5 ms·
I don't get this - if you're symptomatic beyond day 9, how can you not be contagious? A dry cough, for example, should be caused by the virus still being alive
by nikolay 6y ago
I don't get this - if you're symptomatic beyond day 9, how can you not be contagious? A dry cough, for example, should be caused by the virus still being alive in the upper respiratory tract, i.e. you still should be able to infect others. Did they test aerosols, too?
- peteretep 6y ago> A dry cough, for example, should be caused by the virus still being alive in the upper respiratory tract Why? I thought the body’s (potentially delayed) reaction caused the cough, not the virus
- nikolay 6y agoWe have the instinct to cough to clear our air passages even without pathogens in certain cases. The virus is triggering these thru some irritation in order to spread to other people.
- strstr 6y agoNaive guess: the damage was already done. Cough is a response to the damage caused by the virus, not to the virus itself. If you get shot, you still have a bullet wound when the bullet comes out.
- nikolay 6y agoDamaged cells are cleaned up pretty fast. Of course, it's the virus causing damage, but we cough for the purpose to clear up the passages. In addition, the respiratory viruses probably trigger the cough as a vehicle to spread to other people.
- xorcist 6y agoWhat you feel as symptoms are your immune responses, you can not "feel" the actual virus. The immune reponse should go on for longer than the virus is functional. Also, there has to be above a certain viral load to be contagious. I am however far from qualified to even guess what the thresholds are and I would think that it is mostly a matter of definition.
- nikolay 6y agoCoughing is a taxing activity - it wastes energy, and causes discomfort. We cough for a reason - I doubt it's from the solidarity to infect others. Of course we can sense the virus, but the irritation it causes. Do all viruses, which replicate in the nasopharyngeal tract, trigger coughs? Maybe some viruses evolve to cause irritation similar to air passage obstruction, which triggers the instrict to clear your throat up?
- kadoban 6y agoOur bodies are not perfect or omniscient. We cough because it is evolutionarilly favored as a way to dislodge irritants, and viruses are evolutionarily favored to cause that coughing response strongly in order to spread. Coughing too long seems like a very possible consequence of those.
- noselasd 6y agoThe irritation still persists from the damaged tissue after the virus is eliminated. It takes time to rebuild.
- nikolay 6y agoSo, senescent cells are just left for days to build up damage? We have mechanisms to clear up dead cells, many of them which actually killed themselves via apoptosis and were not directly killed by the virus.
- roenxi 6y agoLive virus doesn't really cause symptoms as such, although they evolve to take advantage of it. The virus is basically re-purposing then melting a bunch of cells. The body's immune response is killing the viral structures and turning whole areas into the cellular equivalent of a battleground, killing off anything that is or is likely to be controlled by the virus. Many of the worst symptoms aren't related to the presence or absence of the virus itself. If someone is turning blue from lack of oxygen, it isn't that the virus is doing anything here and now. It is that their lungs are non-functional from damage that the virus already did (note: past tense). You could remove every trace of active coronavirus from them and while they'd probably not get worse they also wouldn't get better very quickly. New lungs don't grow overnight.
- christkv 6y agoPCR tests for RNA fragments. After 9 days it's likely you are surveying the battle field remains not actual live virus.