswin

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Stats are tricky things. Ask any politician after a couple of drinks.
Could not agree more. I was just thinking it over some more... ultimately deaths are the lowest common denominator and if you reduce it that's the goal, and the other stats are not as big a deal. It is just clear that the present approach is not effective, and as Baron's earlier post said, doubling down on the wrong actions is having no effect on the spread, and I am not sure how anyone can disagree with that. Thanks for the thoughtful critique on my post as well.
 
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