How long does mono last?

Awhile: The virus has incubation period of approximately four to six weeks.Signs and symptoms such as fever and sore throat usually lessen within a couple of weeks, although fatigue, enlarged lymph nodes and a swollen spleen may last for a few weeks longer.Mononucleosis may cause enlargement of the spleen. In extreme cases, your spleen may rupture. Sudden pain in left upper abdomen contact doctor.

2-3 wks: For most teens or adults this would gradually improve by 2-3 weeks which is the general contageous period. A subset of 1/4 may have persisting problems (tired,lethargic) for 2-3 mo. There is a myth about a "chronic" mono (yrs) that has been refuted by the CDC.