A friend tells me that by the time you feel the first symptoms of a cold (runny nose, sore throat, whatever the first symptoms are), your immune system has actually already killed the virus, and the whole sequence of symptoms, from sore throat, to runny nose, to sneezing, to coughing, are just the body going through a kind of unnecessary routine, triggered by the virus, but not actually killing it since it's already been killed.
This sounds unlikely to me, but is it true?
(I do understand that it's not clear what it means for a virus to killed since it's not clear a virus is alive in the first place. I don't know if the claim is that the virus has been deactivated, or actually removed from the body, or what. But the gist is that the virus has basically been "dealt with" before you feel the symptoms.)
(Also, I realize that even if the threat of the virus has already been removed, perhaps the sequence of symptoms is somehow a necessary part of the way the immune system works -- related, say, to how the body remembers the virus for the next time -- but still the question is whether the symptoms are not about actually ridding the body of the virus right now, since it's already been dealt with.)