What COVID variant is out now in the UK? Latest strain as of December 2025
As of December 2025, the dominant COVID-19 variant circulating in the UK is XFG.3, a subvariant of the XFG lineage, commonly called Stratus in media reports. It’s not the scary new threat some fear - it’s just the latest in a long line of Omicron descendants, evolving quietly, spreading easily, and mostly causing mild illness. But if you’re wondering what’s going around right now, especially with winter heating up and holiday gatherings planned, you need to know what you’re up against.
What’s actually circulating in the UK right now?
The UK Health Security Agency (UKHSA) tracks every positive test that gets sequenced. Their latest data, from early December 2025, shows XFG.3 makes up 43% of all cases. That’s up from 41% just two weeks ago. The original XFG strain is down to 22%, and two other subvariants - XFG.5 and XFG.3.4.1 - together account for about 10%. That means nearly 75% of all detected cases are some form of XFG.
The other main player is NB.1.8.1, nicknamed Nimbus. It’s still around, but its numbers are falling. It’s now responsible for only 7% of cases, down from 11% in September. It’s not gone, but it’s being pushed out by XFG.3.
Why does this matter? Because XFG.3 is better at slipping past immunity. It doesn’t cause worse illness - hospitalization rates haven’t spiked. But it’s better at infecting people who’ve had past infections or vaccines, especially if they haven’t had a recent booster.
What are the symptoms?
If you catch XFG.3, you’re likely to get symptoms that feel like a bad cold. The most common ones, based on NHS data from September through November 2025, are:
- Sore throat (68%)
- Runny nose (62%)
- Fatigue (57%)
- Hoarse voice (41%)
- Cough (53%)
The hoarse voice is the one people keep talking about. It’s not new to science - other variants have caused it too - but it’s showing up more often with XFG.3. Reddit threads from London, Manchester, and Glasgow are full of people saying, “I didn’t feel sick, but I lost my voice for three days.” One user from Leeds wrote: “Thought I was just yelling at the kids. Tested positive. Turns out it’s Stratus.”
Most people recover in 5 to 7 days. But about one in three report lingering fatigue or a cough for up to two weeks. That’s not unusual. Even with earlier variants, some people just took longer to bounce back.
Are vaccines still working?
Yes. The current booster, rolled out in October 2025, targets the XBB.1.5 and BQ.1.1 strains - not XFG.3 directly. But it still works. UKHSA data shows the booster is 68% effective at preventing symptomatic infection and 92% effective at keeping you out of the hospital.
That’s why the focus isn’t on stopping every case - it’s on preventing serious illness. People over 50, those with weakened immune systems, and healthcare workers are the ones encouraged to get the updated shot. Nearly 15 million people in the UK have already received it. If you’re healthy and under 50, your last dose - even if it was a year ago - still gives you strong protection against severe outcomes.
There’s no new vaccine for XFG.3 yet. But officials are already preparing one. The Joint Committee on Vaccination and Immunisation (JCVI) confirmed in late September that a new booster targeting XFG lineages will be available by mid-November 2025. It’s not mandatory. It’s not even widely advertised. But if you’re high-risk or just want extra peace of mind, it’s there.
Should you still wear a mask?
The UKHSA hasn’t changed its advice. No mandates. No lockdowns. No mask rules. But they still recommend masks in crowded indoor places - especially if you’re around older people, pregnant individuals, or anyone with health conditions.
Think about it this way: you wouldn’t go into a packed train with a bad cold. Why treat COVID any differently? If you feel even a little off, wear a mask. If you’re around someone who’s vulnerable, wear one. It’s not about fear. It’s about common sense.
Good ventilation helps too. Open windows. Use air purifiers if you have them. Handwashing still matters - not because the virus lives on surfaces for days, but because people touch their faces constantly.
What about testing?
