American Covid strain symptoms are back in focus as XFG, also called Stratus, pushes up positive tests and hospital admissions in the UK. The rate of positive Covid tests in hospitals rose from 5.9% to 7.0% as of Thursday.
Hospital admissions have risen by almost 50%, and London saw the biggest increase at 79%. People in the UK are seeing a variant that now accounts for more than half of positive tests, even as Dr Alex Allen says the strains now circulating are not something new.
UKHSA on XFG
Dr Alex Allen, a consultant epidemiologist at the UK Health Security Agency, said: “The strains currently going around, including those known as XFG, are closely related to strains that have been with us for over a year, so this isn’t something new.”
That puts XFG in a familiar line of SARS-CoV-2 change rather than a sudden break from what came before. XFG is the latest spinoff of Omicron, and the strain was first designated in 2025.
What XFG means
The X in XFG means the strain is a combination of two offspring, LF.7 and LP.8. FG is a sequence used to track viruses. Public officials named the strain Stratus after low-hanging grey clouds.
Cases of so-called American Covid are rising in the UK while XFG remains the most common variant in North America. That spread matters for people in the UK because the hospital data points to more infections moving far enough through the system to show up in admissions, not just positive tests.
London and hospital admissions
London’s 79% increase stands out against the national rise of almost 50%, showing the pressure is uneven rather than uniform. The same strain can therefore look different from place to place, with hospital admissions climbing faster in London than across the UK overall.
The most distinctive symptom linked to XFG appears to be a scratchy throat that makes people sound croaky. The most common Covid symptoms have not changed much since the start of the pandemic, so the practical change for people in the UK is not a brand-new symptom list but a variant that is spreading more widely and landing more people in hospital.
For anyone watching for American Covid strain symptoms, the immediate read is simple: XFG is circulating widely, hospital test positivity has moved up, and the sharpest hospital rise is in London. The next step for readers is to track symptoms early and treat a croaky scratchy throat as a possible sign rather than assuming the illness will look different from older Covid infections.
