More than 200 symptoms of long Covid have been identified in an international study.
Among the most common symptoms were fatigue and brain fog.
The diverse range of symptoms included visual hallucinations, tremors, itchy skin, changes to the menstrual cycle, sexual dysfunction, heart palpitations, bladder control issues, shingles, memory loss, blurred vision, diarrhoea and tinnitus.
Dozens of symptoms, revealed in the largest international study of "long-haulers" to date, lingered for at least seven months.
Respondents with symptoms over six months experienced an average of 13.8 symptoms in month seven. During their illness, participants experienced an average of 55.9 symptoms.
The study by University College London, published in The Lancet’s EClinicalMedicine, also examined the effects on daily life, work and return to health. It included 3,762 eligible participants from 56 countries.
The research team, who have all had or continue to have long Covid, are now calling for clinical guidelines on assessing long Covid to be widened beyond currently advised cardiovascular and respiratory function tests to include neuropsychiatric, neurological and activity intolerance symptoms.
They called for a national screening programme in the UK, accessible to anyone who thinks they have long Covid, to try to detect the root cause of suffering and provide the correct treatment.
It has previously been estimated that two million people in England have had long Covid.
Senior author Dr Athena Akrami, neuroscientist at the Sainsbury Wellcome Centre at UCL, said: “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.”
The survey was open to people aged 18 or over who had experienced symptoms consistent with Covid-19, including those with and without a positive SARS-CoV-2 test. It consisted of 257 questions.
While the study did not estimate how common long Covid is, other studies have estimated that one in seven people have some symptoms 12 weeks after a positive test result, or almost 30 per cent of people 12 weeks after symptomatic disease.
The probability of symptoms lasting beyond 35 weeks was 91.8 per cent. Of the 3,762 respondents, 96 per cent reported symptoms beyond 90 days, 2,454 experienced symptoms for at least 180 days and only 233 had recovered.
“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," Dr Akrami said.
“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 substantial impact on work.
“Along with the well-documented respiratory and cardiovascular symptoms, there is now a clear need to widen medical guidelines to assess a far wider range of symptoms. Furthermore, there are likely to be tens of thousands of long Covid patients suffering in silence, unsure that their symptoms are connected to Covid-19.”