As autumn settles in across the United Kingdom, a new wave of Covid-19 cases is capturing the attention of health officials and the public alike. The culprit? A variant called 'Stratus', officially known as XFG and XFG.3, which has quickly become the most prevalent strain in the country. According to the UK Health Security Agency (UKHSA), Stratus now accounts for roughly 63% of monitored Covid cases in the UK, while another new variant, Nimbus (NB.1.8.1), makes up about 25%.
Discovered first in Southeast Asia in January 2025, Stratus spread rapidly, reaching 38 countries by June. By autumn, it had firmly established itself in the UK, with the latest data showing a 14.3% rise in Covid cases from September 10 to September 17, bringing the total to 1,995 cases. Hospital admissions followed suit, climbing 15.6% in August compared to the previous month, with 1,162 people admitted. The World Health Organization (WHO) has designated Stratus as a "variant under monitoring," meaning its global risk remains low, but scientists are watching closely for any changes.
What sets Stratus apart from previous Covid variants? According to BBC and other outlets, the most distinctive symptom is a hoarse or croaky voice. While Covid has always been known for a range of symptoms—headache, cough, blocked nose, exhaustion—Stratus’s hallmark is a vocal change that is catching doctors’ attention. Some patients describe it as a "scratchy or raspy voice," and others liken their sore throat to "razor blades," a term also used with the Nimbus variant. Despite these unique symptoms, most cases remain mild or moderate, and the usual advice still applies: stay home if you’re unwell, look after yourself, and avoid contact with vulnerable people if possible.
Dr. Alex Allen, Consultant Epidemiologist at UKHSA, emphasized the reassuring data: "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." The UKHSA, echoed by the WHO, maintains that current Covid vaccines are expected to remain effective against both symptomatic and severe disease caused by Stratus. While there is some evidence of slight "immune evasion"—meaning Stratus might dodge antibodies from previous infections or vaccinations a bit better than older variants—this effect is only marginal. The WHO clarified, "XFG exhibits only marginal additional immune evasion over LP.8.1. While there are reported increases in cases and hospitalisations in some of the SEAR countries, which has the highest proportion of XFG, there are no reports to suggest that the associated disease severity is higher as compared to other circulating variants."
For many, the rise in cases and hospitalizations brings back uneasy memories of previous Covid surges. In the week ending September 17, there were 78 Covid-related deaths in the UK, a slight decrease from the previous week but up 36.2% from the week before that. Among the 54 confirmed Stratus cases as of September 18, 48 were in England, with 30 linked to a care home outbreak in the East of England. Of those, 10 were hospitalized, two were tested in emergency departments, and six had unknown statuses. Importantly, no deaths were reported among these confirmed Stratus cases at the time of the latest data.
As with every new variant, the question arises: should people be worried? Health experts urge caution but not panic. According to ITV News, "it's normal for viruses to mutate and change," and while Stratus is spreading rapidly, there’s no indication it causes more severe illness or poses a greater risk than earlier Omicron descendants. The UKHSA continues to monitor the situation and encourages people to follow standard precautions—wash hands regularly, use tissues, and wear face coverings if symptomatic and needing to go out. Reinfections are possible, but they are usually mild. The agency also reminds the public that Covid tests are no longer widely free but can be purchased at pharmacies and supermarkets.
Vaccination remains the cornerstone of protection. The NHS offers free Covid vaccines to people over 75, those with weakened immune systems, and residents of care homes for older adults. The UKHSA is urging eligible groups to book their autumn jabs for both Covid and flu ahead of winter, emphasizing, "The most important thing is for those eligible to get their vaccination when it is due." Pharmacies and private clinics also provide vaccines for a fee, with prices varying but sometimes reaching £99 for a single dose. The agency’s message is clear: even as the virus evolves, vaccines continue to offer robust defense against severe illness.
What about the other new variant, Nimbus? Detected around the same time as Stratus, Nimbus has shown itself to be particularly adept at infecting new hosts. Scientists note that Nimbus is “particularly viral and easy to transmit from human to human,” thanks to its ability to stick to and enter cells more efficiently. Both Nimbus and Stratus can cause a sore throat severe enough to change the sound of the voice, but Stratus’s hoarse voice symptom is more distinctive and has become something of a calling card for the variant.
Looking at the bigger picture, the current rise in cases isn’t entirely unexpected. Respiratory viruses often surge as the weather cools and people spend more time indoors. However, the scale of monitoring is not what it was during the height of the pandemic, so reported case numbers are much lower than they would have been with widespread testing. Most of the data now comes from hospitals, which means it’s skewed toward more severe cases.
For those feeling under the weather this autumn, the advice is practical and familiar: rest, stay hydrated, and avoid spreading illness to others, especially those at higher risk. The NHS suggests simple remedies for sore throats, such as drinking fluids and even a teaspoon of honey. And, as always, keeping up to date with vaccinations is the best way to protect oneself and the community.
While Stratus and Nimbus have added new wrinkles to the ongoing Covid saga, the overall message from health officials is one of vigilance, not alarm. The virus continues to evolve, but so too does our understanding and our ability to respond. With careful monitoring, vaccination, and sensible precautions, the UK is facing this new phase with a blend of caution and calm resilience.
