Hospital admissions for Covid in the UK have risen sharply, with the latest "American Covid" strain taking hold. Figures from the UK Health Security Agency show the proportion of hospital Covid tests coming back positive has increased from 5.9% to 7%.
In London, Covid-related hospital admissions have climbed by almost 80% in seven days. Among the over-85s, admissions have risen from 7.08 to 12.43 per 100,000.
Strain XFG dominates infections
The strain currently dominating infections is XFG, commonly known as Stratus and nicknamed "American Covid". First detected in January 2025, it has since spread in both the UK and US.
Symptoms remain similar to those associated with Covid, including coughs, fever, sore throats, headaches, runny noses and fatigue. Some doctors have also reported gastrointestinal problems among patients with the latest strain.
Doctors report flu-like illness
Dr Matthew Siggins, lecturer in immunity and infection biology at the University of Surrey, said the rise was "not unexpected at this time of year". He said weekly hospital admissions in England had increased from 0.81 to 1.20 per 100,000, but stressed this was still considered a baseline level.
London GP Dr Renee Hoenderkamp said she had noticed a clear change in the patients visiting her surgery. "In the past ten days to three weeks in general practice my lists have definitely changed to people with these symptoms," she told Daily Mail.
She described the illness as "very flu-like", adding that most people were likely to experience manageable symptoms. However, some patients have been hit much harder, with reports of severe fatigue, high temperatures, painful aches and prolonged illness.
Immunity and surveillance
Despite the rise in infections and admissions, experts have stressed that the current situation is very different from the height of the pandemic. The latest available UKHSA figures showed seven registered deaths involving Covid in England in the week ending August 28, compared with six the previous week. By comparison, 61 deaths were recorded in a week in mid-January earlier this year.
Dr Hoenderkamp said most otherwise healthy people had little reason to be alarmed and advised those with a high temperature or who felt particularly unwell to stay at home, as they would with flu. Experts also say widespread immunity from previous infections and vaccinations is helping protect people against severe disease.
Dr Siggins said most people still had "substantial immunity" but warned that protection against infection could fade over time. Professor Emma Wall, a clinical professor of infectious diseases at Queen Mary University of London, said most people already had some pre-existing immunity to new Covid variants. However, she warned that repeated infections could increase the risk of Long Covid, with some patients developing the condition after their fourth or fifth infection.
Scientists are also keeping a close eye on the possibility of several winter viruses circulating at the same time. In December 2024, hospitals faced a major surge in flu, Covid, RSV and norovirus, putting significant pressure on NHS capacity. Professor Wall said surveillance remained important as Covid continued to evolve alongside traditional winter viruses. "We remain under surveillance," she said. "That helps us work out who needs to be vaccinated and with which vaccine."
