On another board I read, someone claimed they were sick for several weeks because they kept getting reinfected with the same cold, so after disinfecting their stuff, they recovered. However, I thought that once you recovered from a virus, you were immune to it. You can get another mutated strain, but wouldn’t the cold virus you just had not affect you anymore?
My understanding is that you normally end up with immunity after you have recovered from an infection with a strain, at least for the common viruses that cause colds. The immunity is keyed to the strain you got so it may not be terribly effective against another cold-causing virus.
Now, if you have a depressed immune system (e.g. from AIDS), I could see how you could have a problem with repeated infections.
So that cold you just had can’t lurk on, say, your computer keyboard or your countertops and reinfect you after you’ve already had it?
No, the common cold will not reinfect the person who spread the germs. But if you’re really leaving your cold germs everywhere, well, that makes you a terrible neighbor.
Well, this person said they were leaving their cold germs around their house and then reinfecting themselves, not involving their neighbors.
You do generally acquire immunity once you have a cold virus, but there are something like 100 different strains floating around. This person could have had a very long cold, or could have caught a different strain after just getting over one. Happened to me a couple of months ago. I had one day of feeling healthy between bouts of virus.
Think of it this way. If you have a cold, you have virus in your system. Your immune system goes to work on defeating it. If you are exposed to the same virus again (say you sneeze on your keyboard), you are getting exposed to a virus that’s already in your body anyway. So how can you get sick all over again?
Not the cold, but I was told by a parasitology teacher that you can reinfect yourself with worms and other things that take the fecal-oral route.
You can’t develop an immunity to parasites.
It’s also possible the person had a sinus infection, not a cold, and that’s why it lingered so long.