It’s cold and flu season, so coming down with a respiratory illness isn’t exactly uncommon. 

However, TikTok is sparking rumors — and likely medical misinformation — about a so-called new “mystery virus” that hasn’t been identified.

The videos discussing the virus began circulating in February, when one video posted by @thatgirlkanesha went viral — sparking others to chime in and claim they were experiencing the same symptoms.

“You mean to tell me that everyone in the U.S. is getting sick by some virus but they don’t know where it’s called?” she said in the video. “When I say everybody I’m including myself too. I just had this so-called virus last week. I was feeling very lightheaded, I felt like I had to vomit, I felt like I was going to pass out. All of these symptoms are not adding up to me.”

Viral claims snowball

The video blew up online — gaining more than 1.6 million likes and over 53,000 comments. 

“Tested negative for everything but so sick,” one commenter commiserated. “Is anybody’s nose and throat hurting for days?” another commenter asked. “I was coughing so bad I could not sleep at night,” another added.

Within the following days, more and more people posted videos saying they’ve had the same symptoms. One TikToker, @laksmysanchez, received more than 83,000 likes on her video about the same illness.

“Can somebody explain to me how come we’re all sick with the same exact thing, but it’s not flu, it’s not a cold, it’s not COVID?” she said. “But we all have the same symptoms. We can’t breathe, massive sore throat. Some people are even getting pink eye as well.”

@laksmysanchez

I cannot be the only one who’s questioning this. I see so many people on my for you page complaining about the same symptoms and people around me as well. The insane spread of pink eye that’s going around is also very concerning.. what’s happening? #newvirus#newvirusgoingaround#newcovidstrain#weirdflu#flu

♬ original sound – 𝙻𝙰𝙺𝚂𝙼𝚈 𝙰 𝚂𝙰𝙽𝙲𝙷𝙴𝚉
@so_angie7

Replying to @Vanessa Nichole sending a prayer up. This virus has got everyone in a chokehold. #flu #cold #sick #covid #foryoupage

♬ original sound – so_angie
@_ajtsanchez

Anyone else experiencing similar symptoms? I just thought it was a cold…

♬ original sound – AJ

The “mystery virus” on TikTok has echoed some of the hysteria and confusion around COVID-19’s emergence four years ago, with some videos even alluding to another pandemic emerging.

@tgypt0

thus “unknown virus” is giving a pandemic vibe #relatable

♬ Let Go – Ark Patrol

HCPs combat misinformation

The fear-mongering videos have led several experts to respond to the widespread rumors. 

Dr. Zachary Rubin, a pediatric allergist and clinical immunologist who holds a large following on TikTok, posted a reaction video explaining that one possibility is that the “mystery virus” could simply be COVID-19.

“It’s probably not much of a mystery, because… COVID-19 is still circulating at high levels throughout the U.S.,” he explained, pointing out that wastewater samples were still showing high levels of COVID as the virus has become more endemic in nature.

“A lot of people aren’t testing for [COVID], but even if you test for it with a home test, it doesn’t necessarily pick it up right away and ideally you need to have multiple negative tests in order to ensure you actually do not have COVID,” Rubin continued. “Or, you get a PCR test that is done in a doctor’s office because that’s much more sensitive at picking up the virus from your nose.”

@rubin_allergy

@n e s h a 🌸 What is this mystery virus going around? It is probably COVID-19. Many people are either not testing for it or they had a home test and had a false negative result and did not redo the test 48 hours later. The updated vaccine may help reduce your chances of infection and/or severe illness. General educational purposes only. #covid19 #viral #mystery #tiktokdoc #learnontiktok @AJ @Heyimstin

♬ Mysterious and sad BGM(1120058) – S and N

Non-COVID options

If it’s not COVID, it could also simply be a number of other respiratory viruses that aren’t unheard of. 

In another reaction video, Rubin pointed out that there are plenty of respiratory pathogens circulating outside of RSV, influenza and COVID-19 that people could test for when they experience an acute illness.

A more extensive panel test could pick up any number of other viruses, including different influenza subtypes, human parainfluenza virus (HPIV), human bocavirus, whooping cough, enterovirus and coronavirus 229E.

Other public health experts and healthcare professionals agreed that the so-called “mystery virus” was probably some type of cold or flu strain. However, they also expressed concerns about how easily misinformation is spread on the platform.

Health misinformation on TikTok has been a major issue since the platform gained popularity, with one study finding that 84% of mental health content there was misleading.

In mid-February, the Centers for Disease Control and Prevention (CDC) posted an update about the 2023-2024 respiratory virus season, noting it was likely past its peak — but “far from over.”

General illnesses were declining after a late December uptick, the CDC stated, with COVID-19, flu and RSV hospitalizations dropping as well through January.

“However, respiratory disease activity remains elevated, and some flu activity indicators have increased again,” the CDC noted. “While the respiratory virus season is likely past its peak, it is definitely not over. There is still a lot of respiratory virus activity, so it’s not time to let our guard down.”

The CDC emphasized getting vaccinated as one way to prevent severe illness — as well as taking protective steps like testing, masking, washing hands and physical distancing when you are experiencing symptoms.