Tag: 2026

Risk factors for severe post-COVID condition in children, adolescents, and young adults

Abstract:

Post-COVID condition (PCC) in children and young people (CYP, PCCcyp) remains a significant health burden. Early identification of patients at risk for severe disease, including myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), is crucial for timely and adequate care. This monocentric, observational registry study, performed at a tertiary pediatric hospital in Germany, included CYP aged 7-25 years with PCCcyp at diagnosis. Standardized clinical assessment tools and patient-reported outcome measures were applied, including the novel Munich Long COVID Symptom Questionnaire (MLCSQ).

Severe PCC was defined by chronic symptom clusters, Fatigue Severity Scale (FSS), Total Composite Autonomic Symptom Score-31 (COMPASS-31), SF-36 composite scores, Bell Score, and confirmed ME/CFS diagnosis. Among 120 participants, severe PCCcyp was associated with a higher number of acute symptoms (ORadj 1.22, P < 0.001), acute orthostatic intolerance (ORadj 9.87, P = 0.002), acute trouble concentrating (ORadj 11.8, P = 0.005), and female sex (OR 3.31, P = 0.031).

Categorizing acute symptoms at a threshold of ≥ 12 yielded optimal model performance (AUC 0.857; sensitivity 65.6%; specificity 90.2%). ME/CFS was diagnosed in 24% of participants, all within the severe PCCcyp cluster, and was characterized by greater acute symptom complexity, more fatigue, more autonomic symptoms, and poorer function.

Conclusions: The number and pattern of acute symptoms during SARS-CoV-2 infection may serve as early, specific predictors of severe PCCcyp. Patients with ≥ 12 acute symptoms should be closely monitored to enable early diagnosis of severe PCCcyp and ME/CFS. A distinct cluster of severely affected patients, frequently with ME/CFS, was identified.

Trial registration: ClinicalTrials.gov: NCT05638724; Ethics approval (511/21, 2025-465-S-SB).

Source: Donath Q, Haegele M, Schindler D, Welzhofer T, Christa C, Grabbe A, Leone A, Ilhan C, Weidmann C, Eberhartinger M, Bechtold S, Bursch N, Wolf H, Hieber H, Peo LC, Bucka LA, Stojanov S, Warlitz C, Alberer M, Gerrer K, Hausruckinger A, Mittelstrass K, Wendtner CM, Hoechstetter MA, Grübl A, Toepfner N, Pricoco R, Scheibenbogen C, Mihatsch LL, Behrends U. Risk factors for severe post-COVID condition in children, adolescents, and young adults. Eur J Pediatr. 2026 May 4;185(5):344. doi: 10.1007/s00431-026-06995-3. PMID: 42082813. https://link.springer.com/article/10.1007/s00431-026-06995-3 (Full text available as PDF file)

Involvement of autoantibodies against G protein-coupled receptors in post-COVID condition and Chronic Fatigue Syndrome

Abstract:

Post-COVID condition (PCC) and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) are chronic disorders marked by fatigue, autonomic dysfunction, and cognitive impairment. Autoantibodies (AAbs) targeting adrenergic and muscarinic receptors have been implicated in their pathophysiology. This study aimed to investigate the association between these AAbs, autonomic nervous system (ANS) function, and cognitive performance in PCC and ME/CFS.

We included 96 PCC patients, 59 ME/CFS patients, and 36 healthy controls (HCs). Plasma AAbs against α1, β1, β2 adrenergic and M1-M4 muscarinic receptors were measured via ELISA. ANS function was evaluated using COMPASS-31, Sudoscan, hemodynamic tests (deep breathing, Valsalva, tilt test), and heart rate variability. Cognitive domains assessed included attention, fluency, processing speed, memory, visuoconstruction, perception, and executive functions.

ME/CFS patients had significantly higher β2 adrenergic AAb titers than PCC and HCs (F₂,₁₈₆ = 3.15, p = 0.046). PCC patients showed more borderline/pathological M3 muscarinic AAb results compared to HCs. β2 AAb levels correlated with increased autonomic symptoms in PCC (r = 0.27, p = 0.048) and sympathovagal imbalance in ME/CFS (r = 0.45, p = 0.001). In ME/CFS, M1, M3, and M4 AAb titers positively correlated with verbal and working memory performance.

