Developing a clinical-pathological framework of long COVID-related fatigue applied to public safety workers

Abstract:

In the wake of the COVID-19 pandemic, millions worldwide are still struggling with persistent or recurring symptoms known as long COVID. Fatigue is one of the most prevalent symptoms associated with long COVID, and for many it can be debilitating. Understanding the potential pathological processes that link fatigue to long COVID is critical to better guide treatment. Challenges with diagnosis and treatment are reviewed, recognizing that post-COVID fatigue does not always present with corroborating clinical evidence, a situation that is frustrating for both patients and healthcare providers.

Firefighters are a group of public safety workers who are particularly impacted by long COVID-related fatigue. Firefighters must be able to engage in strenuous physical activity and deal with demanding psychological situations, both of which may be difficult for those suffering from fatigue. Disruption in public safety worker health can potentially impact community welfare. This review creates a framework to explain the clinical-pathological features of fatigue resulting from long COVID, addresses diagnosis and treatment challenges, and explores the unique impact fatigue may pose for public safety workers and their organizations.

Source: Lofrano-Porto A, D’Isabel S, Smith DL. Developing a clinical-pathological framework of long COVID-related fatigue applied to public safety workers. Front Med (Lausanne). 2024 Jul 17;11:1387499. doi: 10.3389/fmed.2024.1387499. PMID: 39086937; PMCID: PMC11288841. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11288841/ (Full text)

Clinical and Diagnostic Features of Post-Acute COVID-19 Vaccination Syndrome (PACVS)

Abstract:

Post-acute COVID-19 vaccination syndrome (PACVS) is a chronic disease triggered by SARS-CoV-2 vaccination (estimated prevalence 0.02%). PACVS is discriminated from the normal post-vaccination state by altered receptor antibodies, most notably angiotensin II type 1 and alpha-2B adrenergic receptor antibodies. Here, we investigate the clinical phenotype using a study registry encompassing 191 PACVS-affected persons (159 females/32 males; median ages: 39/42 years).

Unbiased clustering (modified Jaccard index) of reported symptoms revealed a prevalent cross-cohort symptomatology of malaise and chronic fatigue (>80% of cases). Overlapping clusters of (i) peripheral nerve dysfunction, dysesthesia, motor weakness, pain, and vasomotor dysfunction; (ii) cardiovascular impairment; and (iii) cognitive impairment, headache, and visual and acoustic dysfunctions were also frequently represented.

Notable abnormalities of standard serum markers encompassing increased interleukins 6 and 8 (>80%), low free tri-iodine thyroxine (>80%), IgG subclass imbalances (>50%), impaired iron storage (>50%), and increased soluble neurofilament light chains (>30%) were not associated with specific symptoms.

Based on these data, 131/191 participants fit myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and simultaneously also several other established dysautonomia syndromes. Furthermore, 31/191 participants fit none of these syndromes. In conclusion, PACVS could either be an outlier of ME/CFS or a dysautonomia syndrome sui generis.

Source: Mundorf AK, Semmler A, Heidecke H, Schott M, Steffen F, Bittner S, Lackner KJ, Schulze-Bosse K, Pawlitzki M, Meuth SG, Klawonn F, Ruhrländer J, Boege F. Clinical and Diagnostic Features of Post-Acute COVID-19 Vaccination Syndrome (PACVS). Vaccines (Basel). 2024 Jul 18;12(7):790. doi: 10.3390/vaccines12070790. PMID: 39066428; PMCID: PMC11281408. Mundorf AK, Semmler A, Heidecke H, Schott M, Steffen F, Bittner S, Lackner KJ, Schulze-Bosse K, Pawlitzki M, Meuth SG, Klawonn F, Ruhrländer J, Boege F. Clinical and Diagnostic Features of Post-Acute COVID-19 Vaccination Syndrome (PACVS). Vaccines (Basel). 2024 Jul 18;12(7):790. doi: 10.3390/vaccines12070790. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11281408/ (Full text)

Plasma Neurofilament Light Chain: A Potential Biomarker for Neurological Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex disorder characterized by heterogeneous symptoms, which lack specific biomarkers for its diagnosis. This study aimed to investigate plasma neurofilament light chain (NfL) levels as a potential biomarker for ME/CFS and explore associations with cognitive, autonomic, and neuropathic symptoms.

