how long does glandular fever last

Glandular fever (infectious mononucleosis) usually makes people feel acutely unwell for about 2–3 weeks, but the tiredness can linger for weeks or even months in some cases. Most people do eventually recover fully.

Typical illness timeline

• The main infection phase (fever, sore throat, swollen glands) usually lasts about 2–3 weeks.

• Many people feel much better by 4 weeks, though not yet “back to normal”.

• A small group have fatigue and low stamina that can last several months, but most of them gradually improve over time.

How long symptoms can last

• Sore throat and fever: often worst in the first week, then ease over the next 1–2 weeks.

• Swollen glands: can take a few weeks to slowly shrink.

• Fatigue: commonly lingers for several weeks; around 1 in 10 people report tiredness for months, but long‑term serious complications are uncommon.

When to see a doctor

• If symptoms are not starting to improve after 2–3 weeks, or you feel worse rather than better.

• If you have trouble swallowing, breathing, or severe tummy/left‑side abdominal pain, which can be signs of rare complications.

• If fatigue is so strong after a couple of months that normal daily activities are very hard, as this may need further assessment.

Recovery and getting back to normal

• Rest, fluids, and avoiding overexertion for several weeks help recovery; doing too much too soon can prolong fatigue.

• Contact sports are often avoided for at least a few weeks because of a small risk to the spleen when it is temporarily enlarged.

• Most people can gradually resume school, work, and exercise as energy returns, increasing activity step by step rather than all at once.

If your symptoms or tiredness feel out of proportion to what is described here, or you are worried about how long glandular fever is lasting for you, a doctor or nurse can review you and check for other causes or complications.