EBV, mono’s primary driver, is extremely common — so much so that not having been infected with EBV is much rarer than being infected by it at some point. As many as 90 to 95 percent of adults have been infected with EBV, says Eric Johannsen, MD, an associate professor of infectious disease at the University of Wisconsin School of Medicine and Public Health in Madison, who specializes in EBV. (1) Anyone can get mono at any age — even young children — but it’s most prevalent in teens and college-aged young adults, and tends to be more severe the older you get. (2,3,4) As many as 25 percent of teens and young adults who become infected with EBV develop infectious mononucleosis. (3) When someone gets mono, it can be debilitating. The good news is that most people recover completely after resting in about two to four weeks without long-term complications, though some people may feel tired and not be able to fully resume their normal activities for several more weeks. (1,2,3,6) How do you know if you have mono? Here are some common signs: (1,2,3)
Sore throatSevere fatigueFeverBody achesSwollen lymph nodes in the neck and armpitsEnlarged spleen or liverHeadacheLoss of appetiteRash
Symptoms typically appear anywhere from four to six weeks after someone gets infected with EBV. Doctors aren’t sure why, but symptoms tend to be much less severe in younger kids. Unlike teens and adults who typically feel very ill and are knocked off their feet by mono, younger children may only experience a mild fever or feel tired — or they may not have any symptoms at all. “In children as young as age 3, 4, or 5, it may be very benign,” says Octavio Ramilo, MD, chief of infectious disease at Nationwide Children’s Hospital in Columbus, Ohio. (1,7) “We still don’t understand how the immune system changes in life,” Dr. Ramilo says. RELATED: Everything You Need to Know About the Cold and Flu If you’re experiencing any of the aforementioned mono symptoms and they persist for more than a few days, especially if any are severe or not showing signs of getting better, it’s a good idea to see your doctor, who can test you for mono and rule out other illnesses. (7) Whether you’ve been diagnosed with mono or not, these are the symptoms that warrant an immediate call to your doctor or seeking emergency care right away:
Sudden and sharp pains in the upper left side of your abdomen — this could be an indication that your spleen may be ruptured and you need to seek medical attention right away. This danger is a key reason why doctors urge anyone with mono to avoid any sports or activities that require any physical contact or strain.Difficulty breathing or swallowing (caused by enlarged tonsils)Decreased urine output (a sign of dehydration)Symptoms of mono that get worse or do not go away after two to four weeks (4,9)
RELATED: All About Symptoms of Strep Throat and How to Get Diagnosed But there are telltale signs that point to mono. For instance, if someone still has a sore throat, fever, and rash by day seven, it’s likely a sign that they have mono rather than a cold or strep, says Ramilo. “For doctors, the most common indicator of mono is fatigue,” says Hank Balfour, MD, professor of laboratory medicine and pathology, as well as pediatrics, at the University of Minnesota Medical School in Minneapolis. Another indication that the infection may be mono versus a cold or flu is when the symptoms occur. People tend to come down with a cold or the flu in the cooler months, says Dr. Balfour. But people get mono all year long, he adds. RELATED: The Ultimate Guide to Winter Wellness Another condition that often gets confused with mono is chronic fatigue syndrome (CFS). Both conditions share symptoms such as extreme fatigue, muscle aches, and sore throat. But one of the most obvious distinguishing features is that the symptoms of mono do not recur for most people, whereas CFS symptoms are, as the name indicates, chronic. Mono symptoms do linger longer than a cold or the flu typically would, but they certainly aren’t chronic, Ramilo says. And while mono doesn’t cause CFS, some research suggests having had infectious mononucleosis increases the risk of developing CFS in adults and adolescents, Johannsen says. (10) Still, knowing how EBV spreads (and how mono spreads) can help you take the right steps to avoid getting the infection. EBV is transmitted through saliva (hence the name “kissing disease”), and it can stay in the saliva of people who’ve been infected for months, though how long it stays in the saliva and how long someone with the virus is contagious can vary. “We don’t know how much virus is necessary to transfer from person to person,” Balfour says. It’s important to know that someone can appear fine (and may not have a mono infection or any symptoms yet or at all), but can still shed the virus in their saliva. It can take about four to seven weeks for symptoms to show up after someone’s been infected with the virus, and symptoms tend to last for another two to four weeks — and a person is contagious through all of this time. (12) Research has not yet confirmed how long a person who’s had mono remains contagious after symptoms have disappeared. “Unlike a cold sore, you don’t know when someone [with mono] is shedding and infectious,” Johannsen says. The most effective way to prevent mono is to avoid very intimate contact, such as kissing, with someone who has mono for several months, even after the person is feeling better. EBV is most easily spread through direct body-fluid contact, such as by exchanging saliva while kissing or blood or semen contact during sex, blood transfusions, or organ transplants. But EBV can still live in bodily fluids once they’re outside the body, too. So avoid sharing utensils, cups, or toothbrushes with someone you know who has been infected with EBV or mono, and steer clear when they sneeze or cough. The bottom line is that you are not likely to catch mono from someone in a nonintimate setting, such as attending class with or standing in line near someone who’s been infected with EBV. And if you take precautions, you can avoid getting EBV — that is, if you don’t already have it — even from someone in your household, says Johannsen.
