Maybe have you heretofore suffered through a cold virus? Likely did you recover from the cold? Obviously you recovered! You cannot heal a runny nose directly, but your immune system generally establishes immunity to any cold virus within a few days. That is called cured by your own immune system!

Parents have in the past had a lot of the runny nose viruses. Grownups have created resistance to the colds they have had. Therefore there are not quite as many runny nose infections existing for grownups to catch. That is why grownups only succumb to a few colds each year and youngsters acquire 10-12 runny noses each year.
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