Can you get mono twice? It's very rare — here's why
- Most people will not be able to get mono twice in their life.
- That's because once you're infected with the virus that causes mono, it remains inactive in your body.
- However, those who are immunocompromised may be at a higher risk for the virus reactivating, and experiencing mono symptoms more than once.
- This article was medically reviewed by Kristine Arthur, MD, an internist at MemorialCare Medical Group in Laguna Woods, CA.
Infectious mononucleosis, or mono for short, is spread by the Epstein–Barr virus (EBV), a member of the herpes family, through saliva or respiratory droplets.
More than 90% of people worldwide are infected with EBV. The virus will remain inactive for many of these people, and they'll never have any symptoms of mono.
However, at least 25% of young people who get infected with EBV will develop symptoms of mono, according to the Centers for Disease Control and Prevention (CDC). But there's some good news — if you get mono, it's almost impossible to get it again. Here's why.
Can you get mono twice?
Once you've had mono, it's extremely unlikely that you'll get it again months or even years later.
When you've been infected with EBV, it remains in your throat and blood cells for the rest of your life — but is usually latent, or inactive. Your immune system produces antibodies in your blood that help protect you against a recurrence of EBV.
"This will give you permanent immunity from catching the virus again," says Dimitar Marinov, MD, an assistant professor in the department of hygiene and epidemiology at Medical University in Varna, Bulgaria. "That's the reason why you cannot get mononucleosis twice."
However, EBV may periodically reactivate in your body, leading to higher levels of the virus in your saliva. Even if EBV does reactivate, there are usually no symptoms of mono in otherwise healthy people, Marinov says.
However, you could possibly still spread EBV to others, regardless of how long it's been since you were first infected, the CDC notes. That's why mono can be contagious long after you've displayed symptoms.
People with weak immune systems are more likely to get mono twice
However, if you have a weakened or suppressed immune system, also known as being immunocompromised, then you're more at risk of getting mono more than once. If you have the following conditions, you are more likely to show symptoms of mono if EBV reactivates.
- People with autoimmune diseases such as lupus, multiple sclerosis, or rheumatoid arthritis
- People taking immunosuppressant medications, such as corticosteroids like prednisone, to treat autoimmune diseases
- Cancer patients
- People with AIDS
Although it is unclear what can trigger a reactivation of EBV, it may be due to an activation of B cells — a type of white blood cells in your immune system — in response to an unrelated infection.
EBV invades your B cells and makes your body produce an excessive number of lymphocytes, the round white blood cells in your lymph tissues, and produce fewer neutrophils, the white blood cells that boost your immune system's ability to fight infection.
In very rare cases, an EBV infection may develop into chronic active EBV (CAEBV). Instead of going dormant, EBV remains active and can lead to serious complications such as a weakened immune system, lymphomas, or organ failure. The only current cure for CAEBV is hematopoietic (blood cells) stem cell transplantation.
People from Asia, South and Central America, and Mexico are more at risk for CAEBV, and it's mostly caused by genetic factors. "There are people with genetic variations in their immune cells who are more susceptible to a CAEBV infection," Marinov says.
Other common illnesses that you might mistake for mono
It's rare that you'll actually get mono twice. So, if you've already had mono once, and you think you're getting it again, it's more likely that you actually have another illness with similar symptoms, such as strep throat or influenza.
Mono symptoms usually begin four to six weeks after you've been infected with EBV. The symptoms typically last from two to six or more weeks, which is much longer than they usually last for other viral infections.
Unlike mono, the common flu is caused by an influenza virus that can be transmitted not just through saliva, but through the air and by touching contaminated objects.
The bottom line
If you've already had mono, and think you may have it again, check with your doctor, who can determine if that's the case — or if you just have another common illness, like strep throat or influenza.
However, in some cases, serious conditions can also display symptoms similar to mono. This includes hepatitis B, a virus that causes inflammation of the liver and has additional symptoms besides those for mono, such as dark urine and yellowing of your skin. You should see a doctor right away if you have these symptoms.