The persistence of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) after SARS-CoV-2 infection: A systematic review and meta-analysis

Highlights:

  • SARS-CoV-2 can trigger Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.
  • 51% of Long COVID-19 patients have Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.
  • Long COVID-19 is a new name for an old disease.

Abstract:

Objectives: Long COVID-19 (LC) patients experience a number of chronic idiopathic symptoms that are highly similar to those of post-viral Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). We have therefore performed a systematic review and meta-analysis to determine the proportion of LC patients that satisfy ME/CFS diagnostic criteria.

Methods: Clinical studies published between January 2020 to May 2023 were identified using the PubMed, Web of Science, Embase and CINAHL databases. Publication inclusion/exclusion criteria were formulated using the global CoCoPop framework. Data were pooled using a random-effects model with a restricted maximum-likelihood estimator. Study quality was assessed using the Joanna Briggs Institute critical assessment tool.

Results: We identified 13 eligible studies that reported a total of 1,973 LC patients. Our meta-analysis indicated that 51% (95% CI, 42%-60%) of LC patients satisfied ME/CFS diagnostic criteria with fatigue, sleep disruption, and muscle/joint pain being the most common symptoms. Importantly, LC patients also experienced the ME/CFS hallmark symptom, post-exertional malaise.

Conclusions: Our study not only demonstrates that LC patients exhibit similar symptom clusters to ME/CFS, but that approximately half of LC patients satisfy a diagnosis of ME/CFS. Our findings suggest that current ME/CFS criteria could be adapted to the identification of a subset of LC patients that may facilitate the standardized diagnosis, management and the recruitment for clinical studies in the future.

Source: Ankush Dehlia, Mark A. Guthridge. The persistence of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) after SARS-CoV-2 infection: A systematic review and meta-analysis. Journal of Infection, 2024, 106297, ISSN 0163-4453, https://doi.org/10.1016/j.jinf.2024.106297.
https://www.sciencedirect.com/science/article/pii/S0163445324002317 (Full text)

Impact of COVID-19 on myalgic encephalomyelitis/chronic fatigue syndrome-like illness prevalence: A cross-sectional survey

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) can be triggered by infectious agents including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the impact of the coronavirus disease 2019 (COVID-19) pandemic on ME/CFS prevalence is not well characterized.

Methods: In this population-based cross-sectional study, we enrolled a stratified random sample of 9,825 adult participants in the Kaiser Permanente Northern California (KPNC) integrated health system from July to October 2022 to assess overall ME/CFS-like illness prevalence and the proportion that were identified following COVID-19 illness. We used medical record and survey data to estimate the prevalence of ME/CFS-like illness based on self-reported symptoms congruent with the 2015 Institute of Medicine ME/CFS criteria. History of COVID-19 was based on a positive SARS-CoV-2 nucleic acid amplification test or ICD-10 diagnosis code in the medical record, or self-report of prior COVID-19 on a survey.

Results: Of 2,745,374 adults in the eligible population, an estimated 45,892 (95% confidence interval [CI]: 32,869, 58,914) or 1.67% (CI 1.20%, 2.15%) had ME/CFS-like illness. Among those with ME/CFS-like illness, an estimated 14.12% (CI 3.64%, 24.6%) developed the illness after COVID-19. Among persons who had COVID-19, those with ME/CFS-like illness after COVID-19 were more likely to be unvaccinated and to have had COVID-19 before June 1, 2021. All persons with ME/CFS-like illness had significant impairment in physical, mental, emotional, social, and occupational functioning compared to persons without ME/CFS-like illness.

Conclusions: In a large, integrated health system, 1.67% of adults had ME/CFS-like illness and 14.12% of all persons with ME/CFS-like illness developed it after COVID-19. Though COVID-19 did not substantially increase ME/CFS-like illness in the KPNC population during the study time period, ME/CFS-like illness nevertheless affects a notable portion of this population and is consistent with estimates of ME/CFS prevalence in other populations. Additional attention is needed to improve awareness, diagnosis, and treatment of ME/CFS.