Here, 67 ME/CFS patients and 43 healthy controls (HCs) underwent comprehensive assessments, including neuropsychological evaluation, autonomic nervous system (ANS) testing, and plasma NfL level analysis. ME/CFS patients exhibited significantly higher plasma NfL levels compared to HC (F = 4.30, p < 0.05). Correlations were observed between NfL levels and cognitive impairment, particularly in visuospatial perception (r = -0.42; p ≤ 0.001), verbal memory (r = -0.35, p ≤ 0.005), and visual memory (r = -0.26; p < 0.05) in ME/CFS. Additionally, higher NfL levels were associated with worsened autonomic dysfunction in these patients, specifically in parasympathetic function (F = 9.48, p ≤ 0.003).

In ME/CFS patients, NfL levels explained up to 17.2% of the results in cognitive tests. Unlike ME/CFS, in HC, NfL levels did not predict cognitive performance. Elevated plasma NfL levels in ME/CFS patients reflect neuroaxonal damage, contributing to cognitive dysfunction and autonomic impairment.

These findings support the potential role of NfL as a biomarker for neurological dysfunction in ME/CFS. Further research is warranted to elucidate underlying mechanisms and clinical implications.

Source: Azcue N, Tijero-Merino B, Acera M, Pérez-Garay R, Fernández-Valle T, Ayo-Mentxakatorre N, Ruiz-López M, Lafuente JV, Gómez Esteban JC, Del Pino R. Plasma Neurofilament Light Chain: A Potential Biomarker for Neurological Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Biomedicines. 2024 Jul 11;12(7):1539. doi: 10.3390/biomedicines12071539. PMID: 39062112; PMCID: PMC11274366. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11274366/ (Full text)

Widespread Myalgia and Chronic Fatigue: Phagocytes from Macrophagic Myofasciitis Patients Exposed to Aluminum Oxyhydroxide-Adjuvanted Vaccine Exhibit Specific Inflammatory, Autophagic, and Mitochondrial Responses

Abstract:

(1) Background: Macrophagic myofasciitis (MMF) is an inflammatory histopathological lesion demonstrating long-term biopersistence of vaccine-derived aluminum adjuvants within muscular phagocytic cells. Affected patients suffer from widespread myalgia and severe fatigue consistent with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), a poorly understood disorder suspected to result from chronic immune stimulation by infectious and inorganic particles.

(2) Methods: In this study we determined the immuno-metabolic properties of MMF phagocytic cells compared to controls, at rest and upon exposure to aluminum oxyhydroxide adjuvant, with or without adsorbed antigens, using protein quantification and an oxygen consumption assay.

(3) Results: MMF and control cells similarly internalized the adjuvant and vaccine but MMF cells specifically expressed Rubicon and Nox2, two molecules unique to the LC3-associated phagocytosis (LAP) machinery, a non-canonical autophagic pathway able to downregulate canonical autophagy. MMF cells exhibited an altered inflammatory secretome, producing more pain-inducing CXC chemokines and less TNF-α than controls, consistent with chronic myalgia and exhaustion of the immune system previously documented in ME/CFS. MMF cells exhibited mitochondrial metabolism dysfunction, with exacerbated reaction to adjuvanted vaccine, contrasting with limited spare respiratory capacity and marked proton leak weakening energy production.

(4) Conclusions: MMF phagocytes seemingly use LAP to handle aluminum oxyhydroxide vaccine particles, secrete pain-inducing molecules, and exhibit exacerbated metabolic reaction to the vaccine with limited capacity to respond to ongoing energetic requests.

