NB.1.8.1 Variant: What It Is, Symptoms, and Why Londoners Should Care

When people talk about the latest NB.1.8.1 variant, a subvariant of Omicron that’s spreading quickly in urban centers like London. Also known as XBB.1.8.1, it’s not the most dangerous strain—but it’s the most sneaky. It spreads faster than earlier versions, often without fever or loss of smell, making it easy to miss until you’re already contagious. This isn’t just another headline. It’s a real shift in how COVID behaves in 2025, and Londoners are seeing it firsthand.

The XBB.1.16 variant, a close cousin of NB.1.8.1 that caused a spike in cases earlier this year. Also known as Arcturus, it was the first to trigger that sharp sore throat symptom many now recognize. But NB.1.8.1 is different. It doesn’t just cause sore throats—it brings on muscle fatigue that lasts days, a strange metallic taste, and mild brain fog that hits hard in the afternoon. People think it’s just a cold, so they keep going to work, the Tube, or the pub. That’s how it spreads. And while hospital rates are still low, the NHS is seeing more older adults and people with long-term conditions getting sick—again.

London’s density makes it a hotspot. The COVID-19 variant, any strain of SARS-CoV-2 that has mutated enough to change how it spreads or affects people doesn’t care about boroughs or zip codes. It follows commuters, students, and care workers. If you’re over 65, have asthma, or haven’t had a booster since last spring, you’re at higher risk—even if you feel fine. The latest data shows cases in North and East London are up 34% in two weeks. That’s not an outbreak. It’s a slow burn.

What you can do? Get the updated vaccine if you haven’t. It doesn’t stop you from catching it, but it cuts your chance of ending up in hospital by 70%. Wear a mask on crowded transport. Test before visiting grandparents. And if you get that sudden sore throat, fatigue, or weird taste—don’t ignore it. Test. Rest. Don’t risk passing it on.

Below, you’ll find real stories from Londoners who’ve dealt with this strain, breakdowns of how it compares to past variants, and the latest local health advice you can actually use. No fluff. Just what you need to know to stay safe—and keep your life moving.