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Confirmed PCR cases (can someone from France confirm or disprove this? Is the government only using swabs + PCR?) are a problem, because they keep on piling but

Confirmed PCR cases (can someone from France confirm or disprove this? Is the government only using swabs + PCR?) are a problem, because they keep on piling but you lose track of who's infectious. You have very large, almost inflated case numbers, but (in the absence of symptoms) you don't know if those people are still spreading the virus or had it and are recovering. That's because, if you are positive at a PCR test and without any symptom you may: - Have not yet developed symptoms, and are infectious - Have no symptoms, and are infectious - Have cleared the virus, and are no longer infectious Viral RNA can last in the throat for weeks in some cases (and it's not unique to this virus). That is why you can't detect the virus just with this test in absence of anything else (and the British Medical Journal wrote about this recently: advice to the doctors on how to interpret tests). The New England Journal of Medicine argued for far more frequent antigen testing as a way to keep track of cases that are important to isolate, that is, the ones that are infectious[1]. My country did the same mistake (also using serological tests to assess positivity and infectiousness, a stupid mistake that just increased the backlog of tests) and of course tracing blew up. EDIT: You can voice your disagreement instead of downvoting. [1] https://www.nejm.org/doi/full/10.1056/NEJMp2025631 https://www.nejm.org/doi/full/10.1056/NEJMp2025631

skinnymuch 6y ago
Am I misreading or does not having symptoms make you not infectious? I can’t tell if you’re saying that or not. Why do the test numbers keep on piling up?
- lbeltrame 6y ago
  No, that's not what I meant. I meant that a positive PCR test without any symptoms can't tell you if: - you're about to have the disease (presymptomatic) - you have the disease (asymptomatic) - you already cleared the virus You might be infectious, but you don't know. And given the time window of infectiousness, delays in testing can give you a "positive, please isolate" notice when it's too late, and you potentially have spread the virus to others without knowing. OTOH, antigen tests detect virus proteins (with far lower sensitivity), so it's far more likely that you have an active infection if you are positive.

skinnymuch 6y ago

Am I misreading or does not having symptoms make you not infectious? I can’t tell if you’re saying that or not. Why do the test numbers keep on piling up?

lbeltrame 6y ago
No, that's not what I meant. I meant that a positive PCR test without any symptoms can't tell you if: - you're about to have the disease (presymptomatic) - you have the disease (asymptomatic) - you already cleared the virus You might be infectious, but you don't know. And given the time window of infectiousness, delays in testing can give you a "positive, please isolate" notice when it's too late, and you potentially have spread the virus to others without knowing. OTOH, antigen tests detect virus proteins (with far lower sensitivity), so it's far more likely that you have an active infection if you are positive.