The XFG Covid strain, also known as Stratus or American Covid, has become dominant in Britain, accounting for more than half of positive tests in September. Latest figures from the UK Health Security Agency (UKHSA) show Covid cases have increased hospital admissions by over 400 per cent, putting further strain on the NHS.
Last month, cases jumped to 4,589 from 1,374 in August, with those now needing a hospital bed hitting almost 5,000. More than half of the positive tests which led to hospitalisation were attributed to the XFG variant. The strain is believed to be behind a steep rise in infections reported to the UKHSA, with a 230 per cent jump to 4,589 inside four weeks.
What is 'American Covid'?
XFG is the most common Covid variant in North America, which has led to it being dubbed "American Covid". The strain now accounts for more than half of positive Covid tests in the UK, according to the latest figures. XFG has been circulating in Europe and North America since the end of 2025. The World Health Organisation identified it as a mix of earlier variants LF.7 and LP.8.1.2. The strain is an offshoot of Omicron, which emerged in 2021.
UKHSA's Dr Alex Allen, a consultant epidemiologist, 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."
The new symptoms and steps to take
Much like Covid, a blocked or runny nose, a headache, high temperature or shivering are all signs to look out for. But hallmark symptoms of the new variant also include a persistent, dry cough, fatigue or general tiredness, and a high temperature of 38C+. It may present with more than half a dozen other signs, ranging from a scratchy, sore throat to bouts of diarrhoea. UKHSA says Covid symptoms have changed over time, with many people now experiencing cold-like symptoms.
Those who fear they may have contracted the virus have been advised to avoid contact with other people for at least five days, with anyone younger than age 18 asked to wait at least three days. Anyone who tests positive should avoid meeting with anyone who has a weakened immune system for at least 10 days after the day the results came back. If a child has mild symptoms such as a runny nose, sore throat or mild cough, and feels well enough, they can go to school or childcare.
Could it cause another pandemic?
Experts said earlier this year that this particular strain shows that we now have to just 'coexist' with Covid, a lot like the common cold. Health officials are urging eligible people to get their Covid and flu vaccines ahead of the winter months, when respiratory viruses can circulate at high levels.
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. We're also not seeing any evidence that these are making people more ill or spreading faster than before, and this year's autumn vaccine has been specifically designed to protect against them."
