The Three Stages of Mononucleosis

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Mononucleosis, or mono, is a contagious illness that has three distinct stages. These phases can impact each infected individual differently.

Mono is typically caused by a virus called Epstein-Barr, but 10% of cases are caused by other viruses. Having the virus that causes mono is very common, but only a small percentage of people will actually get mono.

This article explores the three phases of mono. It will also explain how long mono lasts, treatment options, general progression, and its long-term effects.

Stages of Mononucleosis - Illustration by Danie Drankwalter

Verywell / Danie Drankwalter

What Are the Stages of Mono?

A mono infection generally has three distinct stages. In each stage, the infection can cause different symptoms and health concerns.

Stage 1: Prodrome

The prodrome, or earliest, stage of mono is when symptoms begin to appear. The length of time it takes to start showing symptoms after a person is infected, known as the incubation period, is about four to six weeks. This can make it difficult to know when the infection began.

Symptoms of mono during this phase usually last three to five days and include:

  • Fatigue, or low energy
  • Feeling off or uncomfortable
  • No appetite
  • Sore throat

It is possible to have the mono infection without symptoms. Those under the age of 10 may not show any signs of mono, or may experience very mild symptoms.

Stage 2: Acute Phase

During the second, or acute, phase of mono, symptoms may worsen. Symptoms may include:

With severe cases of mono, individuals may experience liver and spleen damage. Other serious, but rare concerns may include:

  • Jaundice, which occurs when a substance called bilirubin builds up and causes the skin and whites of the eyes to yellow
  • Liver failure
  • Peritonsillar abscess, which is an infection in the throat
  • Encephalitis, which is inflammation in the brain
  • Pleural effusion, which is when fluid builds up in the lungs

Not everyone will experience every symptom. Keep in mind that symptoms could also appear at different times over the course of the infection.

Stage 3: Convalescent Phase

The convalescent, or last, phase of mono occurs when a person starts to recover. This stage can last anywhere from three to six months.

Typically, most symptoms have resolved by this point. However, some people may still feel weak and tired. During this time, if someone has an inflamed or enlarged spleen, they should avoid any physical activities that could lead to spleen rupture.

How Is Mono Treated?

Currently, there is no medication or vaccine that can prevent or cure mono. This illness is fought off by the immune system. To help with recovery:

  • It's important for someone who has mono to rest and get plenty of fluids.
  • Over-the-counter or prescription medications may help with symptoms such as pain and fever. However, acetaminophen should be used with caution because of the increased risk of liver complications.
  • Medications that help with inflammation may be used.

In severe cases of mono, different treatments may be needed. With some cases, doctors may prescribe a steroid medication called a corticosteroid.

Mono is spread through bodily fluids. The best ways to prevent mono include:

  • Making sure whoever you share bodily fluids with doesn't have mono
  • Not sharing drinks and food
  • Not sharing personal items
  • Practicing good hygiene

How Quickly Does Mono Progress?

The timeline from the initial onset of mono to a full recovery can differ from person to person. In the first four to six weeks after a person gets mono, they may not even know they have it. This is because mono has a long incubation period.

When symptoms begin to appear in the first phase, they can last about three to five days. These symptoms may be so mild that people don't notice them.

As symptoms worsen in the next phase, mono can continue for two to six weeks. Then the recovery period can last up to six months. From start to finish, a case of mono can last up to 10 months.


How long mono lasts can vary from person to person. On average:

  • Mono has an incubation period that lasts from four to six weeks.
  • The prodrome phase can last between three to five days.
  • The acute phase can last up to six weeks.
  • The recovery period can last up to six months.

What Are the Long-Term Effects of Mono?

Studies have shown that Epstein-Barr virus (EBV) may be linked to Burkitt’s lymphoma and Hodgkin lymphoma, which are types of cancer. Mono has also been associated with an increased risk of developing autoimmune diseases like multiple sclerosis.

In rare cases, people with mono may develop a chronic active Epstein-Barr virus (CAEBV) infection. This can occur in those with a first-time infection or in those who have already recovered from the illness if the virus reactivates within the body.


Mono is a contagious illness that is usually caused by the Epstein-Barr virus. Mono has three stages: a prodrome, an acute stage, and a convelescent (recovery) stage.

Because mono has a long incubation period, it can be difficult to determine when the illness actually began. On average, the prodrome phase lasts three to five days, while the acute phase can last up to six weeks. The final recovery stage can go on for up to six months. In general, mono can impact an individual for up to 10 months.

Mono has been linked to certain cancers and autoimmune disorders. It is also possible to develop chronic Epstein-Barr virus, even with a first time mono infection.

While there isn't any specific treatment for mono, there are ways to support recovery. Drinking lots of fluids, getting plenty of rest, and taking medications for pain and fever can be helpful.

A Word From Verywell

The virus that can cause mono is extremely common. Chances are, you and most of the people you know may get it at some point without ever knowing it. However, only a small amount of people will actually get full blown mono.

Recovering from mono can take quite a while. Keep in mind that the majority of people who have mono recover fully with plenty of rest and fluids. Be sure to reach out to your doctor if you are showing any signs of mono, or have been in contact with someone who has the infection.

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9 Sources
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  1. Cleveland Clinic. Mononucleosis (mono).

  2. Becker JA, Smith JA. Return to play after infectious mononucleosis. Sports Health. 2014 May;6(3):232-238. doi:10.1177/1941738114521984

  3. Stock I. Infectious mononucleosis--a “childhood disease” of great medical concern. Med Monatsschr Pharm. 2013;36(10):364-368.

  4. Centers for Disease Control and Prevention. Epstein-Barr virus and infectious mononucleosis.

  5. Johns Hopkins Medicine. Infectious mononucleosis.

  6. Zhang L, Zhou P, Meng Z, et al. Infectious mononucleosis and hepatic function. Exp Ther Med. 2018 Mar;15(3):2901-2909. doi:10.3892/etm.2018.5736

  7. Herold J, Grimaldo F. Epstein-Barr virus-induced jaundice. Clin Pract Cases Emerg Med. 2020 Jan 21;4(1):69-71. doi:10.5811/cpcem.2019.10.45049

  8. Balfour HH, Dunmire SK, Hogquist KA. Infectious mononucleosisClin Trans Immunol. 2015;4(2):e33. doi:10.1038/cti.2015.1

  9. Kimura H, Cohen JI. Chronic active Epstein-Barr virus disease. Front Immunol. 2017 Dec 22;8:1867. doi:10.3389/fimmu.2017.01867