Epstein-Barr Virus in Chronic Fatigue Syndrome

The Epstein-Barr virus (EBV) is a member of the herpesvirus family and one of the most common human viruses. It has long been tentatively connected to chronic fatigue syndrome (ME/CFS), with some researchers saying it's an important causal factor while others say it's not involved with this disease at all.

A woman touching her throat
Image Source / Getty Images

Those who believe it is connected often talk about reactivation. All herpesviruses stay in your system forever but generally remain dormant most of the time. When they do become active, specialized cells in the immune system, including B-cells and T-cells, typically don't have a problem knocking them back down again.

Most people aren't even aware that this process is going on. That's because B- and T-cells, in a healthy immune system, remember the virus and can rapidly assemble an army of antibodies to keep it in check.

If the immune system isn't working correctly, though, it could theoretically allow the virus to gain a foothold at levels that once again make you sick. When that happens, it's called reactivation.

Evidence of Reactivation

We do have some evidence to back up the hypothesis of EBV reactivation in some cases of ME/CFS. Research published in 2014 shores up that hypothesis.

In this study, scientists found evidence that the B- and T-cells of many people with this disease were unable to remember EBV, meaning a reactivated virus would be better able to thrive, reproduce, and cause symptoms.

Researchers found this impaired cellular memory in the immune systems of 76 percent of the more than 400 study participants. That's an impressive percentage.

Along with showing what may cause and sustain some cases of ME/CFS, researchers say this work could lead to a long-sought diagnostic marker. (Currently, we have no objective test for diagnosing ME/CFS, so it remains a diagnosis of exclusion.)

More About the Epstein-Barr Virus

EBV is a nasty bug. It's best known for causing infectious mononucleosis, which is frequently called mono or the "kissing disease." Symptoms of mono include:

  • Severe fatigue
  • Sore throat
  • Headache
  • Fever
  • Muscle aches
  • Swollen lymph nodes
  • Sensitivity to light
  • Shortness of breath

Recovery from mono is known to take a long time, and recurrences are marked by extreme fatigue.

Some researchers have long believed it's no coincidence that those are also symptoms of ME/CFS. However, a large portion of the population carries EBV in their bodies and only a small number of those people develop ME/CFS. That has confounded attempts to explain how EBV could contribute to the illness.

This study appears to overcome that problem, though, providing an answer to that question. It doesn't answer questions about why some people's immune systems seem to be blind to this particular virus, though. That's a topic for future research, as is finding a way to fix the blindness.

Previous EBV Studies

Other studies have shown that a significant number of juvenile ME/CFS cases come soon on the heels of mono, and many adolescents whom doctors deem unrecovered from mono fit the ME/CFS diagnostic criteria. It seems that the harder EBV hits, the more likely it is to cause prolonged illness.

In addition to mono, EBV is linked to certain types of cancer, which could explain the higher incidence of cancer-related illness and death that some ME/CFS experts report that they've observed. EBV may also play a role in multiple sclerosis. Some research also suggests it can mimic acute leukemia.

None of this is conclusive, though. We still have a long way to go when it comes to EBV or any virus as a potential cause of ME/CFS.

A Word From Verywell

With this new discovery of impaired cellular memory, we may have filled a significant gap in knowledge about how EBV could be triggering ME/CFS and contributing to on-going symptoms.

While more work is needed to verify this study, it could prompt more doctors to prescribe antiviral medications (such as valacyclovir or valganciclovir) for ME/CFS patients with high EBV levels.

Chronic Fatigue Syndrome Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Woman
4 Sources
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.
  1. Loebel M, Strohschein K, Giannini C, et al. Deficient EBV-specific B- and T-cell response in patients with chronic fatigue syndrome. PLoS One. 2014 Jan 15;9(1):e85387. doi:10.1371/journal.pone.0085387

  2. Agliari E, Barra A, Vidal KG, Guerra F. Can persistent Epstein-Barr virus infection induce chronic fatigue syndrome as a Pavlov reflex of the immune response?. J Biol Dyn. 2012;6:740-62. doi:10.1080/17513758.2012.704083

  3. Katz BZ, Shiraishi Y, Mears CJ, Binns HJ, Taylor R. Chronic fatigue syndrome after infectious mononucleosis in adolescents. Pediatrics. 2009;124(1):189–193. doi:10.1542/peds.2008-1879

  4. Chhabra P, Law AD, Sharma U, et al. Epstein-barr virus infection masquerading as acute leukemia: a report of two cases and review of literature. Indian journal of hematology & blood transfusion. 2014 Mar;30(1):26-8. doi:10.1007/s12288-012-0207-2

By Adrienne Dellwo
Adrienne Dellwo is an experienced journalist who was diagnosed with fibromyalgia and has written extensively on the topic.