Source: Masson JD, Badran G, Gherardi RK, Authier FJ, Crépeaux G. Widespread Myalgia and Chronic Fatigue: Phagocytes from Macrophagic Myofasciitis Patients Exposed to Aluminum Oxyhydroxide-Adjuvanted Vaccine Exhibit Specific Inflammatory, Autophagic, and Mitochondrial Responses. Toxics. 2024 Jul 4;12(7):491. doi: 10.3390/toxics12070491. PMID: 39058143. https://www.mdpi.com/2305-6304/12/7/491 (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)

Six-year follow-up of participants in two clinical trials of rituximab or cyclophosphamide in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Objectives: In this six-year follow-up study, we used patient-reported outcome measures (PROMs) to compare values at baseline, at 18 months, and at six-year follow up from the CycloME and the RituxME trials.

Methods: Based on the hypothesis that ME/CFS in a subgroup of patients is a variant of an autoimmune disease, we performed two clinical trials between 2014 and 2017. The RituxME trial was a randomized, double-blind and placebo-controlled phase III trial of 151 patients, assessing the B-cell depleting antibody rituximab. The CycloME trial was an open-label phase II trial of 40 patients using intravenous cyclophosphamide. Here we report six-year follow-up from both trials, using the Short Form 36 Physical Function (SF-36 PF) and DePaul short form (DSQ-SF) questionnaires.

Result: Of the patients available after six years, 75.7% of RituxME and 94.4% of CycloME patients participated. In the RituxME rituximab group, the mean SF-36 PF scores were 32.9 at baseline, 42.4 at 18 months and 45.5 at six years. In the placebo group, the mean SF-36 PF scores were 32.3 at baseline, 45.5 at 18 months and 43.1 at six years. In the CycloME trial, mean SF-36 PF increased from 35.4 at baseline to 54.4 at 18 months, and 56.7 at six years. At six-year follow-up, 44.1% of cyclophosphamide-, 27.6% of rituximab- and 20.4% of placebo-treated patients had an SF-36 PF ≥ 70, and further, 17.6%, 8.6% and 7.4% of the corresponding patient groups had an SF-36 PF ≥ 90, which is within normal range. In terms of worsening at six years, 5.9% of cyclophosphamide-treated, 10.3% of rituximab-, and 14.8% of placebo-treated patients had a drop in SF-36 PF of 20 points or more from baseline. There were no serious unexpected adverse reactions.

Conclusions: After six years, 44.1% of the cyclophosphamide group scored an SF-36 PF of at least 70, and 17.6% of at least 90, suggesting that cyclophosphamide in a subgroup may modulate the disease course in a beneficial way. However, cyclophosphamide carries toxicity concerns and should not be used for ME/CFS patients outside clinical trials. Rather, these data should encourage efforts to better understand the disease mechanisms and to search for targeted and less toxic immune modulatory treatment for this patient group.

Source: Rekeland IG, Sørland K, Neteland LL, Fosså A, Alme K, Risa K, Dahl O, Tronstad KJ, Mella O, Fluge Ø. Six-year follow-up of participants in two clinical trials of rituximab or cyclophosphamide in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. PLoS One. 2024 Jul 23;19(7):e0307484. doi: 10.1371/journal.pone.0307484. PMID: 39042627; PMCID: PMC11265720. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11265720/ (Full text)

Sleep and circadian rhythm alterations in myalgic encephalomyelitis/chronic fatigue syndrome and post-COVID fatigue syndrome and its association with cardiovascular risk factors: A prospective cohort study

Abstract:

This study aimed to investigate circadian rhythm manifestations in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) patients (including a subpopulation of long-COVID patients) and matched healthy controls while also exploring their association with cardiovascular health variables.

Thirty-one ME/CFS patients (75% females), 23 individuals diagnosed with post-COVID ME/CFS (56% females) and 31 matched healthy controls (68% females) were enrolled in this study. Demographic and clinical characteristics were assessed using validated self-reported outcome measures. Actigraphy data, collected over one week, were used to analyze the 24-h profiles of wrist temperature, motor activity, and sleep circadian variables in the study participants. Associations between lipid profile with endothelial dysfunction biomarkers (such as endothelin-1, ICAM-1 and VCAM-1) and with sleep and circadian variables were also studied.

