"one would have to determine the percentage of viable virus particles. Hard to tell whether that's even feasible at scale ... It's not too bad though. At worst this causes a higher than expected false-positive rate."
I'm not sure you're aware of the scale of the problem. There have been studies that correlated PCR test results with ability to do viral culturing and concluded about 60% of all positive test results did not imply infectiousness. For example, this one:
My point was that the viral culturing might not be feasible for large-scale testing. In that case, we might have to stick to PCR.
The correct response to the PCR not detecting what people actually need to know is to shut down mass testing entirely. There is no point in mass testing if it creates chaos and doesn't help, which is what's happening (there is no correlation between testing levels and incidence levels, killing the theory that test test test = better results).
> Also, COVID tests don't actually detect COVID or even SARS-CoV-2, they detect RNA debris from destroyed SARS-CoV-2. Thus it's expected that if someone's body fights off the virus immediately if they're exposed to it, they will still test positive.
Slightly untrue. The particles gathered from infected and spreading persons are fully functional, by definition. To distinguish these cares from immune people, one would have to determine the percentage of viable virus particles. Hard to tell whether that's even feasible at scale. It's not too bad though. At worst this causes a higher than expected false-positive rate.