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Fatigue is the most commonly reported symptom in patients with persistent complaints following COVID-19 (ie, long COVID). Longitudinal studies examining the intensity of fatigue and differentiating between physical and mental fatigue are lacking.
The objectives of this study were to (1) assess the severity of fatigue over time in members of online long COVID peer support groups, and (2) assess whether members of these groups experienced mental fatigue, physical fatigue, or both.
A 2-wave web-based follow-up study was conducted in members of online long COVID peer support groups with a confirmed diagnosis approximately 3 and 6 months after the onset of infectious symptoms. Demographics, COVID-19 diagnosis, received health care (from medical professionals or allied health care professionals), fatigue (Checklist Individual Strength–subscale subjective fatigue [CIS-Fatigue]; 8-56 points), and physical and mental fatigue (self-constructed questions; 3-21 points) were assessed. Higher scores indicated more severe fatigue. A CIS-Fatigue score ≥36 points was used to qualify patients as having severe fatigue.
A total of 239 patients with polymerase chain reaction/computed tomography–confirmed COVID-19 completed the survey 10 weeks (SD 2) and 23 weeks (SD 2) after onset of infectious symptoms, respectively (T1 and T2). Of these 239 patients, 198 (82.8%) were women; 142 (59.4%) had no self-reported pre-existing comorbidities; 208 (87%) self-reported being in good health before contracting COVID-19; and 62 (25.9%) were hospitalized during acute infection. The median age was 50 years (IQR 39-56). The vast majority of patients had severe fatigue at T1 and T2 (n=204, 85.4%, and n=188, 78.7%, respectively). No significant differences were found in the prevalence of normal, mild, and severe fatigue between T1 and T2 (
Fatigue in members of online long COVID support groups with a confirmed COVID-19 diagnosis decreases from 10 to 23 weeks after onset of symptoms. Despite this, severe fatigue remains highly prevalent. Both physical and mental fatigue are present. It remains unclear whether and to what extent fatigue will resolve spontaneously in the longer term.
Netherlands Trial Register NTR8705; https://www.trialregister.nl/trial/8705.
As the current COVID-19 pandemic continues to evolve, its impact becomes apparent. Clinical studies of hospitalized, laboratory-confirmed patients have shown that the acute phase of COVID-19 is characterized by a large array of respiratory and non-respiratory symptoms [
Fatigue, defined as “a subjective, unpleasant symptom which incorporates total body feelings ranging from tiredness to exhaustion creating an unrelenting overall condition which interferes with individuals’ ability to function to their normal capacity” [
To date, longitudinal studies that examine fatigue intensity in patients with long COVID are lacking. Moreover, it is not known whether patients experience mostly mental or physical fatigue during and after the infection. Therefore, the objectives of this study were to (1) assess the severity of fatigue over time in members of online long COVID peer support groups; and (2) assess whether members of online long COVID peer support groups experience mental fatigue, physical fatigue, or both. We hypothesized that fatigue would be common and persistent and that both physical and mental fatigue would be present in patients with long COVID.
This study is a prospective web-based survey of members of two Facebook peer support groups for patients with long COVID in the Netherlands (approximately 11,000 members; [
The survey was developed in close collaboration with scientists, methodologists, health care professionals and COVID-19 patients from the long COVID peer support groups (the Netherlands and Flanders). It was digitalized by ASolutions [
Respondents received questions regarding demographical aspects such as gender, age, weight, height, educational level (low/medium/high; classification according to the International Standard Classification of Education 2011 [
Information regarding received health care (yes/no) by a medical professional (eg, medical specialist; general practitioner [GP]; nurse) or an allied health care professional (AHP; eg, physiotherapist [PT]; psychologist; occupational therapist [OT]; dietician; speech and language therapist) was recorded.
Fatigue, the primary outcome measure, was measured using a subscale of the Checklist Individual Strength (CIS). The Checklist Individual Strength–subscale subjective fatigue (CIS-Fatigue) is a standardized questionnaire [
A total of 3 self-constructed questions (all part of the CIS-Fatigue subscale) were used to evaluate physical fatigue (“
Data are presented as means and standard deviations, medians, and interquartile ranges or as frequencies and proportions, where appropriate. Differences over time were analyzed by a paired
In total, 2159 members of online long COVID peer support groups filled out the first survey, of which 220 were excluded for being in the acute phase of COVID-19 (n=14), ICU admission during the acute phase of COVID-19 (n=15), onset of symptoms before January 1, 2020 (n=8), and an incomplete first survey (n=183). From the 1939 patients who were included, 1556 consented to be approached for follow-up research, of which 1005 (64.6%) completed the second survey. Patients who did not respond to the second survey were younger and more often had a presumed COVID-19 diagnosis. Further details can be found in a previously published paper [
Patients with confirmed COVID-19 were mostly middle-aged women (median age 50.0 years, IQR 39.0-56.0; 198/239 women, 82.8%) with a BMI indicating slight overweight (median BMI 26.0 kg/m2, IQR 23.4-30.5), and they completed the first (T1) and second (T2) survey on average 10.4 weeks (SD 2.4) and 22.6 weeks (SD 2.4) after onset of symptoms. Approximately 1 out of 4 patients (62/239, 25.9%) was hospitalized during the acute phase of COVID-19. The majority of respondents had no self-reported comorbidities (142/239, 59.4%) and good self-reported health status before the infection (208/239, 87%). Moreover, at T1 and T2, a minority of respondents self-reported good health (22/239, 9.2%, and 40/239, 16.7%, respectively [
Characteristics of patients with confirmed COVID-19 (n=239).
