This virus is transmitted in infected saliva through coughing, sneezing, and kissing. Contrary to popular belief, mono is not very contagious. Even people in the same household rarely come down with it. Most teens have only mild symptoms for a week. Even those with severe symptoms usually feel completely well in 2 to 4 weeks.
Complications are rare and require hospitalization when they occur.
The most common complication is dehydration from not drinking enough fluids. Breathing may be obstructed by enlarged tonsils, adenoids, and other lymph tissue in the back of the throat. On rare occasions, the enlarged spleen will rupture if the abdomen is hit or strained. The symptoms are present for at least 6 months. There is no good scientific evidence to support mononucleosis as the cause of chronic fatigue syndrome.