Why don't more adults get mono?

Got EBV as a child?: In many parts of the world, children catch ebv virus when they are still young. At that age, they get mild flu-like symptoms for a few days, and then are well again (they usually do not get a "mono" illness). Because their bodies already carry ebv virus, when they become teens or adults and kiss other people with ebv virus, they do not catch another ebv disease from the other people.

See below: The vast majority of people have been infected by ebv and have had mono by the time they are a young adult. Sometimes the symptoms of mono can mimic the flu. Many people have had flu-like symptoms that in reality may be a mild case of mono caused by ebv. Once you have had mono, you should not be able to get it again.

Childhood infection: Most cases of infectious mononucleosis ("mono") occur during childhood. The great majority of people make protective antibody that last long term, decreasing the incidence (new cases) of mono in adulthood.