Source: Wood MS, Halmer N, Bertolli J, Amsden LB, Nugent JR, Lin JS, Rothrock G, Nadle J, Chai SJ, Cope JR, Champsi JH, Yang J, Unger ER, Skarbinski J; for STOP-ME/CFS and COVID-SELECT. Impact of COVID-19 on myalgic encephalomyelitis/chronic fatigue syndrome-like illness prevalence: A cross-sectional survey. PLoS One. 2024 Sep 18;19(9):e0309810. doi: 10.1371/journal.pone.0309810. PMID: 39292671; PMCID: PMC11410243. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11410243/ (Full text)

How Long is Long COVID? Evaluation of Long-Term Health Status in Individuals Discharged from a Specialist Community Long COVID Service

Abstract:

Background: Post COVID-19 syndrome or Long Covid (LC) is a novel fluctuating condition with a protracted course in some patients. Specialist LC services have been operational in the UK since 2020 and deal with a high caseload of patients. Aims: To evaluate long-term outcomes in patients discharged from a community-based LC specialist service.

Methods: A service evaluation study that included patients who were well engaged in the services [completed the standard Patient Reported Outcome Measures (PROMs) and received intervention from clinician(s)] and had been discharged for at least 3 months from the service. They consented to the study and completed standard PROMs: COVID-19 Yorkshire Rehabilitation Scale (C19-YRS), EQ-5D-5L, and National Institute for Health and Care Excellence (NICE) criteria for Myalgia Encephalomyelitis/ Chronic Fatigue Syndrome (ME/CFS).

Results: Out of 460 patients contacted, 112 (average of 37.6 months since infection and 9.8 months post-discharge) completed the PROMs. 90.2% patients continued to experience LC symptoms and disability and had not returned to their pre-COVID health status. The average EQ-5D-5L index score was 0.53 (SD 0.29) highlighting a significant disability and that LC had become a long-term condition (LTC) in majority of patients who responded to the survey. 43% patients met the criteria for suspected ME/CFS.

Conclusion: A proportion of LC patients develop Persistent Long Covid (PLC) consistent with a LTC and had a significant overlap with ME/CFS.

Source: Bodey, R.; Grimaldi, J.; Tait, H.; Godfrey, B.; Witton, S.; Sharda, J.; Tarrant, R.; Sivan, M. How Long is Long COVID? Evaluation of Long-Term Health Status in Individuals Discharged from a Specialist Community Long COVID Service. Preprints 2024, 2024090813. https://doi.org/10.20944/preprints202409.0813.v1 https://www.preprints.org/manuscript/202409.0813/v1 (Full text available as PDF file)

Long COVID Is Not a Functional Neurologic Disorder

Abstract:

Long COVID is a common sequela of SARS-CoV-2 infection. Data from numerous scientific studies indicate that long COVID involves a complex interaction between pathophysiological processes. Long COVID may involve the development of new diagnosable health conditions and exacerbation of pre-existing health conditions. However, despite this rapidly accumulating body of evidence regarding the pathobiology of long COVID, psychogenic and functional interpretations of the illness presentation continue to be endorsed by some healthcare professionals, creating confusion and inappropriate diagnostic and therapeutic pathways for people living with long COVID.

The purpose of this perspective is to present a clinical and scientific rationale for why long COVID should not be considered as a functional neurologic disorder. It will begin by discussing the parallel historical development of pathobiological and psychosomatic/sociogenic diagnostic constructs arising from a common root in neurasthenia, which has resulted in the collective understandings of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and functional neurologic disorder (FND), respectively. We will also review the case definition criteria for FND and the distinguishing clinical and neuroimaging findings in FND vs. long COVID.

We conclude that considering long COVID as FND is inappropriate based on differentiating pathophysiologic mechanisms and distinguishing clinical findings.