No differences were found in these variables between the two group of patients. Patients showed lower activity and worse sleep quality than matched healthy controls, together with a worse lipid profile than controls, that was associated with disturbances in the circadian temperature rhythm. ICAM-1 levels were associated with plasma lipids in healthy controls, but not in patients, who showed higher levels of endothelin-1 and VCAM-1.

These findings suggest that lipid profiles in ME/CFS are linked to disrupted circadian rhythms and sleep patterns, likely due to endothelial dysfunction. Furthermore, they highlight the intricate relationship between sleep, circadian rhythms, and cardiovascular health in this condition.

Source: Zerón-Rugerio MF, Zaragozá MC, Domingo JC, Sanmartín-Sentañes R, Alegre-Martin J, Castro-Marrero J, Cambras T. Sleep and circadian rhythm alterations in myalgic encephalomyelitis/chronic fatigue syndrome and post-COVID fatigue syndrome and its association with cardiovascular risk factors: A prospective cohort study. Chronobiol Int. 2024 Jul 22:1-12. doi: 10.1080/07420528.2024.2380020. Epub ahead of print. PMID: 39037125. https://pubmed.ncbi.nlm.nih.gov/39037125/

Increased risk of chronic fatigue syndrome following pneumonia: A population-based Cohort study

Abstract:

Background: Chronic fatigue syndrome (CFS) has been linked to several conditions, including infections, immune system changes, or emotional stress. Our study aimed to assess the risk of CFS after a pneumonia diagnosis using data from National Health Insurance Research Database of Taiwan.

Methods: In this nested case-control study, we identified 2,000,000 adult patients from a nationwide population-based health insurance claims database spanning from January 1, 2000, to December 31, 2017. Each case diagnosed with a pathogenic infection was matched with a corresponding control using propensity scores. We excluded individuals under 20 years of age, those with a history of pathogenic infections before the index date, or those with more than one potential pathogen. To estimate hazard ratios (HR) and the adjusted hazard ratio (aHR) with their respective 95 % confidence intervals (CI), we applied univariable and multivariable Cox proportional hazard models. The multivariable analysis incorporated adjustments for age, sex, and comorbidity-related confounders.

Results: The relationship between infection and the subsequent risk of CFS was assessed using Cox proportional hazards regression analysis. The incidence density rates were 6.13 and 8.70 per 1000 person-years among the non-pulmonary infection and pulmonary infection populations, respectively (adjusted hazard ratio [HR] = 1.4, 95 % confidence interval [CI] 1.32-1.5). Patients infected with Pseudomonas, Klebsiella pneumoniae, Haemophilus influenzae, Streptococcus pneumoniae, and influenza virus exhibited a significantly higher risk of CFS than those without these pathogens (p < 0.05). Additionally, patients with pneumonia had a significantly increased risk of thromboembolism compare with control group (p < 0.05).

Source: Hsu HJ, Chang H, Lin CL, Yao WC, Hung CL, Pang SP, Kuo CF, Tsai SY. Increased risk of chronic fatigue syndrome following pneumonia: A population-based Cohort study. J Infect Public Health. 2024 Jul 14;17(8):102495. doi: 10.1016/j.jiph.2024.102495. Epub ahead of print. PMID: 39018725. https://www.sciencedirect.com/science/article/pii/S1876034124002296 (Full text)

Data-independent LC-MS/MS analysis of ME/CFS plasma reveals a dysregulated coagulation system, endothelial dysfunction, downregulation of complement machinery

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating chronic condition that is characterized by unresolved fatigue, post-exertion symptom exacerbation (PESE), cognitive dysfunction, orthostatic intolerance, and other symptoms. ME/CFS lacks established clinical biomarkers and requires further elucidation of disease mechanisms.

A growing number of studies demonstrate signs of hematological and cardiovascular pathology in ME/CFS cohorts, including hyperactivated platelets, endothelial dysfunction, vascular dysregulation, and anomalous clotting processes. To build on these findings, and to identify potential biomarkers that can be related to pathophysiology, we measured differences in protein expression in platelet-poor plasma (PPP) samples from 15 ME/CFS study participants and 10 controls not previously infected with SARS-CoV-2, using DIA LC-MS/MS.

