I don't know the answer to your question, but it would make sense unless the antibody test(s) look for a specific type of antibody to COVID-19 that is produced naturally when infected and not just any antibodies that might be produced when vaccinated.
incorrect, PCR tests detect any virus matter - active or otherwise. This is a very important distinction since we've seem to lost our minds collectively and label PCR tests with a cycle threshold of >40 as a true positive.
"lost our minds collectively" -- no, made a sane tradeoff in the sensitivity vs. specificity ratio when the disease is common. It's not like the sensitivity is wonderful even with a large number of PCR cycles, and the false positive rate was not too bad.
As the disease becomes less common, it makes sense to turn down the sensitivity of the test. Base rate fallacy, yada yada.
here's a study showing above CT 32 not a single live virus was able to be cultured [1] - if this study accurately portrays reality then there's nothing resembling sanity with PCR CTs >40
People who are infected will not necessarily have a single live virus in a swab you collect. Yes, if you can't culture it, they probably are not infectious right now but that is a different distinction.
You're also putting a whole lot of weight on a study with what, about 50 total positives? And of them, very few with a Ct of over 35.
Even your studies show a relatively low false positive rate with high numbers of cycles, and it's hoped that it increases sensitivity. No, we have no perfect data, because we have no perfect "infection test".
High sensitivity was very worthwhile early in the pandemic, when infection was common and the predictive value of a test with a somewhat higher false positive rate was still high. Now that COVID is becoming rarer, we should absolutely be reducing cycle counts. The target should be to keep >75% of positives with actual infection even as the underlying rate of the disease decreases. I think we've exceeded this threshold by a large margin thus far. If you have a cogent statistical argument that disagrees instead of handwaving about cycle counts, I'm willing to listen.
1st study says zero active virus beyond CT>32 and 2nd study shows 34ct is the cutoff for infectivity and that 2nd study also cites a 3rd study that ct>35 decreased to 8% active viruses
All of those numbers are below 40ct - if this doesn't convince you that 40ct is the wrong number I don't know what to say - you've provided zero evidence that 40ct is beneficial and try to downplay extremely high false positives shown in three studies when you go to 40ct
"Extremely high false positives"-- no, inability to culture from the specimens, which isn't the same thing as a false positive. Please stop conflating the two.
It's a sensitivity vs. specificity issue, as I've said before, and I'm willing to listen to arguments on those grounds.
As the studies you've cited show, the vast majority of positive samples become so before 30 cycles. Then there's these relatively few "weak positive" results, where the ability to culture live virus is less. There's not enough of these to explain the number of cases, deaths, or overall excess mortality (as you've attempted to say elsewhere here, and others have rightfully corrected you). And these results being considered a positive is arguably a good thing while the virus is very common, as I've attempted to explain to you.
> 2nd study shows 34ct is the cutoff for infectivity and that 2nd study also cites a 3rd study that ct>35 decreased to 8% active viruses
Yes, but "infective at the moment you took the test" is not a useful metric. You want more people to be positive than this, so you can A) contact trace people who were infectious immediately before, and B) get people who were just infected to stay home -before- they're infectious.
Of course, now that we're on a major downslope of cases, this tradeoff is changing...
This is just silly, if you reject the methodology used in these studies to determine effective CT thresholds then it's pretty pointless having a conversation with someone who refuses to do anything other than restate their opinion without providing and evidence that supports their opinions.
See: https://www.fda.gov/consumers/consumer-updates/coronavirus-d...
I don't know the answer to your question, but it would make sense unless the antibody test(s) look for a specific type of antibody to COVID-19 that is produced naturally when infected and not just any antibodies that might be produced when vaccinated.