More than two million people in England are thought to have had one or more Covid-19 symptoms lasting at least 12 weeks, one of the largest studies of the virus suggests.
Long Covid is more common among women, people who are overweight or obese, smokers, those living in deprived areas and those admitted to hospital, the Imperial College London study showed.
One fifth of those surveyed reported having experienced Covid-19 symptoms.
About 37 per cent told of at least one persistent symptom lasting and almost 15 per cent said they had three or more symptoms for at least 12 weeks.
“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," director of the programme Prof Paul Elliott said.
“Long Covid is still poorly understood but we hope through our research that 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.”
The findings suggest prevalence of long Covid increases with age, with a 3.5 per cent rise in likelihood with each decade of life.
People with persistent symptoms at 12 weeks fell into two groups. In the first, the most common symptom was tiredness and muscle aches.
In the second, the most common symptoms were shortness of breath affecting normal activities, tightness in chest, and chest pain, with more people reporting they had severe symptoms.
Persistent Covid-19 symptoms were lower in people of Asian ethnicity.
“Long Covid can have a lasting and debilitating impact on the lives of those affected," Health Secretary Matt Hancock said.
"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 ($69.8m) of research funding available to support innovative projects, with clinics established across the country to help improve the treatment available.”
The government is providing the £50m through the UK Research and Innovation and the National Institute for Health Research to ensure the best treatments are available.
The National Health Service has opened more than 80 long-Covid assessment services in England.
Last week the NHS published a £100m plan to expand support, including £30m to help GPs improve diagnosis and care for patients with long Covid.
Funded by the government, the React-2 study was based on self-reported data from 508,707 adults who took part between September 2020 and February 2021.
Because many of the symptoms are not specific to Covid-19, the the prevalence of such symptoms after recovery from the disease may have been overestimated.
