4 ms·

Because science is complex, there is no universal answer to "what is the right CT" for PCT. Each assay/test configuration and mechanism has its own characteris

Because science is complex, there is no universal answer to "what is the right CT" for PCT. Each assay/test configuration and mechanism has its own characteristics and constraints. The right number can vary, even from lab to lab using "the same test", due to variance in sample technique, storage, source of materials, etc. And besides, the average CT for positive tests has been below 30 for the vast majority of tests, with something like a 0.005% false positive rate [1]. The people who are barking about CT are misinformation specialists, not infectious disease specialists [1] https://twitter.com/LaymansScience/status/1345381121706651649 https://twitter.com/LaymansScience/status/134538112170665164... So to the anti-vaxers who want to score points over CT values, just ask them what CT threshold they use in their own lab, and how they justify it vs 1 higher, or 2 lower, or double, or half. They don't have answers because it is complex and they don't know what the specific lab(s) are doing.

beagle3 6y ago
With all due respect, this is how religion is done, not how science is done. I am not an antivaxer, I am up to date on all my vaccines. I was reading the Pfizer report, and I noticed that, w.r.t to severe disease, the placebo arm had 4 people, and the vaccine arm had 1 (please don’t trust me and check for yourself). That is 75% RRR with (any reasonable) confidence interval (0,100). I have mentioned it and got attacked for being an anti vaxxer, mostly by people who had not read the Pfizer report, would not understand it if they did, but were adamant that “it is 95%. Pfizer said so, and the FDA approved”. Statistics people I reached out too, however confirmed my reading of the results. Now, you may very well be right, but your response is indistinguishable from that (provably wrong) attack I received, except perhaps to PCR experts. Similarly, almost everyone I’ve met, including many biologists and doctors, claim that two weeks after the 1st vaccine does protection is 50% and only gets to 95% after the 2nd one, which is very wrong (but only people who looked at Pfizer’s data are aware of that). Do you actually know what you said for sure, or just repeating what you’ve been told? Furthermore, I am at this second stuck in Israel, a country with 35% vaccinated population, 6 weeks of lockdown (of which 3 have been relatively tight). I had believed the infectious disease experts in the beginning, but every single falsifiable prediction they made since March 2020 has been falsified. And in the times I looked at their data and methodology, it was abysmal 3rd grade statistics and politically motivated. So, my trust for “leave it to the experts” right now is at absolute zero. (And... the only data I was able to find here in Israel is unofficial, but supposedly they use 35 cycles - which every PCR using biologist I’ve talked to told me was bonkers, although some said “well, perhaps they have a good reason to”. This is not science. It’s religion)
- jhayward 6y ago
  https://www.medrxiv.org/content/10.1101/2020.10.25.20219048v1 https://www.medrxiv.org/content/10.1101/2020.10.25.20219048v... Page 25. Actual infectious disease scientists. There are two conclusions you can draw from these graphs: 1) The vast majority of 'positive' PCR tests do not need > 30 cycles to demonstrate presence of virus. 2) Actual, employed, doing-the-work scientists do indeed use > 30 cycles, and publish the work, to demonstrate facts with actual scientific merit. Of course, your buddies who tell you that "it's bonkers" are a reliable source, right?
  - beagle3 6y ago
    My buddies do PCRs every day, some of them for decades. Non of them work on human tissues, but they all have done PhDs and postdocs in prestigious labs, and some of them are already tenured and considered rising stars. So, yes, they are a reliable source. Thank you for the medrxiv pointer, I will read it later today when I have the time. The conclusions mins you, which one should never trust without actually reading the paper (and I admit I have not, especially not pg 25 you pointed to) are: “ Conclusions Community SARS-CoV-2 infections show marked variation in viral load. Ct values could be a useful epidemiological early-warning indicator.” At face value, this reads “Ct value should be published”. But I will only adopt this interpretation (or disown it) after reading the entire paper.
  - beagle3 6y ago
    Yes, if you only look at pg 25, you’d get these results. But if you actually read the paper (which actually supports the conclusions they reaxh). Median Ct>34.9 group seems to be essentially false positives, and even Ct>33 is not strong, whereas median Ct=~24 is a very strong positive. Turns out, my buddies seem to be right and you sit, by your own reference, are wrong in claiming that there’s no reason to publish Ct. You think you are part of the scientific solution, but you have just proved yourself to be part of the cargo cult religion.