Characteristic | Value | |
Women, n (%) | 198 (82.8) | |
Age (years), median (IQR) | 50.0 (39.0-56.0) | |
BMI (kg/m2), median (IQR) | 26.0 (23.4-30.5) | |
Time between onset of symptoms and T1a survey (weeks), mean (SD) | 10.4 (2.4) | |
Time between onset of symptoms and T2b survey (weeks), mean (SD) | 22.6 (2.4) | |
Married/living with partner, n (%) | 173 (72.4) | |
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Low | 6 (2.5) |
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Medium | 126 (52.7) |
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High | 107 (44.8) |
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None | 142 (59.4) |
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1 | 62 (25.9) |
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≥2 | 35 (14.6) |
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Good | 208 (87) |
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Moderate | 28 (11.7) |
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Poor | 3 (1.3) |
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Good | 22 (9.2) |
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Moderate | 156 (65.3) |
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Poor | 61 (25.5) |
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During acute infection | 15 (11-18) |
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At T1 | 6 (4-9) |
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At T2 | 6 (3-8) |
Hospitalized during acute infection, n (%) | 62 (25.9) |
aT1: time of completing the first survey.
bT2: time of completing the second survey.
During the first 10 weeks after the onset of symptoms, 2 out of 3 patients (157/239, 65.7%) received or sought care from at least one medical professional (GP: 139/239, 58.2%; medical specialist: 73/239, 30.5%; nurse: 18/239, 7.5%), whereas 1 out of 3 (90/239, 37.7%) received or sought care from at least one allied health care professional (PT: 76/239, 31.8%; psychologist: 27/239, 11.3%; OT: 7/239, 2.9%, dietician: 25/239, 10.5%; and speech and language therapist: 6/239, 2.5%). The cumulative proportion of patients who received care from a medical professional and allied health care professional at T2 respectively increased significantly to 81.2% (194/239; GP: 170/239, 71.1%; medical specialist: 131/239, 54.8%; nurse: 32/239, 13.4%; all
Fatigue-related measures and received health care in patients with confirmed COVID-19 at on average 10 weeks (T1) and 23 weeks (T2) after onset of symptoms (n=239).
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Value | |||||||||
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T1a | T2b | |||||
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General fatigue (points on CIS-Fatiguec scale), median (IQR) | 48 (42-53) | 46 (37-50) | <.001 | ||||||
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Severe fatigue, n (%) | 204 (85.4) | 188 (78.7) | .03 | ||||||
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Mental fatigue (points on self-constructed questions), median (IQR) | 15 (10-17) | 14 (10-17) | .52 | ||||||
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Physical fatigue (points on self-constructed questions), median (IQR) | 19 (16-20) | 18 (14-19) | <.001 | ||||||
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157 (65.7) | 194 (81.2) | <.001 | ||||||
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General practitioner | 139 (58.2) | 170 (71.1) | <.001 | |||||
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Medical specialist | 73 (30.5) | 131 (54.8) | <.001 | |||||
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Nurse | 18 (7.5) | 32 (13.4) | <.001 | |||||
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90 (37.7) | 164 (68.6) | <.001 | ||||||
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Physiotherapist | 76 (31.8) | 157 (65.7) | <.001 | |||||
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Psychologist | 27 (11.3) | 55 (23) | <.001 | |||||
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Occupational therapist | 7 (2.9) | 27 (11.3) | <.001 | |||||
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Dietician | 25 (10.5) | 51 (21.3) | <.001 | |||||
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Speech and language therapist | 6 (2.5) | 21 (8.8) | <.001 | |||||
Rehabilitation (in- or outpatient), n (%) | 10 (4.2) | 32 (13.4) | <.001 |
aT1: time of completing the first survey.
bT2: time of completing the second survey.
cCIS-Fatigue: Checklist Individual Strength–subscale subjective fatigue.
