An Overview of Epstein-Barr Virus

A Common Infection That Sometimes Causes Complications

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Epstein-Barr virus (EBV) infects most of the world’s population—around 95% of adults. Although infection with the virus often doesn’t cause symptoms at all, it can also lead to mononucleosis, which can cause symptoms like fever and fatigue.

EBV also increases the risk of certain cancers, and it seems to play a role in some autoimmune and other medical conditions. The virus is named for Epstein and Barr, who discovered it in 1964.

What Is the Epstein-Barr Virus?

Epstein-Barr virus, like other viruses, is a microscopic agent that can only survive and replicate by infecting a host. EBV is grouped together with other similar viruses categorized as double-stranded DNA viruses, because of their specific structure.

EBV is in the herpes family of viruses, and it is sometimes referred to as human herpesvirus 4. However, it doesn’t cause the same symptoms as a couple of other viruses in this family that can cause sores around the lips or genitals.

The virus often first attaches to and infects certain cells that line your mouth. From there it spreads mostly to certain cells of the immune system, particularly a type known as B cells.

Active Versus Inactive Infections

Infection with EBV includes an active phase and an inactive, latent phase. When a person is first infected, the virus is actively multiplying and spreading through the body. In the case of EBV, a person might or might not have symptoms from the virus during this time.

Later comes the inactive phase. Here, the virus still can be found in some cells of your body, but it isn’t actively dividing or causing any symptoms.

The virus inserts some of its own DNA into your DNA, which might or might not cause problems down the line. Your body hasn’t completely gotten rid of the virus. That is what happens with EBV.

Sometimes, an inactive virus becomes active again. That can happen in other infections, like in hepatitis B infection, and it can also happen in EBV. Usually, people don’t experience symptoms during this reactivation phase, but they are much more likely to spread the virus during this time.

Reactivation of the virus is particularly a concern for people who have impaired immune systems, who are more at risk from some of the potential complications from EBV, like certain cancers.

EBV Infection Symptoms

Many people get infected with EBV and never experience any symptoms from it. This is called “asymptomatic infection.” When people get infected in childhood—as happens most commonly—EBV often causes no symptoms at all.

Some children get mild symptoms, like fever, that aren’t distinguished from other normal childhood illnesses. Middle-aged adults first infected with EBV often don’t have any symptoms either.

However, infection with EBV can sometimes lead to a syndrome of symptoms called mononucleosis, sometimes called “mono” for short. This most commonly occurs when people become infected with EBV during adolescence or early adulthood. It might take several weeks after infection before you start showing symptoms.

Someone with mononucleosis might have symptoms like the following:

  • Severe sore throat
  • Swollen lymph nodes
  • Swollen tonsils
  • Rash
  • Fever
  • Fatigue
Image of arm showing an Epstein-Barr Virus rash

Reproduced with permission from ©DermNet NZ 2022

Most of these symptoms go away within a few weeks. However, fatigue from mononucleosis can be debilitating, and it may last for weeks or months.

Mononucleosis also occasionally causes a person’s spleen to enlarge. Very rarely, this can lead to a serious problem—spleen rupture. Mononucleosis also sometimes also causes other very rare but serious symptoms, like encephalitis.

It should be noted that although EBV is the most common virus that causes mononucleosis, other viruses, such as CMV, can sometimes cause it as well.

No treatment currently exists to directly treat mononucleosis. Pain medications, hydration, and rest are the main treatment approaches.

Chronic EBV

Extremely rarely, the EBV virus doesn’t go into its inactive phase, instead staying active inside the body. This causes a serious syndrome called chronic active Epstein-Barr virus disease (CAEBV).

It can cause symptoms like fever, enlarged spleen, and liver disease. CAEBV can also impair the immune system, making people much more prone to serious infections and lymphomas.

Complications of EBV Infection

There are complications linked to EBV infection.

Cancer Risks

EBV infection also increases one’s risk of getting certain cancers, at least for a limited time after getting infected. Some people are familiar with human papillomavirus (HPV), which increases the risk of cervical cancer and some other cancer types. Similarly, infection with EBV increases the risk of certain cancers.

For example, if you get mononucleosis from EBV, you have an increased risk of getting Hodgkin lymphoma for the next 10 years or so. A person’s risk of getting Burkitt lymphoma is also increased for a few years after getting mononucleosis from EBV.

Other types of cancer associated with EBV include stomach cancers and nasopharyngeal carcinoma. EBV can also cause an aggressive cancer called posttransplant lymphoproliferative disorder in people who have received an organ or stem cell transplant.