Source: Davenport TE, Blitshteyn S, Clague-Baker N, Davies-Payne D, Treisman GJ, Tyson SF. Long COVID Is Not a Functional Neurologic Disorder. J Pers Med. 2024 Jul 29;14(8):799. doi: 10.3390/jpm14080799. PMID: 39201991. https://www.mdpi.com/2075-4426/14/8/799 (Full text)

Designing and optimizing clinical trials for long COVID

Abstract:

Long COVID is a debilitating, multisystemic illness following a SARS-CoV-2 infection whose duration may be indefinite. Over four years into the pandemic, little knowledge has been generated from clinical trials. We analyzed the information available on ClinicalTrials.gov, and found that the rigor and focus of trials vary widely, and that the majority test non-pharmacological interventions with insufficient evidence.

We highlight promising trials underway, and encourage the proliferation of clinical trials for treating Long COVID and other infection-associated chronic conditions and illnesses (IACCIs). We recommend several guidelines for Long COVID trials: First, pharmaceutical trials with potentially curative, primary interventions should be prioritized, and both drug repurposing and new drug development should be pursued.

Second, study designs should be both rigorous and accessible, e.g., triple-blinded randomized trials that can be conducted remotely, without participants needing to leave their homes.

Third, studies should have multiple illness comparator cohorts for IACCIs such as myalgic encephalomyelitis (ME/CFS) and dysautonomia, and screen for the full spectrum of symptomatology and pathologies of these illnesses.

Fourth, studies should consider inclusion/exclusion criteria with an eye towards equity and breadth of representation, including participants of all races, ethnicities, and genders most impacted by COVID-19, and including all levels of illness severity.

Fifth, involving patient-researchers in all aspects of studies brings immensely valuable perspectives that will increase the impact of trials. We also encourage the development of efficient clinical trial designs including methods to study several therapies in parallel.

Source: Vogel JM, Pollack B, Spier E, McCorkell L, Jaudon TW, Fitzgerald M, Davis H, Cohen AK. Designing and optimizing clinical trials for long COVID. Life Sci. 2024 Aug 13;355:122970. doi: 10.1016/j.lfs.2024.122970. Epub ahead of print. PMID: 39142505. https://www.sciencedirect.com/science/article/pii/S0024320524005605 (Full text)

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome After SARS-CoV-2 Infection

Abstract:

Importance: Chronic symptoms reported following an infection with SARS-CoV-2, such as cognitive problems, overlap with symptoms included in the definition of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Objective: To evaluate the prevalence of ME/CFS-like illness subsequent to acute SARS-CoV-2 infection, changes in ME/CFS symptoms through 12 months of follow-up, and the association of ME/CFS symptoms with SARS-CoV-2 test results at the acute infection-like index illness.

Design, setting, and participants: This prospective, multisite, longitudinal cohort study (Innovative Support for Patients with SARS-CoV-2 Infections Registry [INSPIRE]) enrolled participants from December 11, 2020, to August 29, 2022. Participants were adults aged 18 to 64 years with acute symptoms suggestive of SARS-CoV-2 infection who received a US Food and Drug Administration-approved SARS-CoV-2 test at the time of illness and did not die or withdraw from the study by 3 months. Follow-up surveys were collected through February 28, 2023.

Exposure: COVID-19 status (positive vs negative) at enrollment.

Main outcome and measures: The main outcome was the weighted proportion of participants with ME/CFS-like illness based on the 2015 Institute of Medicine clinical case definition using self-reported symptoms.

Results: A total of 4378 participants were included in the study. Most were female (3226 [68.1%]). Mean (SD) age was 37.8 (11.8) years. The survey completion rates ranged from 38.7% (3613 of 4738 participants) to 76.3% (1835 of 4738) and decreased over time. The weighted proportion of participants identified with ME/CFS-like illness did not change significantly at 3 through 12 months of follow-up and was similar in the COVID-19-positive (range, 2.8%-3.7%) and COVID-19-negative (range, 3.1%-4.5%) groups. Adjusted analyses revealed no significant difference in the odds of ME/CFS-like illness at any time point between COVID-19-positive and COVID-19-negative individuals (marginal odds ratio range, 0.84 [95% CI, 0.42-1.67] to 1.18 [95% CI, 0.55-2.51]).

