Nearly 400,000 people have suffered long Covid symptoms for more than 12 months, the latest data from the Office for National Statistics (ONS) shows.
Based on a survey of private households in the UK, the ONS estimated that around 962,000 people have experienced persistent symptoms such as fatigue, shortness of breath, muscle aches and difficulty concentrating since contracting the virus.
Long Covid is defined as experiencing symptoms for at least four weeks after recovering from an infection.
Four in 10 people – 385,000 – said they were still suffering problems even though they had caught the virus more than a year ago.
Two-thirds of long Covid sufferers said the aftermath ffected their day-to-day activities, with nearly one in five saying their lives were "limited a lot".
Fatigue was the most common symptom reported, followed by shortness of breath. People aged 35 to 69 were the most likely to report long Covid symptoms, with women and those with disabilities also over-represented.
Fatigue was the most common symptom reported as part of individuals’ experience of long Covid
Overall there are slightly fewer people reporting long Covid than in the previous survey, when more than a million complained of symptoms. However experts said the recent rise in infections was likely to trigger more cases.
Dr Elaine Maxwell, scientific adviser at the National Institute for Health Research, said: "It is likely that the recent rise in infections will see an increase in long Covid lasting four weeks in the next ONS release.
"By the autumn/winter of 2021, we should expect to see a sharp rise in those reporting symptoms for at least 12 months mirroring [second wave] infections.”
Previous research has estimated that as many as two million people in England could be suffering ongoing symptoms after a Covid infection.
Experts from Oxford University and the London School of Hygiene and Tropical Medicine said their study raised questions about how long Covid is diagnosed, recorded and managed in the NHS.
They found that between February 2020 and April this year, only 23,273 cases were formally recorded at GP practices in England. More than a quarter of practices (26.7 per cent) had never logged a case, according to the article in the British Journal of General Practice.
Academics suggested there could be a number of reasons for the findings, including patients not yet seeing a GP about symptoms, doctors having different diagnostic thresholds or criteria, and issues around how the diagnosis is recorded in GP computer systems.