The way mono works in the body is tricky, so lots of people are confused about
how long it is contagious. If you get mono, the
stays in your body for life. That doesn't mean that you're always
. But the virus can surface from time to time and risk infecting someone
Here's how it works:
Mono is short for mononucleosis.
It's usually caused by an infection with the Epstein-Barr virus (EBV).
People who have mono can be contagious from the time they first become infected.
But they may not know that they have the virus. It takes a while for mono symptoms
(like tiredness, fever, muscle aches, headache, or sore throat) to show up — about
4 to 7 weeks, in fact. This is called the incubation period.
To make things even more confusing, some people can carry the virus without ever
getting any mono symptoms. Even if they don't know they have the infection, they can
still pass it to others.
Mono needs to run its course naturally. Symptoms may last 2 to 4 weeks, and some
people feel tired for several weeks longer. That's why it's important to take care
of yourself and get lots of rest.
Health experts aren't sure how long people with mono stay contagious after symptoms
are gone. They believe that people can spread the infection for many months after
that — some studies show as long as 18 months. Then, the virus stays dormant (inactive)
in the body for the rest of a person's life.
Sometimes the dormant virus can "wake up" and find its way into a person's
saliva (spit). That person might not feel ill or show any mono symptoms, but can spread
the virus to other people. So there's a very small chance that people who have had
mono in the past can pass it to others, even when they feel OK.
The bottom line is that it's hard to prevent mono from spreading.
Because EBV is so sneaky, infections are common. About 95% of people are infected
with the virus by the time they are adults. Viruses like EBV are one reason why doctors
urge everyone to wash their
hands well and often. It's the best way to keep germs at bay.