What Is the 'Mystery Virus' Trending on TikTok?

If you haven’t stayed home sick recently, you probably know somebody who has. During cold and flu season, most of us at some point come down with a bug that brings symptoms like nausea, fatigue, light-headedness, and congestion.

But in the wake of the COVID-19 pandemic, it can be hard not to worry when lots of these symptoms strike all at once, especially when you can’t figure out just what “mystery virus” is making you ill.

“Everyone in the United States is getting sick by some virus, but they don’t know what it’s called, they don’t know where it’s coming from, but somehow everybody is getting sick,” one TikToker says in a video with 1.7 million views.

“When I say everybody, I’m including myself too,” says the TikToker, who goes by @thatgirlkanesha. “I just had this so-called virus last week. I was feeling very very lightheaded. I felt like I had to vomit. I felt like I was going to pass out. Like all of these symptoms are really not adding up to me.”

What Could the ‘Mystery Virus’ Be?

This so-called “mystery virus” trending on TikTok doesn’t appear to be a respiratory virus like COVID-19, respiratory syncytial virus (RSV), or the flu. And some TikTokers are complaining of issues like pink eye, which don’t fit the classic symptoms for these respiratory illnesses.

While this may seem like cause for alarm, there may be a perfectly simple explanation, says William Schaffner, MD, a professor of infectious diseases at Vanderbilt University Medical Center in Nashville, Tennessee.

“There are numerous other seasonal respiratory viruses circulating during the winter months beyond the familiar serious influenza, COVID, and RSV,” Dr. Schaffner says.

Many common colds, for example, are caused by rhinoviruses, Schaffner says. These are typically mild upper respiratory infections with symptoms like a runny nose, sore throat, headache, body aches, and cough.

Adenoviruses, another ailment that usually causes mild cold symptoms, may also be behind the “mystery illness” because it can lead to pink eye, Schaffer posits.

With viral illnesses like these, “the vast majority of folks will recover after a few days,” Schaffer says.

What Can Relieve Symptoms of a Mystery Virus?

Before you assume you have a “mystery virus,” you should get tested for influenza and COVID-19 to rule out these illnesses, Schaffner advises. That’s because there are medications to help prevent severe illness such as Paxlovid for COVID-19 and Tamiflu for influenza.

“This is particularly important if you are in a high-risk group for more serious complications — if you are 65 or older, if you have one or more chronic medical conditions, or if you are immunocompromised,” Schaffner says.

Assuming you test negative, the best thing you can do is drink lots of fluids and take over-the-counter medicines to help ease symptoms.

When Should You See a Doctor?

Even though many people recover from a viral infection within a matter of days without ever seeing a doctor, there are times when medical attention is necessary.

“If your fever is high or persists or you have shortness of breath or other worrisome symptoms, contact your healthcare provider,” says Peter Hotez, MD, PhD, a professor of pediatrics and molecular virology and microbiology at Baylor College of Medicine and co-director of the Texas Children’s Hospital Center for Vaccine Development in Houston.

“You may have secondary bacterial pneumonia or other serious bacterial infection and require an antibiotic,” Dr. Hotez says.

What Should You Do to Protect Others From Whatever Virus You Have?

Whether you have a “mystery virus” or a respiratory illness like COVID-19, the flu, or RSV, you should stay home and steer clear of others as much as possible until your symptoms start improving and you’ve been fever-free for at least 24 hours without taking fever-lowering medications, Schaffner says. You should also wash your hands often.

These are among the new guidelines from the Centers for Disease Control and Prevention (CDC) for reducing the spread of respiratory illnesses. Once you go out in public, the CDC also recommends wearing a mask for five days to minimize the risk of infecting others.

“All these viruses are quite contagious,” Hotez says. “The N95 and KN95 masks that work for COVID usually work for these other viruses.”