Cases of the XFG variant, also known as the Stratus or “American Covid” strain, are climbing in England, pushing hospital admissions and test positivity rates higher. The UK Health Security Agency reported that positive test rates in hospitals rose from 5.9 % to 7.0 % in September, while admissions increased by almost 50 % nationally, with London seeing a 79 % jump. More than half of the positive samples identified the XFG lineage, a blend of earlier LF.7 and LP.8.1.2 variants first detected in January 2026. Health officials urge eligible groups to take the autumn Covid‑19 vaccine, which has been updated to target this strain, and remind the public to follow isolation guidance if they test positive.
Rising Test Positivity and Hospital Pressure
The latest UKHSA surveillance shows hospital test positivity climbing to 7.0 % from 5.9 % in September, a clear upward trend. Hospital admission rates have surged by nearly 50 % compared with the previous period, reflecting more patients needing inpatient care. In London, the increase is even steeper at 79 %, highlighting regional variation in the current wave. Despite these rises, officials stress that overall case numbers remain low compared with earlier pandemic peaks.
Variant Characteristics and Expert Insight
Genetic sequencing revealed that over half of the positive specimens were the XFG (Stratus) variant, which the World Health Organisation has classified as a recombination of LF.7 and LP.8.1.2. First identified in January 2026, the strain has now circulated for a year, prompting the UKHSA to note that this winter’s vaccine is specifically formulated to protect against it and its close relatives. Experts acknowledge the increase but caution against alarm.
Alex Allen, consultant epidemiologist at the UKHSA, said: “While Covid-19 activity has shown some recent increases, cases remain at low levels in the UK.“UKHSA is monitoring all the data relating to Covid-19 variants in the UK and abroad, and we continue to publish our findings in our regular surveillance reports.”
Dr Matthew Siggins, lecturer in immunity and infection biology at the University of Surrey, added: “There is no evidence that variants currently circulating in the UK are causing more severe disease,” he told The Independent. “However, Covid can still cause serious illness in those at greatest risk.” He also noted that those over 85 are most likely to be hospitalised, with rates climbing to 12.43 per 100,000 from 7.08 the previous week.
Dr Siggins further commented: “Covid is increasing, which is not unexpected for this time of year, but remains at a low level. Waning immunity, changes in circulating variants, as well as increased indoor mixing can all contribute to increasing rates of infection.”
Paul Hunter, professor of medicine at the University of East Anglia, observed: “Reported infections and hospitalisation are still quite a lot lower than this time last year.”
Clinical observers note that symptoms linked to the XFG lineage resemble those of other recent variants—sore throat, cough, fatigue, and fever—while Dr Bruno Silvester Lopes, lecturer in microbiology at Teesside University, highlighted that Stratus was “linked to hoarseness and fatigue”.
Vaccination Guidance and Public Health Advice
The NHS continues to advise that most people no longer need routine lateral flow testing, but anyone with a positive result should stay at home and avoid contact with others for five days, or three days for those under 18. Individuals who test positive should also refrain from meeting anyone with a weakened immune system for ten days after the test date. Vaccination remains the cornerstone of protection, especially for people aged 75 and over, care‑home residents, and immunosuppressed individuals. The autumn booster programme has been updated to target the Stratus strain, and health officials urge eligible groups to come forward for their jab promptly.
Why it Matters
The resurgence of the XFG (Stratus) variant serves as a reminder that SARS‑CoV‑2 continues to evolve, and even modest rises in transmission can translate into noticeable pressure on hospitals, particularly for the oldest and most vulnerable. While current levels remain far below the crisis peaks of early 2021, the upward trend in admissions and the strain’s specific symptoms underscore the importance of maintaining vaccination coverage, heeding isolation advice, and protecting those at highest risk through timely boosters and prudent social behaviour.
