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.
Varies. Mononucleosis is a viral illness. It can last from a few days to several weeks to months. Rest, nutrition, and time are necessary for treatment. One can have a mild case or a more severe case to include a hepatitis. If not progressing, please follow up with your pcp or an infectious disease doctor.
See below. Most cases of mono resolve over a 2-3 week period. The sore throat lasts 3-5 days then resolves over the next 7 days. Fever usually lasts 10-14 days but is low grade for the last 5-7 days. The fatigue and prostration resolves more gradually sometimes with periods of improvement alternating with recrudescence.
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. Read more...