We identified 24 proteins that are significantly increased in the ME/CFS group compared to the controls, and 21 proteins that are significantly downregulated. Proteins related to clotting processes – thrombospondin-1 (important in platelet activation), platelet factor 4, and protein S – were differentially expressed in the ME/CFS group, suggestive of a dysregulated coagulation system and abnormal endothelial function. Complement machinery was also significantly downregulated, including C9 which forms part of the membrane attack complex. Additionally, we identified a significant upregulation of lactotransferrin, protein S100-A9, and an immunoglobulin variant.

The findings from this experiment further implicate the coagulation and immune system in ME/CFS, and bring to attention the pathology of or imposed on the endothelium. This study highlights potential systems and proteins that require further research with regards to their contribution to the pathogenesis of ME/CFS, symptom manifestation, and biomarker potential, and also gives insight into the hematological and cardiovascular risk for ME/CFS individuals affected by diabetes mellitus.

Source: Nunes, M., Vlok, M., Proal, A. et al. Data-independent LC-MS/MS analysis of ME/CFS plasma reveals a dysregulated coagulation system, endothelial dysfunction, downregulation of complement machinery. Cardiovasc Diabetol 23, 254 (2024). https://doi.org/10.1186/s12933-024-02315-x https://cardiab.biomedcentral.com/articles/10.1186/s12933-024-02315-x (Full text)

Lower hair cortisol concentration in adolescent and young adult patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Q-Fever Fatigue Syndrome compared to controls

Abstract:

Background: In patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), momentary cortisol concentrations in blood, urine, and saliva are lower compared to healthy controls. Long-term cortisol concentration can be assessed through hair, but it is unclear whether these concentrations are also lower. Additionally, it is unknown if lower cortisol extends to other patients suffering from persistent fatigue and how hair cortisol concentration (HCC) relates to fatigue levels. Therefore, this study examines HCC in fatigued patients with ME/CFS, Q fever Fatigue Syndrome (QFS), Post-COVID-19 condition (PCC), and Juvenile Idiopathic Arthritis (JIA).

Methods: Adolescent and young adult patients with ME/CFS (n=12), QFS (n=20), PCC (n=8), JIA (n=19), and controls (n=57) were included. Patients participated in a randomized cross-over trial (RCT) targeting fatigue through lifestyle and dietary self-management strategies. HCC was measured pre-post RCT in patients and once in controls, quantified using a LC-MS/MS-based method. Fatigue severity was measured with the Checklist Individual Strength-8. HCC was compared between groups with ANOVAs. Relations between HCC, fatigue severity, and other variables were investigated using linear regression analyses.

Results: The ME/CFS (p=.009) and QFS (p=.047) groups had lower HCC compared to controls. Overall, HCC was negatively associated with the presence of symptoms related to chronic fatigue syndromes (e.g., sleeping issues, often feeling tired, trouble thinking clearly; β=-0.018, p=.035), except in the QFS group (β=.063, p<.001). Baseline HCC did not predict fatigue improvement during the RCT (p=.449), and HCC increased during the trial (Mdif=.076, p=.021) regardless of clinically relevant fatigue improvement (p=.658).

Conclusion: Lower cortisol concentration can also be observed in the long-term. Lower HCC is not limited to ME/CFS, as it was also observed in QFS. The role of cortisol may differ between these diagnoses and appears to be unrelated to fatigue levels.

Source: Vroegindeweij A, Eijkelkamp N, van den Berg SAA, van de Putte EM, Wulffraat NM, Swart JF, Nijhof SL. Lower hair cortisol concentration in adolescent and young adult patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Q-Fever Fatigue Syndrome compared to controls. Psychoneuroendocrinology. 2024 Jun 28;168:107117. doi: 10.1016/j.psyneuen.2024.107117. Epub ahead of print. PMID: 38986244. https://pubmed.ncbi.nlm.nih.gov/38986244/