Virological characteristics of the SARS-CoV-2 XEC variant

Welcome to the Heliox Podcast! Today, we're diving into the latest developments in COVID-19 research. Leading scientists have recently published fascinating findings about a new variant called XEC, which is showing some remarkable characteristics. As we continuously work to understand this evolving virus, we'll break down what the latest research tells us about its behavior and what it might mean for our communities. Whether you're a science enthusiast or just wanting to stay informed, we've got you covered with clear, accessible insights into this important discovery.

Virological characteristics of the SARS-CoV-2 XEC variant

Yu Kaku, Kaho Okumura, Shusuke Kawakubo, Keiya Uriu, Luo Chen, Yusuke Kosugi, Yoshifumi Uwamino, MST Monira Begum, Sharee Leong, Terumasa Ikeda, Kenji Sadamasu, Hiroyuki Asakura, Mami Nagashima, Kazuhisa Yoshimura, The Genotype to Phenotype Japan (G2P-Japan) Consortium, Jumpei Ito, Kei Sato
doi: https://doi.org/10.1101/2024.10.16.618773
https://www.biorxiv.org/content/10.1101/2024.10.16.618773v1
https://www.biorxiv.org/content/10.1101/2024.10.16.618773v1.full.pdf


UPDATED: #Canada #SARSCoV2 variants.

Of 310 samples from 10/6 - 10/12:

XEC.*: 12.9% (⬆️ 8.4%/1069)
LB.1.*: <2% (⬇️ 3.4%)
KP.1.1.3.* (incl. LP.1): 3.6% (⬆️ 4.3%)
KP.2.3.*: 3.6% (⬆️ 3%)
KP.3.1.1.* (incl. MC.1): 71% (⬆️ 66.3%)
MC.1: 4.8% (⬆️ 4.4%)

anarchodelphis.tumblr.com/CanadaVariants #COVID19

https://x.com/anarchodelphis/status/1848177921174966321?s=61&t=12lLWpJUelqJtwbaGIqX4Q

Tracking #SARSCoV2 #Lineages - Globally |10/19/24

Top lineages -#30DayTrends #G30

KP.3.1.1  (41.9%)
XEC  (10.5%)👀
KP.2.3  (3.1%)
MC.13   (3.1%)
MC.16   (2.6%)
MC.1  (2.5%)
KP.3.3  (2.3%)
LB.1.3.1  (1.9%)
MC.10  (1.7%)
MC.11  (1.4%)
XEC.2  (1.3%)👀

https://public.tableau.com/app/profile/raj.rajnarayanan/viz/ConvergentLineages-VariantSoup-World/G20

