text: can i get mono ( mononucleosis)? from someone who has had before, roughly 4-6 years ago? since mono stays with your for life... is it possible it could still be passed on. registered nurse here; first let me clear up the myth, (untruth about mononucleosis), it does not stay with you for life.  the incubation period is about 7 to 21 days, give or take 3 or 4 days in either direction.  someone that had mono 6 years ago, is in no way, shape, form or fashion caring it today, unless they have been re-exposed to the viral infection.