> A PCR test that is sensitive is a great tool. Remember the NBA bubble? A less sensitive test would have allowed outbreaks inside the bubble, making some player sick and unable to play, as well as eroding the public's confidence on PCR tests.
A hammer is a great tool. It is not a great tool for repairing broken pottery.
PCR is the ideal tool if you want to detect infinitesimal amounts of a specific nucleic acid sequence. It is not a great tool if you want to use it to define "illness" or "infectivity", for it cannot tell you anything about those questions.
Can you use PCR to cast the widest possible net, and isolate literally everyone who has any shred of viral RNA? Yes. That's essentially what we've been doing. It is a strategy, and this strategy is appropriate in some situations. This strategy becomes a problem when you forget that you're allowing a lot of false positives to be caught up in the process, and start behaving as if "a positive" is a meaningful clinical diagnosis. Now that we have highly effective vaccines and are out of the acute phase of the crisis, it's time to adjust our definition of "infection" to more accurately reflect the true clinical meaning of the word.