How to Prevent the Transmission of Mononucleosis

Infectious mononucleosis, or mono, is a disease spread through saliva and other bodily fluids. It is therefore also known as “the kissing disease.” Mono is common in settings where individuals are in close quarters, such as college dormitories. Although less common, mono can also be spread through sexual contact, blood transfusions, and organ transplants.

Mono is usually caused by the Epstein-Barr virus (EBV), a type of herpes virus. Most commonly infecting young people, EBV can affect anyone. It's highly contagious and easily passed from person to person.

There is no vaccine to protect you against mono, and people can spread it before they know they have the illness. So, the best prevention is to avoid close contact with someone who may have the disease and to not share items like water bottles, toothbrushes, and eating utensils—anything that can spread saliva—with others.

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When Is Mono Contagious?

People who have been infected with mono are contagious as soon as they become infected. They can remain contagious for roughly six months.

It's important to note that even people without symptoms can transmit the virus. They may not know that they have mono, but they can still pass it on to someone else. Even when mono symptoms do show up, they may take a while to appear, about one to two months. This time before symptoms is referred to as the incubation period.

People also are contagious while they have symptoms, which can last from two to four weeks or even longer. Health experts aren't sure how long people with mono remain contagious after symptoms are gone, but it seems they can still spread the infection for months afterward.

Once you get mono, the virus remains in your body for life. It can resurface occasionally, and you can infect others during these times.

Prevention Steps

Since EBV is transmitted through close contact with others, the best way to prevent infection is by doing the following:

  • Avoid anyone you know who has mono.
  • Don’t kiss if you feel ill.
  • If you have penetrative sexual intercourse, use a condom to avoid transmission through semen.
  • Don’t share utensils and other items such as cups and glasses, hygiene products, or cosmetics.
  • Avoid sharing cigarettes.
  • If you care for young children, wash toys that they may have put in their mouths.

Boosting your immune system by eating a healthy diet and getting regular exercise and enough sleep is a good way to prevent not just mono, but any infection.

Good handwashing practices are also important and can reduce your risk of infection if you are exposed to the virus. Make sure to use antibacterial soap and wash your hands for at least 20 seconds. If you use hand sanitizer, choose one with at least a 60% alcohol content.

How Common Is Mono?

It is estimated that over 90% of Americans will get infected with the virus that causes mono by the time they are 35 years old. Most people who are infected with EBV don't actually develop mono.

When to See a Doctor

Typical symptoms of mono include:

  • Fatigue
  • Headache
  • Fever
  • Sore throat
  • Swollen lymph nodes
  • Skin rash
  • Swollen spleen (an organ in the upper-left side of the abdomen)

Concerning symptoms or worsening symptoms that may warrant a call to your healthcare provider include those that last for more than 10 days and the following:

  • Trouble breathing
  • Dizziness
  • Weakness in the extremities
  • Cognitive changes
  • Changes in vision
  • Fainting

This is not an exhaustive list of symptoms. It's best to call your healthcare provider if you are unsure if a symptom is problematic. Your healthcare provider will assess your symptoms and check for an enlarged spleen or liver. They may also order blood tests to check for antibodies to EBV and a high number of white blood cells, which is a sign of infection.

A rare but serious complication of mono is a ruptured spleen, which can happen if your spleen becomes swollen. A ruptured spleen requires immediate medical attention. It is wise to avoid vigorous contact sports while you are infected with mono.

Mononucleosis Doctor Discussion Guide

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A Word From Verywell

It's difficult to identify who has been infected with mono, especially when the affected individual doesn't show symptoms. Therefore, it can be difficult to prevent mono because the best way to do that is to avoid close contact with someone who has it.

Still, it's good to stay healthy and practice good hygiene, including not sharing personal items, to minimize your chances of getting infected. If you do become sick with mono, you will be able to recover with plenty of rest and fluids. If you experience any unusual symptoms, contact your healthcare provider right away and find out whether mono or something else is causing your symptoms.

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Article Sources
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  1. Ginsburg CM, Henle G, Henle W. An outbreak of infectious mononucleosis among the personnel of an outpatient clinic. Am J Epidemiol. 1976;104(5):571-575. doi:10.1093/oxfordjournals.aje.a112332

  2. Kids Health. How long is mono contagious? Updated January 2020.

  3. The Boston Public Health Commission. Mononucleosis.

  4. Cleveland Clinic. Mononucleosis. Updated August 3, 2020.