More than two million people may have suffered from long Covid, a government-backed study has found.
The research found that more than one third of people in England who had Covid reported symptoms lasting at least 12 weeks.
That amounts to 5.8 per cent of the whole study population, with two per cent reporting severe symptoms. Researchers found that the prevalence of long Covid increased with age and was higher among women.
The findings are based on self-reported data from 508,707 adults aged 18 and over who took part in rounds three to five of Imperial College London’s React-2 study, carried out between September and February.
Around a fifth of those surveyed reported having had a virus symptom previously, with more than a third reporting persistent symptoms lasting at least 12 weeks. Around a tenth of those with symptoms said they lasted at least 12 weeks and were severe.
Researchers say the findings suggest the prevalence of persistent symptoms, or long Covid, increases with age, with a 3.5 per cent increase in likelihood in each decade of life.
The study, yet to be peer-reviewed, indicates that long Covid is higher among women, people who are overweight or obese, those who smoke, live in deprived areas or who had been admitted to hospital. According to the research, persistent Covid symptoms were lower in people of Asian ethnicity.
Prof Paul Elliott, the director of the React programme at Imperial, said: "Our findings do paint a concerning picture of the longer-term health consequences of Covid-19, which need to be accounted for in policy and planning.
"Long Covid is still poorly understood, but we hope that through our research we can contribute to better identification and management of this condition, which our data and others’ suggest may ultimately affect millions of people in the UK alone."
People with persistent symptoms at 12 weeks fell into two broad groups, researchers found.
In the first, the most common symptoms were tiredness and muscle aches. The most common symptoms in the second group were shortness of breath affecting normal activities, tightness in the chest and chest pain, with more people reporting that they had severe symptoms.
But the study was based on self-reported data and, because many of the symptoms are common and not specific to the virus, it may overestimate the prevalence of persistent symptoms following Covid.
Matt Hancock, the Health Secretary, said: "Long Covid can have a lasting and debilitating impact on the lives of those affected.
"Studies like this help us to rapidly build our understanding of the impact of the condition, and we are using these findings and other new research to develop support and treatments.
"We are learning more about long Covid all the time and have made £50 million of research funding available to support innovative projects, with clinics established across the country to help improve the treatment available."
To aid people suffering debilitating long-term effects, the NHS has opened more than 80 long Covid assessment services across England.
Last week, the health service published a £100 million plan to expand support, including £30 million to help GPs improve diagnosis and care for patients with long Covid.