This is the most comprehensive characterisation of long COVID symptoms, so far" Dr Athena Akrami, Group Leader, SWC

Identification of over 200 long COVID symptoms prompts call for UK screening programme

15 July 2021

Patients who experience long COVID have reported more than 200 symptoms across 10 organ systems*, in the largest international study of ‘long-haulers’ to date, led by UCL scientists together with the Patient-Led Research Collaborative

Dr Athena Akrami, neuroscientist and Group Leader at Sainsbury Wellcome Centre, UCL, shares her personal journey with long-COVID and how she came together with other researchers to develop the Patient-Led Research Collaborative to collect data on those with COVID-19 prolonged recoveries. This is the most comprehensive study of 'long-haulers' to date and the results have been published in the Lancet's EClinicalMedicine.

For the study, published in the Lancet’s EClinicalMedicine, patient researchers who connected through the Body Politic online COVID-19 support group created a web-based survey designed to characterise the symptom profile and time course in patients with confirmed or suspected long COVID, along with the impact on daily life, work, and return to health.

With responses from 3,762 eligible participants from 56 countries, the researchers identified a total of 203 symptoms in 10 organ systems; of these, 66 symptoms were tracked for seven months. The most common symptoms were fatigue, post-exertional malaise (the worsening of symptoms after physical or mental exertion), and cognitive dysfunction, often called brain fog.

Of the diverse range of symptoms, others included: visual hallucinations, tremors, itchy skin, changes to the menstrual cycle, sexual dysfunction, heart palpitations, bladder control issues, shingles, memory loss, blurred vision, diarrhea, and tinnitus.

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 significantly widened beyond currently advised cardiovascular and respiratory function tests to include neuropsychiatric, neurological, and activity intolerance symptoms.

Furthermore, with large numbers of long haulers ‘suffering in silence’, the authors advocate that a national screening programme, accessible to anyone who thinks they have long COVID, should be undertaken. Given the heterogeneous (diverse) make-up of symptoms that affect multiple organ systems, it is only by detecting the root cause that patients will receive the correct treatment.

Explaining the study, senior author Dr Athena Akrami (neuroscientist at the Sainsbury Wellcome Centre at UCL) 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 (longevity), 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.”

The survey was open to those aged 18 or over who had experienced symptoms consistent with COVID-19, including those with and without positive SARS-CoV-2 test. It consisted of 257 questions.

In order to characterise long COVID symptoms over an extended duration, analysis of survey data was limited to respondents with illnesses lasting longer than 28 days and whose onset of symptoms occurred between December 2019 and May 2020, allowing analysis of symptoms from week one to month seven.

While the study did not estimate how common long COVID is overall, other studies have estimated that one in seven people have some symptoms 12 weeks after a positive test result (from the Office for National Statistics), or almost 30% of people 12 weeks after symptomatic disease (from Imperial College London’s REACT study).

Survey summary
In this long COVID cohort, the probability of symptoms lasting beyond 35 weeks (eight months) was 91.8%. Of the 3,762 respondents, 3,608 (96%) reported symptoms beyond 90 days, 2,454 (65%) experienced symptoms for at least 180 days (six months) and only 233 had recovered.

In those who recovered in less than 90 days, the average number of symptoms (11.4 out of 66 symptoms that were measured over time) peaked at week two, and for those who did not recover in 90 days, the average number of symptoms (17.2) peaked at month two. 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 (out of the longer list of 203 measured in the study), across an average of 9.1 organ systems.

89.1% of participants experienced relapses, with exercise, physical or mental activity, and stress as the main triggers. 45.2% reported requiring a reduced work schedule compared to pre-illness and 22.3% were not working at all 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% of respondents, were the most pervasive and persisting neurologic symptoms, equally common across all ages, and with substantial impact on work.

“Headaches, insomnia, vertigo, neuralgia, neuropsychiatric changes, tremors, sensitivity to noise and light, hallucinations (olfactory and other), tinnitus, and other sensorimotor symptoms were also all common, and may point to larger neurological issues involving both the central and peripheral nervous system.

“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 when diagnosing long COVID. 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. Building on the network of long COVID clinics, which take GP referrals, we now believe a national programme could be rolled out into communities able to screen, diagnose and treat all those suspected of have long COVID symptoms.”

