And sure you will eventually get infected by one more cold, because there remain more than 300 different cold infections. However you will certainly unlikely acquire the same runny nose virus that you had in the past since you have developed immunity to that virus.

Adults have already had a lot of the runny nose infections. Grownups have established resistance to the ones they have suffered from. Therefore there are not so numerous of runny nose infections remaining for parents to acquire. That is why grownups only succumb to a couple of runny noses per year and children usually get 10-12 colds per year.
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