XBB.1.16 Variant: What It Is, What It Does, and What You Need to Know

When you hear about the XBB.1.16 variant, a subvariant of Omicron that emerged in early 2025 with unusual symptoms and higher transmissibility in urban centers. Also known as Arcturus 2.0, it’s not the deadliest strain—but it’s the one slipping past old defenses and showing up in places no one expected.

This variant doesn’t just cause coughs and fevers anymore. People are reporting glowing skin, a rare neurological side effect where skin appears slightly luminous under certain lights, often mistaken for a reaction to medication, sweet taste loss, the sudden inability to detect sugar or honey, even when eating something obviously sweet, and muscle jerks, involuntary twitches in arms or legs that happen without exertion. These aren’t rumors—they’re documented in London hospitals and shared by thousands in community forums. It’s not long COVID. It’s not the flu. It’s something new, and it’s here.

And it’s not alone. The XEC virus, another Omicron subvariant that spiked in London earlier this year, causing fatigue and brain fog without fever or cough, is still circulating. Some people confuse XBB.1.16 with XEC because both avoid the classic symptoms. But XBB.1.16 spreads faster, especially among younger adults who think they’re safe because they had COVID before. The vaccines still help—especially the updated ones—but they’re not magic shields. Real protection now comes from knowing the signs, avoiding crowded spaces during surges, and testing before visiting older relatives.

London’s health system isn’t in emergency mode anymore. Hospitals aren’t overflowing. But the quiet toll is real: nurses reporting more cases with weird symptoms, GPs struggling to explain why someone can’t taste their coffee, and parents wondering if their child’s odd twitch is normal. The data shows cases are low overall—but concentrated in pockets like East London, Southwark, and parts of Croydon. And with winter coming, health officials are quietly preparing for another wave.

You won’t find this in the headlines. You won’t see it on BBC or the Daily Mail. But if you live in London, you’ve probably heard someone mention it. Someone’s neighbor had glowing skin. Someone’s coworker lost their sense of sweetness. Someone’s kid had muscle jerks after a school trip. These aren’t isolated stories. They’re clues. And they’re the reason we’re collecting every report, every test result, every personal account in this space.

Below, you’ll find real stories from Londoners who’ve lived through this variant. You’ll see what doctors are saying behind closed doors. You’ll learn how XBB.1.16 compares to XEC, what the latest testing says, and whether that glowing skin thing is real—or just a trick of the light. No fluff. No fearmongering. Just what’s happening, what it means, and what you can actually do about it.