This study sought to ascertain the prevalence of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) among a sample of 465 patients with Long COVID. The participants completed three questionnaires: (1) a new questionnaire measuring both the frequency and severity of 38 common symptoms of COVID and Long COVID, (2) a validated short form questionnaire assessing ME/CFS, and (3) a validated questionnaire measuring post-exertional malaise. The population was predominantly white, female, and living in North America. The mean duration since the onset of COVID-19 symptoms was 70.5 weeks. Among the 465 participants, 58% met a ME/CFS case definition. Of respondents who reported that they had ME/CFS only 70.57% met criteria for ME/CFS and of those who did not report they had ME/CFS, 29.43% nevertheless did meet criteria for the disease: both over-diagnosis and under-diagnosis were evident on self-report. This study supports prior findings that ME/CFS occurs with high prevalence among those who have persistent COVID-19 symptoms.

An exploratory factor analysis (EFA) can provide a window into the latent dimensions of a disease, such as Long COVID. Discovering the latent factors of Long COVID  enables researchers and clinicians to better conceptualize, study and treat this disease. In this study, participants were recruited from social media sites dedicated to COVID and Long COVID. Among the 480 participants, those who completed at least 90% of the survey, reported symptoms for two or more months since COVID-19 symptom onset, and had not been hospitalized for COVID were used in the EFA. The mean duration since initial symptom onset was 74.0 (37.3) weeks. A new questionnaire called The DePaul Symptom Questionnaire-COVID was used to assess self-reports of the frequency and severity of 38 Long COVID symptoms experienced over the most recent month. The most burdensome symptoms were “Symptoms that get worse after physical or mental activities (also known as Post-Exertional Malaise),” “Fatigue/extreme tiredness,” “Difficulty thinking and/or concentrating,” “Sleep problems,” and “Muscle aches.” The EFA resulted in a three-factor model with factors labeled General, PEM/Fatigue/Cognitive Dysfunction, and Psychological, consisting of 16, 6, and 3 items respectively (25 items in total). The reliability of the items in the EFA was .90 using a split-half reliability test. Finally, participant self-reported level of functional impairment was analyzed across the three EFA factors. Interpretations and applications to research and practice are provided.

BACKGROUND: There is limited information on what acute factors predict more long-term symptoms from COVID-19. OBJECTIVE: Our objective was to conduct an exploratory factor analysis of self-reported symptoms at two time points of Long COVID-19. METHODS: Data from patients with Long COVID-19 were collected at the initial two weeks of contracting SARS CoV-2 and the most recent two weeks, with a mean duration of 21.7 weeks between the two-time points. At time point 2, participants also complete the Coronavirus Impact Scale (CIS), measuring how the COVID-19 pandemic affected various dimensions of their lives (e.g., routine, access to medical care, social/family support, etc.). RESULTS: At time 1, a three-factor model emerged consisting of Cognitive Dysfunction, Autonomic Dysfunction and Gastrointestinal Dysfunction. The analysis of time 2 resulted in a three-factor model consisting of cognitive dysfunction, autonomic dysfunction, and post-exertional malaise. Using factor scores from time 1, the Autonomic Dysfunction and the Gastrointestinal Dysfunction factor scores significantly predicted the CIS summary score at time two. In addition, the same two factor scores at time 1 predicted the occurrence of myalgic encephalomyelitis/chronic fatigue syndrome at time 2. CONCLUSION: As Cognitive and Autonomic Dysfunction emerged as factors for both time points, suggesting health care workers might want to pay particular attention to these factors that might be related to later symptoms and difficulties with returning to pre-illness family life and work functioning.