Long Covid has more than 200 symptoms including hallucinations, shingles and the loss of bladder control, a study has found.
The latest figures from the Office for National Statistics indicate that around one in seven patients experience symptoms that persist for more than 12 weeks after a positive Covid test.
The long-term nature of the condition means it has been difficult to get conclusive data on exactly what it is, what causes it and how it manifests.
A team of academics led by University College London gave a questionnaire to more than 3,700 Covid "long haulers" from 56 countries, with 257 questions asking them to list and describe their symptoms.
The results indicate that there are 203 individual symptoms affecting 10 different organ systems. Fatigue was the most common, followed by post-exertional malaise and brain fog.
The complete list includes visual hallucinations, tremors, itchy skin, changes to the menstrual cycle, sexual dysfunction, heart palpitations, bladder control problems, shingles, memory loss, blurred vision, diarrhoea and tinnitus.
Dr Athena Akrami of UCL, the senior author of the study, said: "While there has been a lot of public discussion around long Covid, there are few systematic studies investigating this population.
"Hence relatively little is known about its range of symptoms and their progression over time, the severity, and expected clinical course, its impact on daily functioning and expected return to baseline health.
"In this unique approach, we have gone directly to ‘long haulers’ around the world in order to establish a foundation of evidence for medical investigation, improvement of care, and advocacy for the long Covid population. This is the most comprehensive characterisation of long Covid symptoms so far."
All the other study authors have either had Covid or continue to grapple with debilitating symptoms.
The average number of symptoms for people who have had long Covid for more than three months was 17, with the majority saying their recovery was plagued by relapses.
Almost half – 45.2 per cent – were not working the same hours as they had been before becoming ill with the virus, and 22.3 per cent were not working at the time of the survey.
Dr Akrami said: "For the first time, this study shines a light on the vast spectrum of symptoms, particularly neurological, prevalent and persistent in patients with long Covid.
"Memory and cognitive dysfunction, experienced by over 85 per cent of respondents, were the most pervasive and persisting neurologic symptoms, equally common across all ages, and with a substantial impact on work.
"We now believe a national programme could be rolled out into communities able to screen, diagnose and treat all those suspected of having long Covid symptoms."
The full scale of long Covid remains unknown and there is debate over what the criteria and threshold should be. In its latest bulletin, the ONS said the condition was "an emerging phenomenon that is not yet fully understood".
However, it is estimated that around one million people in the UK have long Covid – around 1.5 per cent of the population.