With COVID activity increasing this autumn, the nickname “American Covid” has attracted attention. But the variant behind the headlines, XFG, has circulated in the UK for around a year.

The UK Health Security Agency (UKHSA) explains that the nickname refers to where the variant was first detected and sequenced—not proof of where it originated. Media reports also sometimes call XFG “Stratus.”

In its update published on 8 October 2026, UKHSA reported that Covid test positivity reached approximately 7% in September, while hospital admission rates increased by about 50% during that month. These measures reflect positive tests and hospital activity; they do not count everyone infected.

Despite the increase, UKHSA says current evidence does not suggest that circulating variants cause more severe illness than other variants. More time spent indoors and waning immunity may be contributing to the rise.

Covid symptoms can resemble a cold or flu. They include fever, persistent coughing, fatigue, breathlessness, headaches, body aches, a sore throat and a blocked or runny nose. Changes in taste or smell, reduced appetite, nausea, vomiting and diarrhea can also occur.

For people with symptoms, NHS advice is to stay home and limit contact with others if they have a fever or feel too unwell for their usual activities.

A positive test brings more specific advice:

Adults aged 18 and over: try to stay home and avoid others for five days after the test date.

Under-18s: the recommended period is three days after the test date.

All ages: avoid meeting people at greater risk of serious illness, including those with weakened immunity, for ten days after the test date.

Most people with symptoms do not need a lateral flow test. However, anyone eligible for COVID treatment should test promptly when symptoms begin. Contact a GP or NHS 111 if symptoms worsen or fail to improve. Severe breathing difficulty or sudden chest pain requires emergency help.

To reduce transmission, UKHSA advises people who are unwell and cannot stay home to wear a well-fitting mask and avoid crowded or poorly ventilated spaces. Eligible people are also encouraged to get vaccinated to help protect against severe illness.