Some of the trouble from EBV comes from the fact that the body never really gets rid of it. The virus inserts its DNA inside the host and can trick the body into making copies of viral proteins. Some of these proteins affect key genes already in the DNA. Through this, they ultimately play a role in cancer development in some people, though not in the large majority of people who get infected.

You might be told that your cancer is EBV positive. That means that EBV and its proteins can be found in the cancerous cells of your body. If that’s the case, it’s likely the virus played a role in causing your cancer.

It’s not clear why some people who have EBV develop cancers while most others don’t. Many factors are probably involved, including genetics and the presence of other infections. For example, lymphomas that have the EBV proteins are more common in areas of the world where malaria is prevalent.

People who are immunocompromised are particularly prone to developing cancers related to EBV. For example, this applies to people with impaired immune from HIV or from an organ or stem cell transplant.

As of now, we don’t have any treatments that specifically target cancers that have EBV as a partial cause. However, this might change in the future, as we develop therapies that specifically address EBV’s role.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a condition of extreme, prolonged fatigue that can’t be explained by another medical condition.

For many years, some researchers have proposed a link between chronic fatigue syndrome (CFS) and infection with EBV and/or potentially other viruses, though the issue is not yet settled. This idea has been an especially popular one for practitioners of alternative or complementary medicine.

Some studies have shown differences in how the immune system is functioning in people with CFS. We definitely know that mononucleosis can cause symptoms of extreme fatigue that may last for weeks or months, and that its symptoms can appear similar to some of those that appear in chronic fatigue syndrome.

Some researchers have proposed that the disease might sometimes be triggered by initial infection with EBV, particularly if this happens in adulthood. However, there is much about this that researchers are still working to understand. If it does play a role, it probably isn’t involved in all cases of CFS. And even if an infection triggers CFS in some people, factors other than EBV may be important too.

Autoimmune Disease

More recently, scientists have discovered a potential link between EBV and autoimmune diseases such as rheumatoid arthritis, lupus, Sjogren’s syndrome, and multiple sclerosis.

The data on this are not yet clear, and scientists are not exactly sure what role the virus might be playing. It may be that the immune response to EBV plays a role in the body’s inflammatory response to its own cells in autoimmune disease.

Some of the proteins made by EBV seem to interact with specific genes known to be associated with increased risk of certain autoimmune diseases. However, no therapies targeting EBV currently exist in treating these various conditions.


Depending on the medical context, you might need to have tests to check to see if you have been infected with EBV, either recently or in the more distant past. An older test sometimes used to diagnose mononucleosis, the Monospot test, is no longer recommended by the CDC because of poor reliability.

However, in some situations you might need to get one or more antibody tests for EBV. These antibody tests are not usually needed to diagnose mononucleosis, but they might be necessary if you have an unusual case, or if you have another health problem related to EBV infection.

For example, they might be important if you are getting an organ transplant. However, most people will never need testing for EBV.


Most commonly, EBV is spread by sharing saliva. For example, you can get it from kissing or by sharing drinks or food with someone who already has EBV. Because EBV is spread so easily through kissing, it got its nickname as “the kissing disease.”

However, EBV can spread in other ways too. You might get it if you use an object that an infected person recently used, such as a toothbrush. You can get it through sexual contact, blood transfusions, and organ transplants as well.

You are most likely to spread the virus if it is in its active phase. People who get EBV may spread it for weeks before they have symptoms. Or they may be actively spreading it, even though they never go on to get any symptoms at all.


Standard infection control measures can decrease spread of the virus. This means things like not sharing food or kissing someone with mononucleosis, covering coughs, and frequently washing your hands.

Unfortunately, most adolescents and young adults don't know whether they have already been infected with EBV or not. So it's wise to be cautious around someone who has mononucleosis or who has had it in the past several months.

However, because it is so common in the population, avoiding infection with EBV is nearly impossible over the course of one’s lifetime. Many people shedding the virus won't have any symptoms. And it may be more desirable not to try to prevent virus infection during childhood, because infections then are usually mild.

No vaccine is currently available to prevent infection with EBV. However, this is still an active area of research. If successful, vaccination for EBV might one day be included as part of standard childhood vaccinations, theoretically decreasing risk for medical conditions related to EBV.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Ruth Jessen Hickman, MD
Ruth Jessen Hickman, MD, is a freelance medical and health writer and published book author.