You can still get a free PCR test if you’re symptomatic and want to know for sure. But most people don’t bother anymore. Rapid antigen tests are available over the counter at pharmacies. They work fine for detecting XFG.3 - they just don’t tell you which variant you have. That requires sequencing, which only happens in a small fraction of cases.
Some people are frustrated they can’t get variant-specific results. But here’s the truth: it doesn’t change your treatment. Whether it’s XFG.3 or Nimbus, you rest, hydrate, and isolate if you’re contagious. The health system isn’t tracking variants to change your care - it’s tracking them to watch for surprises.
Is this the end of the line?
Probably not. Experts at the London School of Hygiene & Tropical Medicine say SARS-CoV-2 is on a 120-day cycle. Every four months, a new variant takes over. XFG.3 is likely to be replaced by something else by February or March 2026.
That doesn’t mean the next one will be worse. It just means the virus keeps changing. It’s not a race to the finish - it’s a slow, steady evolution. The goal now isn’t to eliminate it. It’s to manage it like the flu or the common cold.
And that’s exactly what the UK is doing. No panic. No restrictions. Just monitoring, vaccination for those who need it, and advice for everyone else: stay home if you’re sick, mask up around vulnerable people, and get the booster if you’re eligible.
What should you do right now?
Here’s the simple, no-nonsense checklist:
- If you’re over 50, immunocompromised, or pregnant - get the updated booster if you haven’t already.
- If you have symptoms, test with a rapid kit. Don’t wait for a PCR.
- If you test positive, stay home for at least 5 days. Avoid vulnerable people for 10.
- If you’re going to a crowded event - like a family dinner or a holiday party - wear a mask, especially if you’re unsure of others’ vaccination status.
- Don’t stress about the variant name. Focus on protection, not labels.
There’s no need to cancel plans. No need to fear going out. The UK has moved past the crisis phase. XFG.3 is just another cold virus with a fancy name. You’ve already survived dozens of variants. You can handle this one too.
What is the most common COVID variant in the UK right now?
As of December 2025, the most common variant in the UK is XFG.3, a subvariant of the XFG lineage (also called Stratus). It accounts for over 40% of sequenced cases and is spreading faster than other current strains like NB.1.8.1 (Nimbus).
Is the XFG variant more dangerous than previous ones?
No. There’s no evidence that XFG.3 causes more severe illness than earlier Omicron variants. Hospitalization rates remain low, and the virus is not showing signs of increased virulence. Its main advantage is better immune evasion, not stronger disease.
Do current vaccines work against XFG.3?
Yes. The updated booster, designed for XBB.1.5 and BQ.1.1, still offers 68% protection against symptomatic infection and 92% protection against hospitalization from XFG.3. It’s not perfect, but it’s enough to prevent serious outcomes.
Should I get the new XFG-targeted booster?
If you’re over 50, immunocompromised, or in regular contact with high-risk individuals, yes. The new booster targeting XFG lineages became available in November 2025. For healthy younger adults, the previous booster is still sufficient for protection against severe disease.
Why is hoarse voice linked to the Stratus variant?
Hoarse voice is a symptom that’s become more common with XFG.3, though not unique to it. UKHSA and NHS data show about 41% of confirmed XFG.3 cases report this symptom. It’s likely due to how the variant interacts with throat and vocal cord tissues. It’s not dangerous, but it can be disruptive - and it’s one reason people are noticing this variant more.
How long should I isolate if I test positive?
The UKHSA recommends isolating for at least 5 days from when symptoms start or from the positive test date. Avoid close contact with vulnerable people for 10 days, as you may still be contagious. Return to normal activities only when you feel well and your fever is gone for 24 hours without medication.
Are rapid tests still reliable for detecting XFG.3?
Yes. Rapid antigen tests detect the presence of the virus, not the specific variant. They remain reliable for identifying active infection with XFG.3. They won’t tell you it’s XFG.3 - only that you’re infected. PCR sequencing is needed to identify the variant, but that’s not necessary for personal care decisions.
About Author