Transcript

0:00

Welcome back, Deep Divers. You know we love a good mystery here on the Deep Dive, and you've sent us a real head scratcher this time. A scientific paper on the rise of this new XCC SARS-CoV-2 variant. And let me tell you, it's got all the makings of a viral thriller. Intrigue, a touch of genetics and implications for, well, everyone. It's a fascinating look at how these viruses evolve and adapt almost like they're reading from a playbook we haven't quite deciphered yet. Okay. So before we get into the nitty gritty of XCC, let's rewind a bit. Okay. The paper starts by talking about a JN1 variant. You might remember it as BA28611, which took over from those XBB lineages we were tracking earlier this year. Remember those? Right, JN1. It's like the virus family tree keeps branching out in unexpected ways. Yeah. And JN1 decided to throw a family reunion of its own spawning subvariants, like Kp.2 and Kp.3. Now, each of these subvariants brought its own little quirks to the table, slight mutations in their genetic makeup. Quirks that can sometimes change the entire game, right? Exactly. these tiny tweaks can mean a subvariant spreads faster, gets better at dodging our immune defenses, or even just hangs around longer. Sneaky little things. And that brings us to the current reigning champ, at least as of October 2024, Kp.3.1.1. This is the one making headlines globally as the most prevalent variant. But of course, in the world of viruses, being on top is a temporary gig. There's always a new contender waiting in the wings. Which leads us to our main event, XCC. Now this variant has a particularly intriguing origin story. It's what's called a recombinant variant, which sounds a bit like something out of a science fiction movie, right? It's certainly a testament to the adaptability of viruses. Imagine two different variants in this case, Ks.1.1 and Kp.3.3 infecting the same cell at the same time. Okay, a little viral meat cute. Exactly. And during this encounter, they swap bits of their genetic material like trading baseball cards, and voila, you have a brand new variant, in this case, XCC. And it's not just some random mishmash. Right. The paper highlights some specific mutations that XCC picked up from its parents, ST22N and SF59S. Now, I know those names might sound like a radio code, but the important thing to remember is these mutations happened because of this recombination event between very specific locations in their genetic blueprints. It's like changing a few lines of code in a complex program. Those alterations can have a ripple effect on the entire system. And in this case, these changes are what have scientists particularly intrigued, even a bit concerned about XCC. Because it's not just about where it came from, right? It's about what these mutations allow XCC to do. And that's what we're going to unpack next, how easily it spreads, how good it is at getting into ourselves, and whether it can evade the defenses our bodies have built up. It's a bit of a biological chess match. And right now, XCC seems to be making some very strategic moves. All right. Well, there you have it. We've set the stage, introduced the players, and now we're ready to dive into the real drama. Stay with us, Deep Divers, because things are about to get interesting. So we've talked about XCC's origin story, but let's get to the heart of the matter. How does this variant actually behave out in the wild? Well, one of the key metrics scientists look at is the effective reproduction number or RE for short. It's essentially a measure of how easily a virus spreads. Okay, so like if one person with a cold infects two other people, on average, the RE would be two, right? Exactly. And the higher the RE, the faster the virus is likely to spread through a population. Now, what has researchers' concern is that studies from several countries, the US., UK., France, Canada, and Germany, suggest that XCC might have a higher RE than even KP111. So it's not just some theoretical advantage. This thing seems to be outpacing other variants in the real world. That's what the data suggests. And it's why scientists are paying such close attention to XCC's movements. But it's not just about how fast it spreads. The study also delved into XCC's ability to infect cells, which is a critical part of its success story, so to speak. So it's like getting into the club is one thing, but then you've got to work the room, right? Make those cells produce more virus particles. Precisely. Now, to study this safely, scientists use these ingenious tools called pseudoviruses. They're basically harmless stand-ins that mimic certain aspects of the real virus. Of course, they'll extent doubles for the dangerous stuff. Exactly. And in this case, these pseudoviruses allowed researchers to test how well XCC infected cells compared to its predecessors. And what they found is that XCC, along with Kp.3.1.1, was significantly more infectious than Kp.3. Okay. So XCC is better at getting into our cells, but what about our body's security system, our immune system? Can XCC get past those defenses too? That's where things get even more interesting. Remember those key mutations we talked about, ST22N and SF59S? Well, one of them, SF59S seems to be a real game changer when it comes to infectivity. So that's like XCC's secret weapon. You could say that it seems to give XCC an edge in binding to our cells, making it more efficient at getting in and causing infection. Imagine a locking key Kp.3 might fumble around a bit, but XCC seems to have found the perfect key to unlock those cell doors. That's a little unnerving, but also kind of brilliant from the virus' perspective, right? It highlights the constant evolutionary arms race between viruses and our immune systems. But the plot thickens when we look at XCC's ability to evade those immune defenses. Okay. So is XCC wearing an invisibility cloak? How is it dodging our immune system? Think of it more like a disguise. The researchers tested XCC against antibodies from the blood of people who had been previously infected with different variants. these antibodies are like our body's memory of past encounters with the virus ready to fight back if they see it again. Like our immune system's most wanted posters. Exactly. But what they found is that XCC was significantly better at evading these antibodies, especially those from people who had been infected with the Kp.3.3 variant. So if you had Kp.3.3, your immune system might not recognize XCC as easily. That's a bit worrying. It does raise concerns about the effectiveness of our existing immunity against this new variant. It's like XCC has studied the playbook and learned how to dodge some of our best defenses. All right. So we've got a variant that spreads more efficiently, infects cells more effectively. A and D can evade some of our immune responses. Not exactly the news we were hoping for. It's definitely a cause for concern and highlights the need for continued vigilance. But remember, this is an ongoing story. Scientists are working tirelessly to understand XCC's full capabilities and what we can do to counter its moves. Speaking of which, what do these findings actually mean for us? What are the real world implications of a variant like XCC emerging? So we've uncovered some pretty concerning things about XCC. It spreads quickly, it's good at getting into our cells, and it can even evade some of our immune defenses. What does this mean for us in the grand scheme of things? Well, the million-dollar question is, will our current vaccines hold up against this new variant? Right, because vaccines are designed to teach our immune systems to recognize and fight off the virus. But if XCC is wearing a disguise... Exactly. That's what scientists are racing to figure out. Right now, they're conducting what are called neutralization assays, which basically test how well antibodies from vaccinated individuals can block XCC from infecting cells. So kind of like putting those antibodies to the test in a controlled lab setting. Precisely. these tests will tell us if our existing vaccines offer sufficient protection against XCC, or if we need to consider updating them. And it's not just about vaccines understanding how XCC evades our immune system, could also be crucial for developing new treatments. Because if we know how XCC is hiding, we can develop better ways to target it. Exactly. It's all connected. This research is like a flashlight in a dark room, illuminating critical aspects of this new variant and guiding our response. That's actually a great way to put it. It's easy to feel overwhelmed by all this information about new variants, but it's important to remember that scientists are on the case, and knowledge is our most powerful tool. Absolutely. What I find particularly fascinating about this study is how it highlights the dynamic interplay between virus evolution and our immune response. It's a constant back and forth each side trying to outmaneuver the other. Like a high stakes game of chess played out at the microscopic level, and we're all just trying to stay a few moves ahead. So to bring it back to our listener, what should we be doing with all this information? Well, first and foremost, don't panic awareness is key. Stay informed about the latest developments, follow public health recommendations, and get vaccinated and boosted if you haven't already. Solid advice, and remember, this is an ongoing story. Science is a process, not a destination. researchers are learning more about XCC every day, and we'll continue to share those insights with you as they emerge. Exactly, and that's the beauty of science. It's always evolving, always pushing the boundaries of our understanding. On that note, here's something for you to ponder. This study focused on specific mutations in XCC. But what other evolutionary tricks might these viruses have up their sleeves? How might our immune systems learn to adapt and fight back in this on-going arms race? It's a fascinating question to consider, and one that scientists will undoubtedly be exploring for years to come. Until next time, stay curious, Deep Divers.