Distinct AAb profiles in PCC and ME/CFS suggest potential differences in immunological mechanisms. β2 adrenergic receptor AAbs were associated with measures of autonomic dysfunction in PCC patients, and with sympathovagal parameters in ME/CFS patients. Muscarinic AAbs were correlated with cognitive performance in ME/CFS, supporting a potential role of these autoantibodies in autonomic and cognitive dysfunction. These findings support further investigation of AAbs as biomarkers and therapeutic targets.

Source: Azcue N, Prada A, Del Pino R, Acera M, Fernández-Valle T, Ayo-Mentxakatorre N, Pérez-Concha T, Murueta-Goyena A, Lafuente JV, López de Munain A, Ruiz Irastorza G, Ribacoba L, Gabilondo I, Tijero-Merino B, Gómez-Esteban JC. Involvement of autoantibodies against G protein-coupled receptors in post-COVID condition and Chronic Fatigue Syndrome. Sci Rep. 2026 May 5. doi: 10.1038/s41598-026-49131-9. Epub ahead of print. PMID: 42082542. https://www.nature.com/articles/s41598-026-49131-9 (Full text available as PDF file)

‘I Want Everyone to Have It, and Everyone to Be on It’: A Feasibility Study of the Transforming Long Covid Intervention

Abstract:

Background: An understanding of the nature of long Covid (LC) is evolving, with recent evidence highlighting the role of increased sympathetic activation and decreased parasympathetic response. Building upon this emerging science, the ‘Transforming Long COVID’ (TLC) programme was developed to support participants in their recovery by (i) introducing education on the neuroscience underpinning persistent symptoms (with a particular focus on the autonomic nervous system) and (ii) the development of self-management strategies to support recovery. The aim of this study was to examine the feasibility of the TLC programme with a cohort of people significantly affected by LC.

Methods: Seventeen participants took part in the 8-week TLC programme which comprised of seven content sessions and one discussion (Q&A) session. Participants completed survey scales (investigating anxiety, pain-related interference, pain catastrophising, sleep disturbance and fatigue) at baseline, immediately post-programme (at 8 weeks), and retention (at 13 weeks). Participants also took part in focus group interviews to investigate their experiences of the programme.

Results: Fourteen participants (82%) attended at least six of the seven TLC content sessions. Decreases in mean values over time were observed across all measures, indicating a positive (non-significant) change. Participants reported an increase in understanding of LC, new hope for recovery, belief that they now had a realistic pathway for recovery, validation of their experiences and symptoms, meaningful improvements in function, and enhanced ability to respond to and attenuate physical symptoms. No adverse events were reported. Participants highlighted a number of programme strengths, along with some potential areas for improvement.

Conclusion: The TLC programme was shown to be feasible based on engagement, adherence, acceptable completion of surveys, and no adverse events. Study findings point to the potential for this programme to be refined, trialled and evaluated with a larger sample.

Patient or public contribution: Four people (living with LC, ME/CFS, chronic migraine and chronic Lyme, fibromyalgia, and centralised pain syndrome), who have experience of applying a recovery approach aligned with the TLC programme, acted in a PPI (Public and Patient Involvement in research) capacity on this study. In addition, the lead author has personal experience with the illness, and developing the recovery approach, which helped inform programme structure and development [1]. These individuals provided advice and guidance on the potential structure for the group programme, course duration, tool selection, and language and wording of the programme and materials. Further detail is provided in the Supplementary Materials.

Source: Belton S, Goss H, Whyte E, McCaffrey N, Gibney S, Sheridan K. ‘I Want Everyone to Have It, and Everyone to Be on It’: A Feasibility Study of the Transforming Long Covid Intervention. Health Expect. 2026 Jun;29(3):e70681. doi: 10.1111/hex.70681. PMID: 42076812. https://onlinelibrary.wiley.com/doi/10.1111/hex.70681 (Full text)

Post-Exertional Malaise in Post-COVID-19 Syndrome: A Shift in the Frequency Across Pandemic Phases

Abstract:

Background: Post-exertional malaise (PEM), which is the cardinal feature of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), is also reported in a proportion of patients with post-COVID-19 syndrome (PCS). Our objective was to identify determinants that may be linked to the emergence of PEM in PCS patients.

Methods: Patients fulfilling the World Health Organization definition for PCS who attended the post-COVID unit of the Internal Medicine Department of Angers University Hospital, France, between June 2020 and December 2023 were included retrospectively. Their medical records were reviewed to extract information on COVID-19 infection history, characteristics of post-exertional malaise (PEM), fatigue severity, and relevant epidemiological variables.

