The ‘Mystery Illness’ Taking the US by Storm Is the Common Cold

What do you call it when you've got a runny nose, a fever, and a cough, but you don't have COVID-19? As TikTokers are discovering, that's not a new, mysterious illness. It's just the plain old common cold.

On TikTok, some users have noticed that they've been getting sick, sicker than they remember being in the past. These users don't have COVID and don't have strep, but they also don't know what they are suffering from.

In some cases, TikTok users have positioned this as a mysterious, new illness.

It isn't a new illness, though. These people have all described the symptoms of a common cold. Over the last year, as the majority of people have been masking indoors and avoiding social situations more broadly, rates of flu and infections that cause the common cold have plummeted. But as things have opened back up in the United States as people get vaccinated, colds are coming back in a big way. At one health network in Utah, for example, cases of RSV, one of the many viruses that causes the common cold, are up 10 times over normal rates.

So there are more colds than normal, but this isn’t some grand mystery.

"When we talk about a cold there are actually hundreds of viruses that cause colds. That’s why you keep getting them. That’s why when you have a child in preschool, they are always bringing them home and you’re catching them," Catherine Troisi, an infectious disease epidemiologist at UTHealth School of Public Health in Houston told Motherboard. 

When you watch videos on TikTok where people are describing their colds, it's easy to get the impression that more people are getting sick than before. Although more people seem to be aware of common colds, or at least are finding the experience of getting a cold novel enough to post about it, according to Troisi, it's unlikely that we're more susceptible to them now than before the pandemic. We just haven't been going outside as much.

"It is true that we have not been exposed so much to colds during the last year. Whether our immune systems faded so much during that year to these viruses, we don’t really know because we’ve never been in this situation before," Troisi said. "Theoretically it’s possible that our immunity has waned somewhat, but I wouldn’t say that’s been proven and I wouldn’t say that that’s the only explanation."

The frequency of TikToks on this topic might also have to do with the fact that people who use these platforms are younger, and a little bit more susceptible to colds.

"Generally speaking, children and young people experience more frequent colds and more severe symptoms, and TikTok users tend to be younger so the sample is biased in that respect," Elizabeth Scott, a microbiologist and Associate Dean and Professor of Biology, College of Natural, Behavioral, and Health Sciences at Simmon’s University told Motherboard. 

"The common cold is endemic in most human societies and it is not surprising that we are encountering it again as we start mingling more freely and without masks," Scott said. "I don’t see it as a concern because whilst it is a misery to experience the cold symptoms, it is not a threat to our health."

So if you're mysteriously sick this summer, try to remember about the existence of the common cold. It still sucks to get sick, but the common cold probably won't kill you.

Shayla Love contributed reporting.