Conclusions and relevance: In this prospective cohort study, there was no evidence that the proportion of participants with ME/CFS-like illness differed between those infected with SARS-CoV-2 vs those without SARS-CoV-2 infection up to 12 months after infection. A 3% to 4% prevalence of ME/CFS-like illness after an acute infection-like index illness would impose a high societal burden given the millions of persons infected with SARS-CoV-2.

Source: Unger ER, Lin JS, Wisk LE, Yu H, L’Hommedieu M, Lavretsky H, Montoy JCC, Gottlieb MA, Rising KL, Gentile NL, Santangelo M, Venkatesh AK, Rodriguez RM, Hill MJ, Geyer RE, Kean ER, Saydah S, McDonald SA, Huebinger R, Idris AH, Dorney J, Hota B, Spatz ES, Stephens KA, Weinstein RA, Elmore JG; Innovative Support for Patients with SARS-CoV-2 Infections Registry (INSPIRE) Group. Myalgic Encephalomyelitis/Chronic Fatigue Syndrome After SARS-CoV-2 Infection. JAMA Netw Open. 2024 Jul 1;7(7):e2423555. doi: 10.1001/jamanetworkopen.2024.23555. PMID: 39046739; PMCID: PMC11270135. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11270135/ (Full text)

Illness presentation and quality of life in myalgic encephalomyelitis/chronic fatigue syndrome and post COVID-19 condition: a pilot Australian cross-sectional study

Abstract:

Purpose: Post COVID-19 Condition (PCC), being persistent COVID-19 symptoms, is reminiscent of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)-a chronic multi-systemic illness characterised by neurocognitive, autonomic, endocrinological and immunological disturbances. This novel cross-sectional investigation aims to: (1) compare symptoms among people with ME/CFS (pwME/CFS) and people with PCC (pwPCC) to inform developing PCC diagnostic criteria; and (2) compare health outcomes between patients and people without acute or chronic illness (controls) to highlight the illness burdens of ME/CFS and PCC.

Methods: Sociodemographic and health outcome data were collected from n = 61 pwME/CFS, n = 31 pwPCC and n = 54 controls via validated, self-administered questionnaires, including the 36-Item Short-Form Health Survey version 2 (SF-36v2) and World Health Organization Disability Assessment Schedule version 2.0 (WHODAS 2.0). PwME/CFS and pwPCC also provided self-reported severity and frequency of symptoms derived from the Canadian and International Consensus Criteria for ME/CFS and the World Health Organization case definition for PCC.

Results: Both illness cohorts similarly experienced key ME/CFS symptoms. Few differences in symptoms were observed, with memory disturbances, muscle weakness, lymphadenopathy and nausea more prevalent, light-headedness more severe, unrefreshed sleep more frequent, and heart palpitations less frequent among pwME/CFS (all p < 0.05). The ME/CFS and PCC participants’ SF-36v2 or WHODAS 2.0 scores were comparable (all p > 0.05); however, both cohorts returned significantly lower scores in all SF-36v2 and WHODAS 2.0 domains when compared with controls (all p < 0.001).

Conclusion: This Australian-first investigation demonstrates the congruent and debilitating nature of ME/CFS and PCC, thereby emphasising the need for multidisciplinary care to maximise patient health outcomes.