The research team’s future work will focus on emerging topics in long COVID: mental health outcomes, diagnostic and antibody testing, symptom clustering, and socioeconomic impact from the illness.

Study limitations
There are several limitations to this study. First, the retrospective nature of the study exposes the possibility of recall bias. Second, as the survey was distributed in online support groups, there exists a sampling bias toward long COVID patients who joined support groups and were active participants of the groups at the time the survey was published. Additionally, despite eight translations and inclusive outreach efforts, the demographics were strongly skewed towards English speaking (91.9%), white (85.3%) respondents.

Notes to editors and additional details

For more information or to speak to the researchers involved, please contact 

Read the full paper in the Lancet's EClinicalMedicine

Hannah E. Davis, Gina S. Assaf, Lisa McCorkell, Hannah Wei, Ryan J. Low,  Yochai Re’em, Signe Redfield, Jared P. Austin, and Athena Akrami, ‘Characterizing Long COVID in an International Cohort: 7 Months of Symptoms and Their Impact’ DOI: 10.1101/2020.12.24.20248802


Additional information

* 10 Organ systems (refer to Appendix A of the paper): Systemic: fatigue, temperature, weakness, post-exertional malaise; Neuropsychiatric (sub-categories): Cognitive Functioning, Memory, Speech and Language, Neurological Sensations, Sleep, Headaches, Emotion and Mood, Taste and Smell, Hallucinations; Cardiovascular: heart related, Dermatologic: skin related Gastrointestinal: bowel/appetite-related symptoms; Pulmonary and Respiratory: breathing related; Head, Ear, Eye, Nose, Throat (HEENT): both physical and sensory symptoms to HEET; Reproductive, Genitourinary, and Endocrine: symptoms related to menstruation, thirst and urinary function, and low and high blood sugar; Immunologic and Autoimmune: new and heightened immune responses; Musculoskeletal: chest tightness and aches and pain throughout the musculoskeletal system.

Symptom prevalence – summary
Top three symptoms: Fatigue 98.3%, post-exertional malaise (PEM) 89.0%, and brain fog and cognitive dysfunction in 85.1% (3,203) of respondents.

The top three most debilitating symptoms listed by patients were: fatigue (2,652 patients), breathing issues (2,242), and cognitive dysfunction (1,274).

Symptoms remaining at six months
A total of 2,454 (65.2%) respondents were experiencing symptoms for at least six months. Over 50% experienced the following symptoms: fatigue (80%) post-exertional malaise (73.3%), cognitive dysfunction (58.4%), sensorimotor symptoms (55.7%), headaches (53.6%), and memory issues (51%). In addition, between 30%-50% of respondents were experiencing the following symptoms after six months of symptoms: insomnia, heart palpitations, muscle aches, shortness of breath, dizziness and balance issues, sleep and language issues, joint pain, tachycardia, and other sleep issues.
About UCL – London’s Global University
UCL is a diverse community with the freedom to challenge and think differently.

Our community of more than 41,500 students from 150 countries and over 12,500 staff pursues academic excellence, breaks boundaries and makes a positive impact on real world problems.

We are consistently ranked among the top 10 universities in the world and are one of only a handful of institutions rated as having the strongest academic reputation and the broadest research impact. 

We have a progressive and integrated approach to our teaching and research – championing innovation, creativity and cross-disciplinary working. We teach our students how to think, not what to think, and see them as partners, collaborators and contributors.  

For almost 200 years, we are proud to have opened higher education to students from a wide range of backgrounds and to change the way we create and share knowledge. 

We were the first in England to welcome women to university education and that courageous attitude and disruptive spirit is still alive today. 

We are UCL. | Follow @uclnews on Twitter | Watch our YouTube channel | Listen to UCL podcasts on SoundCloud | Find out what’s on at UCL Minds | #MadeAtUCL

Find out how UCL is helping lead the global fight against COVID-19

About the Sainsbury Wellcome Centre at UCL
The Sainsbury Wellcome Centre (SWC) brings together world-leading neuroscientists to generate theories about how neural circuits in the brain give rise to the fundamental processes underpinning behaviour, including perception, memory, expectation, decisions, cognition, volition and action. Funded by the Gatsby Charitable Foundation and Wellcome, SWC is located within UCL and is closely associated with the Faculties of Life Sciences and Brain Sciences.