Patients with confirmed COVID-19 reported a median CIS-Fatigue score of 48 points (IQR 42-53) at T1. The majority (204/239, 85.4%) reported severe fatigue at approximately 3 months after the onset of COVID-19 symptoms. The median CIS-Fatigue score improved significantly between T1 and T2 (median change –2 points, IQR –7 to 3;
Prevalence and change in fatigue in patients with long COVID who have confirmed COVID-19, measured using the CIS-Fatigue scale at on average 10 (T1) and 23 (T2) weeks after onset of symptoms (n=239). The width of the lines is proportional to the flow rate. No significant change in the prevalence of normal (≤26 points), mild (27-35 points), or severe (≥36 points) fatigue was found between T1 and T2 (McNemar-Bowker test,
Patients with confirmed COVID-19 reported median physical and mental fatigue scores of 19 points (IQR 16-20) and 15 points (IQR 10-17) at T1. Between T1 and T2, a significant decrease was found in physical fatigue score (median change –1 point, IQR –3 to 0;
The distribution of patients with long COVID who have confirmed COVID-19 across the spectrum of self-constructed mental (left) and physical (right) fatigue at on average 10 (T1) and 23 (T2) weeks after onset of symptoms (n=239). Scores range from 3 to 21 points, and higher scores indicate higher levels of fatigue. T1: time of completing the first survey; T2: time of completing the second survey.
To the best of our knowledge, this is the first study to measure fatigue over time in members from online long COVID peer support groups with confirmed COVID-19 using a validated and standardized measurement with generic cutoff values to determine normal, mild, and severe fatigue. Our study indicates that severe fatigue is highly prevalent in patients with long COVID at approximately 3 and 6 months after the infection. Furthermore, our longitudinal follow-up data suggest that fatigue does not resolve over time in all patients, even if they receive health care. In addition, patients experience both physical and mental fatigue.
Fatigue is the most prominent symptom in patients with long COVID [
Fatigue is a complex and challenging symptom, as multiple factors can play a role in the initiation and maintenance of fatigue, as seen in other chronic diseases [
The current study has several limitations. First, the survey was only made available to members of online long COVID peer support groups. This probably caused selection bias, as it is reasonable to assume that patients with high symptom burden are more likely to become members of online long COVID peer support groups. Second, all results were collected using a web-based survey. Therefore, besides the self-reported symptoms, the patients’ height, body weight, and medical status before and during the infection were also based on self-report, which may have affected the internal validity of the current findings to some extent. Recently, the National Institute for Health and Care Excellence [
Severe fatigue is highly prevalent in members of online long COVID peer support groups both at approximately 3 and 6 months after onset of symptoms. As not enough time has passed since the start of the COVID-19 pandemic, it is unclear whether this fatigue will resolve spontaneously in the longer term. Future research needs to focus on the prognosis, possible causes, and treatment strategies for physical and mental fatigue in patients with long COVID.
Members of online long COVID peer support groups with presumed COVID-19 (n=766): characteristics, received health care, and fatigue-related measures.
Additional information regarding self-reported pre-existing comorbidities and symptoms during the acute phase of COVID-19 and at the moment of completing the surveys.
The Checklist Individual Strength–subscale subjective fatigue.
Self-constructed physical and mental fatigue based upon 3 items of the Checklist Individual Strength–subscale subjective fatigue.
Flowchart of participants’ inclusion.
Prevalence of normal, mild, and severe fatigue using the Checklist Individual Strength–subscale subjective fatigue at T1 and T2, the proportional flow, and the direction of change of fatigue stratified for type of diagnosis.
Checklist Individual Strength–subscale subjective fatigue
computed tomography
general practitioner
intensive care unit
Middle East respiratory syndrome
occupational therapist
polymerase chain reaction
physiotherapist
quality of life
severe acute respiratory syndrome
Strengthening the Reporting of Observational Studies in Epidemiology
time point of completing the first survey
time point of completing the second survey
The research team acknowledges the valuable input from the patient representatives to develop the survey, and the technical support by ASolutions’ Martijn Briejers and Oscar Wagemakers. The scientific work of YMJG is financially supported by Lung Foundation Netherlands grant 4.1.16.085, FVCM is financially supported by ZonMW (ERACoSysMed grant 90030355), and RM is financially supported by Lung Foundation Netherlands grant 5.1.18.232.
MAS reports grants from Netherlands Lung Foundation, AstraZeneca, Boehringer Ingelheim, and Stichting Astma Bestrijding, all outside the submitted work. FMEF reports grants and personal fees from AstraZeneca, personal fees from Boehringer Ingelheim, personal fees from Chiesi, personal fees from GlaxoSmithKline, grants and personal fees from Novartis, and personal fees from TEVA, outside the submitted work. RP reports personal fees from MEDtalk and Health Investment. DJAJ has received lecture fees from Chiesi and Boehringer Ingelheim in the last 3 years, which are unrelated to this paper. All other authors declare that they have no conflicts of interest. No financial support was received for the preparation of this manuscript.