Source: Weigel B, Eaton-Fitch N, Thapaliya K, Marshall-Gradisnik S. Illness presentation and quality of life in myalgic encephalomyelitis/chronic fatigue syndrome and post COVID-19 condition: a pilot Australian cross-sectional study. Qual Life Res. 2024 Jul 3. doi: 10.1007/s11136-024-03710-3. Epub ahead of print. PMID: 38961009. https://link.springer.com/article/10.1007/s11136-024-03710-3 (Full text)

Flow Clotometry: Measuring Amyloid Microclots in ME/CFS, Long COVID, and Healthy Samples with Imaging Flow Cytometry

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) has received more attention since the characterization of Long COVID (LC), a condition somewhat similar in symptom presentation and, to some extent, pathophysiological mechanisms. A prominent feature of LC pathology is amyloid, fibrinolysis-resistant fibrin(ogen) fragments, termed microclots. Despite prior identification of microclots in ME/CFS, quantitative analysis has remained challenging due to the reliance on representative micrographs and software processing for estimations.

Addressing this gap, the present study uses a cell-free imaging flow cytometry approach, optimized for the quantitative analysis of Thioflavin T-stained microclots, to precisely measure microclot concentration and size distribution across ME/CFS, LC, and healthy cohorts. We refer to our cell-free flow cytometry technique for detecting microclots as ‘flow clotometry’.

We demonstrate significant microclot prevalence in ME/CFS and LC, with LC patients exhibiting the highest concentration (18- and 3-fold greater than the healthy and ME/CFS groups, respectively). This finding underscores a common pathology across both conditions, emphasizing a dysregulated coagulation system. Moreover, relating to microclot size distribution, the ME/CFS group exhibited a significantly higher prevalence across all area ranges when compared to the controls, but demonstrated a significant difference for only a single area range when compared to the LC group.

This suggests a partially overlapping microclot profile in ME/CFS relative to LC, despite the overall higher concentration in the latter. The present study paves the way for prospective clinical application that aims to efficiently detect, measure and treat microclots.

Source: Etheresia Pretorius, Massimo Nunes, Jan pretorius et al. Flow Clotometry: Measuring Amyloid Microclots in ME/CFS, Long COVID, and Healthy Samples with Imaging Flow Cytometry, 24 June 2024, PREPRINT (Version 1) available at Research Square [https://doi.org/10.21203/rs.3.rs-4507472/v1] https://www.researchsquare.com/article/rs-4507472/v1 (Full text)

Systems Modeling Reveals Shared Metabolic Dysregulation and Novel Therapeutic Treatments in ME/CFS and Long COVID

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Long COVID are complex, multisystemic conditions that pose ongoing challenges to healthcare professionals. Emerging research suggests that ME/CFS and Long COVID exhibit overlapping metabolic symptoms, indicating possible shared metabolic dysfunctions. This study aims to systematically explore these shared metabolic disturbances and their potential treatments.

Utilizing our novel metabolic modeling method, GPMM, we identified the key metabolic irregularities in patients with ME/CFS and Long COVID, notably the downregulation of the alanine and aspartate metabolism pathway, and the arginine and proline metabolism pathway.

Genome-wide knockout analyses indicated that supplementation with aspartate (ASP) or asparagine (ASN) could potentially ameliorate these metabolic deficiencies. Further metabolic assessments in Long COVID patients highlighted the significant downregulation of ASP in both blood and muscle, supporting our predictions.

Consequently, we propose that the combination of l-ornithine and l-aspartate (LOLA) offers a promising approach to alleviate metabolic symptoms in both ME/CFS and Long COVID patients. This study not only elucidates the shared metabolic pathways in ME/CFS and Long COVID but also positions LOLA as a viable candidate for future clinical trials.

Source: Gong-Hua LiFeifei HanQing-Peng KongWenzhong Xiao. Systems Modeling Reveals Shared Metabolic Dysregulation and Novel Therapeutic Treatments in ME/CFS and Long COVID.

The risks of autoimmune- and inflammatory post-acute COVID-19 conditions: a network cohort study in six European countries, the US, and Korea

ABSTRACT

Objectives We aimed to assess the risk of autoimmune- and inflammatory post-acute COVID-19 conditions.

Design Descriptive network cohort study.

