Nearly one in seven Britons who tested positive for Covid-19 continued to have symptoms for at least 12 weeks, a UK study released on Thursday suggested.
The Office for National Statistics said the study of more than 20,000 people who tested positive from April 2020 to March 2021 found 13.7 per cent had symptoms that lasted for at least 12 weeks.
This was based on self-reported symptoms of "long Covid". The list of 13 symptoms included fatigue, muscle pain and difficulty concentrating, as well as loss of taste and smell.
Women were more more likely (14.7 per cent) to report long-lasting symptoms than men (12.7 per cent).
Those aged between 35 and 49 were most likely to report symptoms at five weeks (25.6 per cent).
The study of UK patients was based on a random sample of 21,622 participants who tested positive from swabs and were asked about their symptoms each month.
A control group who were unlikely to have been infected was also set up.
It found they were eight times less likely to have such symptoms.
In a larger survey, 1.1 million people reported long Covid over the four weeks ending on March 6, 2021, the ONS said.
Ben Humberstone, head of health analysis and life events at the ONS, said this was its first analysis of new data and "our understanding of it, and its quality will improve over time".
Long Covid "is an emerging phenomenon that is not yet fully understood", Mr Humberstone said.
Britain, one of the countries worst hit by the pandemic, has recorded almost 127,000 deaths from Covid and 4,350,266 cases.
But the number of daily deaths and positive tests have fallen steadily during a strong vaccination campaign.