Epstein-Barr Virus

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Epstein-Barr Virus

Question:

Is the Epstein-Barr virus contagious?

Answer:

Yes. The Epstein-Barr virus is so contagious that practically every adult is infected with it.

Nearly 90% of people in the U.S. have become infected with the virus by age 20. Not only that, but once we get infected with this virus, it remains permanently inside us for the rest of our lives. It lives in some of our white blood cells, in cells in our mouth and throat, and possibly in other parts of the body. Fortunately, though, this virus does not often cause long-term health problems. So if you have been told that you are infected, join the club: most of us are (I am), and very few of us ever suffer any consequences.

The virus is often present in our saliva. Most of the time, the virus is passed from one person to another by exposure to saliva, such as during kissing or possibly by exposure to someone's cough.

The Epstein-Barr virus can cause a variety of temporary illnesses. The most common illness is infectious mononucleosis (often called just "mono"). Being infected with the virus may sometimes contribute to causing certain cancers of the white blood cells and lymph glands, or cancers of the mouth, but this is pretty rare. Recent evidence shows that being infected with the virus may contribute to some cases of multiple sclerosis. And in people with an extremely rare kind of immune deficiency, the virus can cause diseases of many different organs.

So the bottom line is that most human beings are infected with the Epstein-Barr virus. Some of us get a temporary illness like mono when we are first infected. But most of us never get a long-term illness from our infection. It lives inside us, causing no problem.

Anthony Komaroff, M.D., is professor of medicine and editor-in-chief of Harvard Health Publications at Harvard Medical School. Dr. Komaroff also is senior physician and was formerly director of the Division of General Medicine at Brigham and Women's Hospital. Dr. Komaroff has served on various advisory committees to the federal government, and is an elected Fellow of the American Association for the Advancement of Science.

Last updated:	July 20, 2009