Results: The study included 220 patients, grouped according to whether post-exertional malaise was present (PCS/PEM+) or absent (PCS/PEM-). PEM was observed in 26.4% of patients and was significantly linked to earlier COVID onset in 2020/2021 (OR 5.68 (95% CI: 1.66-19.45), p = 0.006), as well as higher fatigue levels (OR 2.07 (95% CI: 1.22-3.50), p = 0.007).

Conclusions: Patients who contracted COVID-19 during the pre-Omicron period reported PEM more frequently than those infected in later waves. This observation could reflect differences in viral characteristics following the emergence of the Omicron variant; however, alternative explanations-such as increasing vaccination coverage, accumulating post-infectious immunity, or other unmeasured factors-cannot be ruled out. Based on the observed link between PEM and symptom severity, PCS patients should be systematically assessed for the presence of PEM.

Source: Ghali A, Lavigne C, Ghali M, Lacombe V. Post-Exertional Malaise in Post-COVID-19 Syndrome: A Shift in the Frequency Across Pandemic Phases. J Clin Med. 2026 Apr 13;15(8):2948. doi: 10.3390/jcm15082948. PMID: 42074751. https://www.mdpi.com/2077-0383/15/8/2948 (Full text)

Improving Diagnostic Accuracy of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Through a Point-of-Care Clinical Algorithm

Abstract:

Despite the increasing prevalence and median severity of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), medical education on the disease is scant, leading to a diagnostic crisis in which the majority of people with ME/CFS are undiagnosed. We created a care process algorithm in AskMayoExpert accessible to all Mayo Clinic medical providers as a source for information on diagnosis and management of ME/CFS.

To evaluate whether the algorithm was associated with improved diagnostic accuracy, we compared concordance before versus after the algorithm was introduced, where concordance was defined as agreement between an appropriately coded referral to Mayo Clinic’s Chronic Fatigue Specialty Clinic and the specialty clinic with an expert diagnosis of ME/CFS.

Referrals to the Chronic Fatigue Specialty Clinic increased overall and were more likely to show concordance between specialist diagnosis and referral after the introduction of the ME/CFS AskMayoExpert algorithm. Particularly in diseases that are prevalent and poorly understood, a point-of-care clinical tool may offer just-in-time opportunities to improve diagnosis and management.

Source: Seltzer J, Grach SL, Eggers SD, Redetzke MM, Mau KJ, Chon TY, Ganesh R. Improving Diagnostic Accuracy of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Through a Point-of-Care Clinical Algorithm. Int J Environ Res Public Health. 2026 Apr 3;23(4):460. doi: 10.3390/ijerph23040460. PMID: 42074399. https://www.mdpi.com/1660-4601/23/4/460 (Full text)

Digital Approaches for Managing Brain Fog in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Interventions, Monitoring, and Future Directions

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a high-burden, under-researched condition characterized by heterogeneous and fluctuating symptoms, including cognitive dysfunction commonly described by patients as “brain fog”. Despite growing interest in digital health technologies for symptom monitoring and personalized care, their application to the assessment and management of cognitive dysfunction in ME/CFS remains unclear. This descriptive review aimed to examine the current scientific evidence on digital approaches related to brain fog in ME/CFS.

A structured literature search following PRISMA guidance was conducted to identify relevant studies. The available literature remains limited in scope and methodological maturity. During synthesizing across studies, three main functional domains of digital application become apparent: (1) digital tools for cognitive assessment, which have the strongest evidence base; (2) digital platforms for longitudinal monitoring; and (3) digitally mediated interventions or rehabilitation approaches, both of which are less well studied.

Simultaneously, the findings suggest that patient-reported brain fog may represent a visible component of the broader ME/CFS disease spectrum and could serve as an early clinical indicator guiding diagnosis and management. Interpreting these symptoms within a biopsychosocial framework may facilitate understanding of the complex nature of the disease and optimize the use of digital technologies for monitoring cognitive dysfunction and supporting patient-centered care in ME/CFS.

