Almost 400,000 people in the UK have reported having symptoms of long Covid for at least a year after their initial infection, data suggests, as new figures show coronavirus infection rates are once again rising in England. This represents a marked increase in the number of people with self-reported long Covid that has lasted for at least a year, according to the Office for National Statistics. Data published by the ONS on Friday shows 376,000 people in private households in the UK have experienced symptoms of long Covid for at least 12 months, up from 70,000 in early March. Symptoms of the often debilitating condition known as long Covid include fatigue, muscle pain and “brain fog”. The ONS estimates 1 million people in private households in the UK were experiencing symptoms of long Covid in the four weeks to 2 May. About 650,000 people had their day-to-day activities affected by long Covid, with 192,000 of these saying this had been limited a lot. “As a proportion of the UK population, prevalence of self-reported long Covid was greatest in people aged 35 to 69, females, those living in the most deprived areas, those working in health or social care, and those with another activity-limiting health condition or disability,” the ONS said. Other data published on Friday by the ONS, which conducts a survey based on swabs from randomly selected households, reveals that an estimated 85,600 people within the community in England had Covid in the week ending 29 May – around one in 640 people – compared with 48,500 people, or one in 1,120, the week before. This equates to an increase of roughly 75% on estimated cases from the previous week. The picture varies by region. “In the week ending 29 May 2021, the percentage of people testing positive has increased in the north-west, east Midlands and the south-west,” the report notes, adding there are also signs of a possible rise in London and the West Midlands. The picture also varies by age, with increases seen in people 35 and over and in secondary school-age children. Sarah Crofts, the head of analytical outputs for the Covid-19 Infection Survey, said the figures suggested the situation was mixed across the UK. “Although infections remain low, the percentage of those testing positive for Covid-19 has increased slightly in England and we are seeing early signs of an increase in Wales. The trends are uncertain in Northern Ireland and Scotland,” she said. “We are also seeing an increase in England in the percentage of cases compatible with the Delta variant first identified in India. Analysing these trends will be key over the next few weeks as we monitor the impact of the variants in different regions.” The Scientific Advisory Group for Emergencies (Sage) has estimated the R number of England – the average number of people an infected person will pass the virus to – at 1.0 to 1.2. The rise of the Delta variant, also known as B.1.617.2, has caused concern among some scientists, with the latest data suggesting it is not only more transmissible than the Alpha variant first detected in Kent, B.1.1.7, but also somewhat more resistant to Covid vaccines, particularly after the first jab. What’s more, early data released by Public Health England on Thursday suggested it could be more than twice as likely to lead to hospitalisations than the Alpha variant, although further research is needed to confirm this and explore links to vaccination status. Experts have cautioned that rising numbers of infections may not only lead to a rise in hospitalisations – albeit it lower than would be expected without the vaccine programme – but that there could be other effects, including disruption to NHS services and a rise in cases of long Covid. Dr David Strain, a senior clinical lecturer at the University of Exeter, said the long Covid figures showed “the devastating longer-term impact” of Covid and emphasised the importance of vaccination. “Our recent work has demonstrated that the majority of people suffering with long Covid benefit from vaccination, and clearly the best way to prevent long Covid is to not get Covid in the first instance,” he said. Strain added that the rise in infection rates was occurring when numbers would have been expected to rise after the 17 May easing of lockdown, and the next few weeks would be crucial to determine whether the rate of vaccination, and the protection that this gives against the new variants, will be enough to counter the impact of these relaxations. “ The concern is that the Delta variant is currently infecting a population that had a low prevalence of Covid from the Alpha variant,” he said. “If this is a true increase in transmissibility of the variant, rather than being purely due to this population being at higher risk because they have not been vaccinated as yet, this could lead to a greater impact in the future of long Covid and the wider economy that will be dependent on these individuals being able to work to full efficiency.”