Setting Electronic health records from UK and Dutch primary care, Norwegian linked health registry, hospital records of specialist centres in Spain, France, and Korea, and healthcare claims from Estonia and the US.

Participants We followed individuals between September 2020 and the latest available data from the day they fulfilled at least 365 days of prior observation (general population), additionally from day 91 after a SARS-Cov-2 negative test (comparator) or a COVID-19 record (exposed patients).

Main outcome measures We assessed postural orthostatic tachycardia syndrome (POTS) diagnoses/symptoms, myalgic encephalomyelitis / chronic fatigues syndrome (ME/CFS) diagnoses/symptoms, multi-inflammatory syndrome (MIS), and several autoimmune diseases. For contextualisation, we assessed any diabetes mellitus (DM).

Meta-analysed crude incidence rate ratios (IRR) of outcomes measures after COVID-19 versus negative testing yield the ratios of absolute risks. Furthermore, incidence rates (IR) of the outcomes in the general population describe the total disease burden.

Results We included 34’549’575 individuals of whom 2’521’812 had COVID-19, and 4’233’145 a first negative test. After COVID-19 compared to test negative patients, we observed IRRs of 1.24 (1.23-1.25), 1.22 (1.21-1.23), and 1.12 (1.04-1.21) for POTS symptoms, ME/CFS symptoms and diagnoses, respectively. In contrast, autoimmune diseases and DM did not yield higher rates after COVID-19. In individual general database populations, IRs of POTS and ME/CFS diagnoses were 17-1’477/100’000 person-years (pys) and 2-473/100’000 pys, respectively. IRs of MIS were lowest with IRs 0.4-16/100’000 pys, those of DM as a benchmark 8-86/100’000 pys. IRs largely depended on the care setting.

Conclusion In our unmatched comparison, we observed that, following COVID-19, POTS and ME/CFS yielded higher rates than after negative testing. In absolute terms, we observed POTS and ME/CFS diagnoses to have a similar disease burden as DM.

WHAT IS ALREADY KNOWN ON THIS TOPIC

  • Observational research suggested positive associations between COVID-19 and so called post-acute COVID-19 conditions, whose spectrum is yet to be established

  • Basic research suggested pathways that link COVID-19 with autoimmune- and inflammatory diseases such as postural orthostatic tachycardia syndrome (POTS), myalgic encephalomyelitis / chronic fatigues syndrome (ME/CFS), multiple inflammatory syndrome (MIS), and autoimmune diseases

WHAT THIS STUDY ADDS

  • After COVID-19, the rates of POTS symptoms and ME/CFS symptoms/diagnoses was higher than those after negative testing

  • After COVID-19 versus negative testing, rates of ME/CFS diagnoses were increased in the working age group and rates of symptoms of POTS and ME/CFS were increased in children and elderly

  • Disease burdens of POTS and ME/CFS diagnoses in the general population were higher among women than among men and overall similar to that of diabetes mellitus

Source: Theresa Burkard, Kim López-Güell, Martí Català, Edward Burn, Antonella Delmestri, Sara Khalid, Annika M Joedicke, Daniel Dedman, Jessie O Oyinlola, Alicia Abellan, Laura Pérez-Crespo, Núria Mercadé-Besora, Talita Duarte-Salles, Daniel Prieto-Alhambra, Johnmary T Arinze, Mees Mosseveld, Raivo Kolde, Jaime Meléndez-Cardiel, Raúl López-Blasco, Álvaro Martínez, Bernardo Valdivieso, Dominique Delseny, Gregoire Mercier, Chungsoo Kim, Ji-woo Kim, Kristin Kostka, Juan Manuel Ramírez-Anguita, Miguel A Mayer, Nhung TH Trinh, Hedvig ME Nordeng, Roger Paredes, Anneli Uusküla, Akihiko Nishimura, Cora Loste, Lourdes Mateu, Junqing Xie. The risks of autoimmune- and inflammatory post-acute COVID-19 conditions: a network cohort study in six European countries, the US, and Korea. (Full text)