As the United Kingdom heads into the chill of autumn 2025, a familiar specter is once again making headlines: Covid-19. But this time, it’s not just the return of the virus that’s causing concern—it’s the emergence of two new variants, Stratus (XFG and XFG.3) and Nimbus (NB.1.8.1), that are fueling a notable surge in cases across the country. According to the World Health Organization (WHO) and the UK Health Security Agency (UKHSA), these strains have swiftly become the most prevalent forms of Covid in the UK, prompting renewed calls for vigilance and public health action.
Stratus, first identified in January 2025, now accounts for an estimated 63% of monitored Covid cases in the UK, while Nimbus, detected around the same time, makes up about 25%, according to both WHO and UKHSA data reported by The Mirror and Daily Mail. The rapid spread of these variants has been matched by a doubling of infection rates since August, with positivity rates climbing from 7.6% to 8.4% in just one week, and hospital admissions rising from 2.0 to 2.73 per 100,000 people, as noted by the UKHSA.
So, what sets these new variants apart? Dr. Sara, speaking on ITV’s This Morning on October 3, 2025, highlighted two telltale symptoms: “mainly a hoarse voice and a kind of razor blade type of sharp sore throat.” These symptoms, she explained, can also be accompanied by headaches, coughing, a runny or blocked nose, and in the case of Nimbus, digestive issues such as nausea, diarrhoea, bloating, and stomach pain. “Cases are rising,” Dr. Sara warned, “as with many other respiratory illnesses during this time of year.”
Despite these distinctive signs, distinguishing Covid from the flu or a common cold remains tricky, as the overlapping symptoms can easily cause confusion. The NHS continues to list a familiar array of Covid symptoms: high temperature or chills, a new continuous cough, loss or change of smell or taste, shortness of breath, fatigue, aching body, headache, sore throat, runny or blocked nose, loss of appetite, diarrhoea, and feeling sick or vomiting. Most people, the NHS says, recover within a few weeks, but for some, symptoms may linger or become more severe.
Professor Lawrence Young, a virologist at Warwick University, told the Daily Mail that the early autumn surge is “worrying so early in the Autumn period.” He attributed the rise in cases to several familiar factors: children returning to school, colder temperatures driving people indoors—often into poorly ventilated spaces—and waning immunity in the population. “The symptoms are mainly similar to previous Covid infections—headache, coughing, runny nose,” Professor Young explained. “But infection with the new variants is associated with a hoarse voice or a ‘razor blade’ sore throat.” Stratus, he added, has also been linked to persistent dry coughs, tiredness, and fever.
Even as the genetic tweaks in these variants may make them more transmissible, the good news is that, so far, neither Stratus nor Nimbus appears to cause more severe illness than earlier strains. “Based on the available information so far, there is no evidence to suggest that the variants cause more severe disease or that the vaccines in current use will be less effective against them,” confirmed Dr. Alex Allen, a consultant epidemiologist at UKHSA, as reported by LADbible. The WHO echoed this reassurance, stating: “It’s normal for viruses to mutate and change, and as more data becomes available on these variants we’ll have a better understanding of how they interact with our immune systems and how to optimise our protection, as well as actions we can take to keep the most vulnerable safe and live our lives as normally as possible.”
Nevertheless, public health experts are not taking any chances. On October 2, 2025, the UK launched its winter vaccination drive, urging millions—especially those over 75, people with weakened immune systems, care home residents, pregnant women, and children—to come forward for Covid and flu jabs. The campaign is a reminder that, while mandatory isolation and mask requirements have been lifted, voluntary guidance remains in place. The UKHSA advises anyone with symptoms to stay at home if possible, avoid contact with vulnerable individuals, and wear a face covering if they must go out.
Professor Stephen Griffin, a virology expert at the University of Leeds, has been especially vocal about the need for continued caution. “Anybody, regardless of how healthy they are, can develop serious symptoms. It doesn’t always mean that because you were fine last time, you’ll be fine this time. Things change. Our immunity changes. The virus changes,” he told the Daily Mail. Professor Griffin, who personally developed long Covid, advocates for wearing high-quality masks—FFP2 or FFP3—in crowded or poorly ventilated settings, such as buses or lecture halls. “I would wear a filtering FFP2 mask or FFP3 mask, if I was in an environment that was poorly ventilated and very busy, on a train for example, or a bus, or a crowded lecture theatre,” he said.
Long Covid, a condition linked to more than 200 lingering symptoms ranging from brain fog to heart inflammation, remains a significant concern. “We have this issue around presenteeism in this country, and it doesn’t help that, you know, things like school attendance. I think it’s really misguided that kids who are still ill are basically being encouraged to go to school. If you can isolate and you can stay home and stop it spreading to other people, then it’s definitely worth doing that,” Professor Griffin warned.
Despite the voluntary nature of current guidelines, the message from health authorities is clear: personal responsibility is key. “There are no specific rules other than people taking responsibility to ensure that the elderly and most clinically vulnerable are protected,” Professor Young explained. “You should test to check that you are infected with the Covid virus and isolate until you are not infectious.” While Covid tests are no longer free on the NHS, they are still available for purchase at pharmacies.
The government, for its part, has ruled out the return of lockdowns unless a truly severe variant emerges. Instead, the focus is on sensible precautions: vaccination, mask-wearing in high-risk situations, good ventilation, and staying home when symptomatic. As the UKHSA put it, “The most important thing is for those eligible to get their vaccination when it is due.”
With winter on the doorstep and cases climbing, the UK faces a familiar challenge—balancing a return to normal life with the ongoing reality of a mutating virus. For now, the best defense remains a mix of vaccination, vigilance, and a healthy dose of common sense.