Source: Araja D, Murovska M, Krumina A, Eory A, Berkis U. Digital Approaches for Managing Brain Fog in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Interventions, Monitoring, and Future Directions. Life (Basel). 2026 Apr 1;16(4):571. doi: 10.3390/life16040571. PMID: 42073381. https://www.mdpi.com/2075-1729/16/4/571 (Full text)

3D Virtual Reality Performance Metrics as a Future Fatigue Biomarker in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating disorder, characterized by symptoms such as post-exertional malaise (PEM) and cognitive impairments. This study assessed reaction time (RT) metrics in three-dimensional (3D) visual tasks with the aim of objectively quantifying the cognitive impairments in ME/CFS patients compared to controls.

Methods: A total of 120 participants (60 ME/CFS patients and 60 controls) were recruited at the Department of Ophthalmology, Universität of Erlangen-Nürnberg. RT was assessed using a virtual reality-oculomotor test system, presenting 3D stimuli at three disparity levels (275″, 550″, and 1100″) within three gaming repetitions (R1, R2, and R3). Mixed-effects models were used to evaluate group differences, with age and gender as covariates. Pairwise contrasts were calculated to assess changes across repetitions. Fatigue self-assessments were recorded by validated questionnaires, (FACIT Fatigue Scale, Chalder Fatigue Scale, Bell Score and Health Assessment Questionnaire), and their correlation with RT metrics was portrayed using a Spearman correlation matrix.

Results: Estimated means (EM-means) for RT were significantly prolonged in ME/CFS patients compared to controls at disparity 275″ (1969 ms vs. 1384 ms; p = 0.0001), 550″ (1409 vs. 1071 ms; p = 0.0012) and 1100″ (1126 ms vs. 891 ms; p = 0.00223). Age was a significant covariate (p < 0.001), while gender showed no effect. Both groups demonstrated improvements in RT over repetitions; however, ME/CFS patients showed a significantly lower improvement compared to controls, reaching significance in R3 (p = 0.0042). RT metrics did not correlate with patients’ self-assessment scores.

Conclusions: ME/CFS patients showed consistently slower RTs compared to controls, particularly in later, easier gaming repetitions, potentially reflecting the impact of fatigue.

Source: Ladek AM, Priebe L, Harrer T, Harrer E, Michelson G, Knauer TS, Dias-Nunes DX, Mardin CY, Bergua A, Hohberger B. 3D Virtual Reality Performance Metrics as a Future Fatigue Biomarker in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). Biomedicines. 2026 Apr 9;14(4):855. doi: 10.3390/biomedicines14040855. PMID: 42072397. https://www.mdpi.com/2227-9059/14/4/855 (Full text)

 

Underuse of Pharmacologic Therapies for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Before Specialist Evaluation

Abstract:

Purpose: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a multisystem neurologic disease characterized by profound fatigue and decreased functional capacity, postexertional malaise, and unrefreshing sleep, along with cognitive impairment and/or orthostatic intolerance. Its prevalence has risen exponentially with the COVID-19 pandemic. Pharmacologic therapies have been used successfully by ME/CFS specialists but may be underused by the general medical field.

Methods: To assess this potential practice gap, we retrospectively analyzed the records of 571 patients with an ME/CFS diagnosis referred to our ME/CFS specialty clinic in Minnesota during 2018-2022. We ascertained medications that had already been tried at the time of consultation and also ascertained supplement use.

Results: With the exception of medications primarily used for pain and anxiety, use of pharmacotherapy for ME/CFS symptom management as proposed by specialists was limited. Overall, 68.3% of patients had had at least 1 medication potentially prescribed for ME/CFS; the most common were serotonin-norepinephrine reuptake inhibitors, gabapentin, and tricyclic antidepressants. A slightly larger share of patients, 72.2%, reported having taken at least 1 dietary supplement; the most common were vitamin D, vitamin B12 and B complex, and fish oil.

Conclusion: Our findings suggest that potentially helpful medications for ME/CFS are being underprescribed in the general medical field and that patients may resort to supplements to manage symptoms. Better education of clinicians about available treatment options and treatment guides may improve management of this debilitating disease.

Source: Grach SL, Seltzer J, Mueller MR, Aakre CA, Natividad LT, Lawson DK, Ganesh R, Hurt RT. Underuse of Pharmacologic Therapies for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Before Specialist Evaluation. Ann Fam Med. 2026 Apr 29:250266. doi: 10.1370/afm.250266. Epub ahead of print. PMID: 42055743. https://www.annfammed.org/content/early/2026/04/24/afm.250266-0 (Full text available as PDF file)

Symptom clusters in ME/CFS reflect distinct neuroimmune and autonomic pathophysiological mechanisms: a translational model

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating multisystem disease characterized by heterogeneous symptom patterns. Previous work suggested that specific symptoms tend to co‑occur, pointing toward underlying biological mechanisms. This study aimed to empirically validate literature‑based, hypothesis‑driven symptom clusters and assess whether they reflect distinct neuroimmune and autonomic pathophysiological pathways.