beagle3 6y ago

With all due respect, this is how religion is done, not how science is done. I am not an antivaxer, I am up to date on all my vaccines. I was reading the Pfizer report, and I noticed that, w.r.t to severe disease, the placebo arm had 4 people, and the vaccine arm had 1 (please don’t trust me and check for yourself). That is 75% RRR with (any reasonable) confidence interval (0,100). I have mentioned it and got attacked for being an anti vaxxer, mostly by people who had not read the Pfizer report, would not understand it if they did, but were adamant that “it is 95%. Pfizer said so, and the FDA approved”. Statistics people I reached out too, however confirmed my reading of the results. Now, you may very well be right, but your response is indistinguishable from that (provably wrong) attack I received, except perhaps to PCR experts. Similarly, almost everyone I’ve met, including many biologists and doctors, claim that two weeks after the 1st vaccine does protection is 50% and only gets to 95% after the 2nd one, which is very wrong (but only people who looked at Pfizer’s data are aware of that). Do you actually know what you said for sure, or just repeating what you’ve been told? Furthermore, I am at this second stuck in Israel, a country with 35% vaccinated population, 6 weeks of lockdown (of which 3 have been relatively tight). I had believed the infectious disease experts in the beginning, but every single falsifiable prediction they made since March 2020 has been falsified. And in the times I looked at their data and methodology, it was abysmal 3rd grade statistics and politically motivated. So, my trust for “leave it to the experts” right now is at absolute zero. (And... the only data I was able to find here in Israel is unofficial, but supposedly they use 35 cycles - which every PCR using biologist I’ve talked to told me was bonkers, although some said “well, perhaps they have a good reason to”. This is not science. It’s religion)

jhayward 6y ago
https://www.medrxiv.org/content/10.1101/2020.10.25.20219048v1 https://www.medrxiv.org/content/10.1101/2020.10.25.20219048v... Page 25. Actual infectious disease scientists. There are two conclusions you can draw from these graphs: 1) The vast majority of 'positive' PCR tests do not need > 30 cycles to demonstrate presence of virus. 2) Actual, employed, doing-the-work scientists do indeed use > 30 cycles, and publish the work, to demonstrate facts with actual scientific merit. Of course, your buddies who tell you that "it's bonkers" are a reliable source, right?
- beagle3 6y ago
  My buddies do PCRs every day, some of them for decades. Non of them work on human tissues, but they all have done PhDs and postdocs in prestigious labs, and some of them are already tenured and considered rising stars. So, yes, they are a reliable source. Thank you for the medrxiv pointer, I will read it later today when I have the time. The conclusions mins you, which one should never trust without actually reading the paper (and I admit I have not, especially not pg 25 you pointed to) are: “ Conclusions Community SARS-CoV-2 infections show marked variation in viral load. Ct values could be a useful epidemiological early-warning indicator.” At face value, this reads “Ct value should be published”. But I will only adopt this interpretation (or disown it) after reading the entire paper.
- beagle3 6y ago
  Yes, if you only look at pg 25, you’d get these results. But if you actually read the paper (which actually supports the conclusions they reaxh). Median Ct>34.9 group seems to be essentially false positives, and even Ct>33 is not strong, whereas median Ct=~24 is a very strong positive. Turns out, my buddies seem to be right and you sit, by your own reference, are wrong in claiming that there’s no reason to publish Ct. You think you are part of the scientific solution, but you have just proved yourself to be part of the cargo cult religion.