XEC may sound like some sort of rock band, cryptocurrency, or male enhancement supplement. But the XEC COVID-19 variant is something you probably don’t want to see at a party or anywhere near your privates. It’s the latest COVID variant to grab attention and spread across the globe. And a big question after the so-called “Summer of COVID” is whether the XEC variant will fuel the next COVID surge in the coming months.

This past summer — yes, the summer of 2024 is now over — was nicknamed the “Summer of COVID” because it appeared to be the largest summer COVID spike since July 2022. That’s based on wastewater data from the Centers for Disease Control and Prevention, because many people have effectively stopped getting tested for COVID. Without adequate testing and reporting of test results, any number of COVID-19 cases is likely a substantial underestimate of the true number.

The summer surge was led by the so-called FLiRT variants, primarily KP.3.1.1 and KP.3. It didn’t help that the majority of people flirted with the virus by not taking precautions against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). For example, the use of face masks seems to have disappeared, as do skinny jeans, even though studies have clearly shown that N95 respirator masks can reduce the transmission of SARS-CoV-2.

This fall, we may see a decline in cases after the peak. But the emphasis here is on the word “may.” That’s because after four years of COVID, the U.S. still doesn’t have a reliable COVID surveillance system. COVID is certainly not gone. While vaccination and prior exposure have reduced the risk of more severe COVID-19 outcomes, SARS-CoV-2 can still land some people in the hospital. It also appears to still cause long COVID in some people.

And now, surprise, surprise, there’s a new prickly child on the market: the aforementioned XEC variant. The XEC is essentially the lovechild of the KS.1.1 and KP.3.3 COVID variants.

The XEC was first discovered in Berlin, Germany, in June. But what happened in Berlin didn’t stay in Berlin. This ball of no fun has already appeared in 27 different countries in Europe, North America, and Asia. That includes showing up in 12 states in the United States so far, according to Scripps Research’s “Outbreak.info” webpage. And while it’s not yet the dominant COVID variant, it does appear to have a fitness advantage over other circulating variants.

Now, a fitness advantage doesn’t mean that this variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) wears tights and can do more glute bridges. It means that for some reason it can spread faster or more easily than other variants. The reason isn’t yet clear. Perhaps those infected with this variant are able to shed more of the virus. Perhaps the XEC variant is able to get into cells more easily. Or it could be that this variant is better at evading existing immune protection from vaccination or previous infection. More data and studies are needed to determine which of the above is the case. But the fact that the XEC variant appears to spread quite quickly suggests that it does indeed have some sort of fitness advantage.

More data and studies are also needed to determine whether the XEC variant is more or less likely to cause severe COVID symptoms and outcomes than current and previous variants. Again, this will be difficult to say without more extensive testing and a more comprehensive surveillance system than what is in place now. The updated COVID vaccines now available should provide at least some protection against the XEC variant. Exactly how much remains to be seen.

There is a high probability that there will be another COVID peak in the coming months. In recent years this has happened in November. This is not surprising, because in November the weather becomes considerably colder and drier and many more activities move indoors.

But don’t assume that COVID activity won’t pick up again before November. And don’t assume that there will be a warning just before the next spike, given the lack of a more reliable and comprehensive monitoring system. So, you may want to be XEC-cautious yourself and take precautions if you don’t want to get COVID and possibly long COVID.