Cases of the so-called 'American Covid' variant, officially named XFG or 'Stratus', are on the rise in the UK. The strain is the most common variant in North America, hence its nickname, but it now accounts for more than half of positive Covid tests in the UK, according to new figures.
The rate of positive Covid tests in hospitals increased from 5.9% to 7.0% as of Thursday, the UK Health Security Agency (UKHSA) said. Hospital admissions have also risen by almost 50%, with London seeing the highest increase at 79%.
What is the 'American coronavirus'?
Viruses change over time to survive, and SARS-CoV-2 is no different. When a virus changes substantially – a mutation – scientists call it a variant. Viruses that inherit a beneficial mutation may outcompete others.
Dr Alex Allen, a consultant epidemiologist at the UKHSA, 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.'
This refers to the Omicron variant, which emerged in 2021. Omicron has sharper spikes to latch onto human cells and can better avoid antibodies. XFG is the latest spinoff of Omicron, a combination of two offspring (LF.7 and LP.8). Public officials named it Stratus, after low-hanging grey clouds. The strain was first designated in 2025, so it isn’t new, but it is behind the recent increase in UK cases.
What are the symptoms of American Covid?
The most common Covid symptoms haven’t changed much since the start of the pandemic: congestion, cough, fever, headache, runny nose, muscle aches, and a sore, hoarse throat. That last symptom, a scratchy throat, seems to be the most unique distinguishing XFG from other strains, experts say.
While Covid is mild for most people, it can be dangerous and even fatal for some. The NHS stresses that if you test positive, stay home for at least five days if you’re over 18 and three days if younger.
Could it cause another pandemic?
Experts said earlier this year that the 'American coronavirus' probably won’t cause another pandemic. Rather, this strain shows that we now have to 'coexist' with Covid, a bit like the common cold.
Dr Allen stressed that Britons don’t have a reason to stock up on toilet roll anytime soon. 'While Covid-19 activity has shown some recent increases, cases remain at low levels in the UK,' he said. '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.'
How many people have died from American Covid?
Health agencies, even big ones like the World Health Organization, don’t tend to publish Covid death numbers for each variant. Most fatalities are confirmed with a simple Covid test, rather than zooming in on the virus to see.
'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 Allen added.
How can I avoid catching Covid?
Covid is spread from person to person through tiny viral droplets of mucus or saliva, ejected when a sick person coughs, sneezes, breathes or talks. The droplets need to enter a person’s eyes, nose or mouth to spread. It doesn’t linger in the air for long enough to be a risk.
As so many people in the UK are vaccinated, we don’t need to do public health measures like lockdowns or social distancing. Vaccines are also effective against the American Covid variant. Washing your hands is one of the best ways to avoid Covid, and cleaning 'high-touch' surfaces such as mobile phones and bathroom door handles is recommended. The UKHSA recommends you get a Covid jab, cover your mouth when coughing and, if you’re feeling unwell, stay at home.
