Really feels like we lack a framework for defining an infection. If I put one viral cell (not sure if correct term) in you, and your body can handle it no probl

Really feels like we lack a framework for defining an infection. If I put one viral cell (not sure if correct term) in you, and your body can handle it no problem, are you infected? I've never "had covid". But I've probably had some amount of covid in my system. I'm sure there are some tests that may have said I have had covid. Is there a degree of infection that confers a specialized immune response? A level of viral load that can exist passively from presence in the environment but suppressed to low level by your immune system?