Is Mono Contagious?

By Frank DiVincenzo, MD
Medically reviewed checkmarkMedically reviewed
April 12, 2022

Mono, or mononucleosis, is a very common—and contagious—virus.

Many people wonder just how contagious it really is, though—and for how long an infected person remains contagious and able to spread the disease. 

While mono is generally not as serious as other, more prevalent ailments like influenza or the common cold, some people do suffer from complications that disrupt their regular lives. 

In this article, we’ll explore what mono is, how mono spreads, and how long you need to take precautions to contain it if you have an active case.

We will also explore ways you can curb the spread of mono to ensure your health and safety and that of those around you. 

Lastly, we’ll advise you on when to see a healthcare professional and how you can reach out to K Health for help whenever you need it.

What is Mono?

Also known as the “kissing disease,” infectious mononucleosis (or mono for short) is a contagious infection most commonly caused by the Epstein-Barr virus, or EBV.

This member of the human herpes virus family is present across the globe and can affect people of all ages and lifestyles. 

Mono can be contracted at any time of the year and is not dependent on the climate or season. 

Mono is a very common virus and spreads predominantly through bodily fluids like saliva.

More than 90% of adults have antibodies, which means they were likely infected years earlier as teens or adolescents.

Many people carry the virus in their bodies without ever even realizing it.

Once your body catches mono, it will be present in your system forever.

However, there’s only cause for concern once the virus is no longer dormant and you start feeling symptoms.

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How is Mono Spread?

Mono earned the moniker “the kissing disease” because of how easily it spreads through—you guessed it—kissing.

However, the name is misleading as mono can also pass from person to person when sharing any objects that have been infected (like silverware, for example). 

Mono can also be spread through vaginal, cervical, and penile secretions during sexual contact. In these cases, mono is considered a sexually transmitted disease (STD). 

Viruses like mono can also spread through organ transplants, blood transfusions, and any other instance where an infected bodily fluid like blood, saliva, or semen comes in contact with another person.

Additionally, mono can spread when an infected person coughs and sneezes near others. 

Exposure to mono is normal, and most children are exposed to EBV and mono at some point while growing up or in young adulthood.

How Long is Mono Contagious?

While common mono symptoms might only last a few weeks or up to a month, the virus can remain contagious and be passed on for several months after symptoms subside. 

Because the virus stays in your body for life, many people fear that they will always be contagious.

This is not the case.

That said, if you show symptoms such as a sore throat, fever, fatigue, and headaches, you might want to isolate yourself, even if you don’t know what you are sick with yet.

This will help reduce the chances of passing it on if you do actively have mono.

Incubation Period

If you come into contact with someone with mono, your body can take up to a few weeks to develop common symptoms.

If you learn of an exposure, isolate yourself for an incubation period of up to six weeks to curb the disease from spreading.

Contact your healthcare professional to conduct a blood test that will conclusively show if you have the Epstein-Barr virus.

Active Infection Period

The active infection period is when the virus is alive in your body, and you will be contagious during this period.

If you start showing symptoms, then you must isolate yourself immediately.

The Centers for Disease Control and Prevention (CDC) says that some mono symptoms can last up to six months or more—however, most cases don’t last that long and will run their course within a month.

Reach out to your doctor or one of our healthcare experts for advice on what you can do if symptoms do not go away after three months.

Oral Shedding

Some studies show that while an infected person’s blood clears the virus fairly quickly, there might still be higher traces of it in their saliva. 

The long-term oral shedding of mono means there is a small chance that the virus can spread even after you’ve physically recovered.

While this is not always in your control, take routine sanitization precautions like washing your hands regularly and refraining from touching others when not required.

Risks of EBV Reactivation

While you may always have mono living dormant in your body, the risk of EBV reactivation is higher for those with weaker immune systems and chronic autoimmune diseases. 

Reducing Risk of Transmission

Although there is no vaccine to protect against infectious mononucleosis, there are certain precautions you can take to reduce the risk of transmission. 

Here are a few:

  • Keep yourself protected by not kissing or sharing drinks and utensils or personal items (like toothbrushes and razors) with people who have mono
  • Maintain good hygiene and handwashing practices 
  • Be consistent with a clean and healthy lifestyle
  • Keep a safe distance from anyone showing signs of mono like fever, cough, or swollen lymph nodes
  • Always practice safe sex by wearing a condom or other barrier method of protection if you are not in a monogamous relationship

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When To See a Medical Provider

If you’re experiencing symptoms of mono, make an appointment with your doctor or healthcare professional to get a formal diagnosis. 

Once you are diagnosed with mono, you will probably not need to see your doctor again.

Most symptoms of mono can be treated from home with plenty of rest, a nutritious diet, and lots of fluids.

Your symptoms should begin to ease within 2-4 weeks; however, if they don’t, or if you think you feel worse, see your doctor immediately.

Mono may also cause your spleen to enlarge. If you have mono and suddenly experience intense pain in the upper left side of your abdomen, call 911 immediately.

How K Health Can Help

Mono is a contagious disease so if you’re experiencing symptoms, isolate yourself and reach out to a doctor to get a diagnosis immediately. 

Did you know you can access online urgent care with K Health?

Check your symptoms, explore conditions and treatments, and if needed, text with a healthcare provider in minutes. 

K Health’s AI-powered app is based on 20 years of clinical data.

Can I be around someone with mono?
Even though mono is not as contagious as other infections, you need to take certain precautions to prevent it from spreading. You can be around someone with mono, but avoid kissing and touching them. Refrain from sharing utensils and other objects that might be in contact with their bodily fluids. If you would like to be around someone with mono, wear a mask to cover your mouth and nose and wash your hands immediately after parting ways with them.
How easy is it to get mono from someone?
It is quite easy to get mono from someone if you have kissed them or touched something that came in contact with their saliva or other body fluids. Mono can also be passed through sharing of lipstick, cutlery, and utensils.
When is mono most contagious?
Mono is most contagious within the first 2-4 weeks of a person experiencing symptoms. It is advisable to remain cautious for several months after symptoms subside, as mono can still be passed on to others through saliva.
Can you kiss someone with mono and not get it?
Because mono spreads through any trace of saliva, kissing is not the only way to pass the disease, although it is the most common. Droplets from an infected person’s saliva will contain the mononucleosis virus, so it is unlikely that you will avoid catching it if you kiss someone who has it. Even with dry kissing and kissing after completely sanitizing the mouth area, there is a chance that traces of mono remain on the skin.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Frank DiVincenzo, MD

Dr. Frank DiVincenzo has been a physician with K Health since 2020. He grew up near Chicago, Illinois, but left the big city to go to college and then attend graduate school in Missouri. He received a Bachelor of Science in Mathematics and a Master of Science in Microbiology before graduating from the University of Missouri–Columbia School of Medicine.

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