Methods: Symptom data from 748 adults with ME/CFS (≥20 years) participating in the APAV‑ME/CFS study were analyzed. Symptoms were assigned to predefined mechanistic groups informed by current pathophysiological hypotheses. Exploratory and Confirmatory Factor Analyses, followed by Structural Equation Modeling (SEM), evaluated the coherence, distinctiveness, and hierarchical structure of each cluster. Robustness was tested using a stratified, randomized training dataset.

Results: A coherent Brain factor (brain fog, sensory hypersensitivity, visual disturbances, sleep disturbances, headaches) showed excellent fit (RMSEA = 0.021; CFI = 0.996). Gastrointestinal symptoms demonstrated stronger internal consistency than Immune symptoms, and model comparisons supported a two‑factor Gut–Immune structure. Across all analyses, symptom groups emerged as internally consistent and statistically distinct. A higher‑order SEM including a common latent factor yielded excellent fit for the Autonomic symptom complex.

Conclusions: The findings support ME/CFS as a complex neuroimmune–autonomic multisystem disorder and suggest that symptom clusters align with functional biological systems. Mechanism-aligned symptom subgrouping may enable pathophysiology-guided diagnostics, patient stratification, and targeted therapeutic development. The proposed interpretations of underlying mechanisms derive from the integration of existing literature and were not directly measured in this study. The identified clusters therefore indicate mechanistic alignment rather than direct mechanistic validation.

Source: Habermann-Horstmeier L, Horstmeier LM. Symptom clusters in ME/CFS reflect distinct neuroimmune and autonomic pathophysiological mechanisms: a translational model. J Transl Med. 2026 Apr 28;24(1):606. doi: 10.1186/s12967-026-08159-1. PMID: 42050709; PMCID: PMC13126800. https://pmc.ncbi.nlm.nih.gov/articles/PMC13126800/ (Full text)

Regulatory Cycles of Orexin and Glucagon-Like Peptide-1 in Post-Viral Syndromes

Abstract:

Post-viral syndromes are heterogeneous multisystem diseases without a uniform etiology that occur as a result of acute viral infections. During the COVID-19 pandemic, the number of patients increased dramatically due to infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This is known as post-acute sequelae of COVID-19 (PASC), with many cases also meeting the criteria for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), the most severe form of a post-viral disease, characterized by severe fatigue, post-exertional malaise (PEM), unrefreshing sleep, neurocognitive impairment, and autonomic and immune dysregulation.

Orexin (OX) neuropeptides, which regulate arousal, metabolism, and neuroendocrine functions, may serve as a central link between stress, immune activation, and metabolic changes in these syndromes. Notable phenotypic similarities between OX system dysfunction and core features of PASC and ME/CFS, including fatigue, sleep issues, impaired glucose metabolism, and neuropsychiatric symptoms, support a mechanistic model in which impaired OX signaling contributes to post-viral endocrine and metabolic dysfunction.

This review examines the role of OX in regulating glucose metabolism, HPA axis activity, and systemic homeostasis, with a specific focus on sexually dimorphic expression and function in relation to post-viral syndromes. We also highlight the effect of glucagon-like peptide-1 (GLP-1), another key player in metabolism, which also has neuroprotective, anti-inflammatory, vasoprotective, and immunomodulatory effects. We further emphasize emerging therapeutic strategies, such as GLP-1 receptor agonists (GLP-1RAs) and drugs targeting the OX system.

Together, these insights provide an integrated framework for understanding and targeting the neuroendocrine-metabolic underpinnings of PASC, ME/CFS, and other post-viral syndromes.

Source: Ruhrländer J, Schieffer E, Schieffer B. Regulatory Cycles of Orexin and Glucagon-Like Peptide-1 in Post-Viral Syndromes. Endocr Rev. 2026 Apr 27:bnag009. doi: 10.1210/endrev/bnag009. Epub ahead of print. PMID: 42037238. https://pubmed.ncbi.nlm.nih.gov/42037238/