ME/CFS Evidence Browser — Classified Studies on Myalgic Encephalomyelitis

1081–1100 of 6,157 studies

E2 ModerateCohortPEM unclearCross-Sectional

Brain-targeted autoimmunity is strongly associated with Long COVID and its chronic fatigue syndrome as well as its affective symptoms.

Almulla, Abbas F, Maes, Michael, Zhou, Bo et al.·Journal of advanced research·2025

This study found that people with Long COVID have unusual immune responses targeting the brain and nerve cells. Researchers measured antibodies (immune proteins) in people with Long COVID and healthy controls, discovering that Long COVID patients have significantly higher levels of antibodies attacking several brain proteins. These brain-targeted immune responses were strongly linked to fatigue severity and mood symptoms like depression and anxiety.

Neuroinflammation

E2 ModerateCohortPEM not requiredObservational

Identifying commonalities and differences between EHR representations of PASC and ME/CFS in the RECOVER EHR cohort.

Powers, John P, McIntee, Tomas J, Bhatia, Abhishek et al.·Communications medicine·2025

Researchers compared medical records from millions of patients to see how Long COVID (PASC) and ME/CFS are similar and different. They found that both conditions share common symptoms like fatigue, breathing difficulties, and trouble concentrating, but Long COVID tends to have more heart and lung problems, while ME/CFS more often involves pain and sleep issues. These similarities suggest that some treatment approaches might help both conditions.

Pain and SensitizationSleepCognitive Impairment

E2 ModerateCohortPEM unclearCase-Control

Epstein-Barr virus (EBV) reactivation in post COVID-19.

Shady, Eslam Farid Abu, Ghallab, Abdelhakim Fouad, Shaker, Doaa Abdullah et al.·Auris, nasus, larynx·2025

This study looked at whether a virus called Epstein-Barr virus (EBV) wakes up again in people who have prolonged COVID symptoms like fatigue. Researchers compared 140 people with ongoing COVID fatigue to 80 people who fully recovered from COVID. They found that EBV was reactivated in about 29% of people with persistent fatigue compared to 11% of those who recovered, suggesting EBV reactivation might play a role in long COVID.

Immune SystemPost-Exertional Malaise

E2 ModerateCohortPEM not requiredCase-Control

Persistent symptoms and clinical findings in adults with post-acute sequelae of COVID-19/post-COVID-19 syndrome in the second year after acute infection: A population-based, nested case-control study.

Peter, Raphael S, Nieters, Alexandra, Göpel, Siri et al.·PLoS medicine·2025

This study followed nearly 1,000 people who had long-term COVID symptoms for over a year to see who improved and who stayed sick. Researchers found that about two-thirds of patients still had symptoms in the second year after infection, with fatigue, breathing problems, and thinking difficulties being the most common complaints. People who got better tended to have had milder initial infections and were more educated, while those who stayed sick were more likely to be overweight and have had specialist medical care or rehabilitation.

Post-Exertional Malaise

E2 ModerateCohortPEM unclearCross-Sectional

Health outcomes one year after Omicron infection among 12,789 adults: a community-based cross-sectional study.

Zhang, Hui, Yang, Peng, Gu, Xiaoying et al.·The Lancet regional health. Western Pacific·2025

This study followed over 12,000 people in Beijing who had COVID-19 (Omicron variant) about one year earlier. Researchers found that roughly 8% still had long COVID symptoms, with fatigue and post-exertional malaise (feeling worse after activity) being the most common complaints. People who had been reinfected with COVID were at much higher risk of developing long COVID.

Post-Exertional Malaise

E2 ModerateCohortPEM not requiredCase-Control

Affective and chronic fatigue symptoms are associated with serum neuronal damage markers in Parkinson's disease.

Al-Hakeim, Hussein Kadhem, Khudhair, Hayder Naji, Ranaei-Siadat, Sayed-Omid et al.·Scientific reports·2025

This study looked at people with Parkinson's disease who also experienced depression and extreme fatigue, similar to ME/CFS. Researchers found that certain proteins in the blood that signal brain cell damage were elevated in these patients, and these proteins were connected to inflammation, blood sugar problems, and the mood and fatigue symptoms they experienced.

NeuroinflammationImmune System

E2 ModerateCohortPEM not requiredCross-Sectional

The impact of APOE4 on neurological symptoms after exposure to K. brevis neurotoxin.

Aldrich, Gregory J, Nkiliza, Aurore, Ferguson, Scott et al.·Environmental toxicology and pharmacology·2025

Researchers studied whether a genetic variant called APOE4 makes people more vulnerable to neurological problems from brevetoxins—toxic chemicals released by harmful algae blooms in coastal Florida waters. They found that people carrying the APOE4 gene variant reported more memory problems and fatigue during red tide events compared to those without this variant. This suggests that certain genetic factors may increase how vulnerable someone's brain is to environmental toxins.

Cognitive Impairment

E2 ModerateCohortPEM unclearCross-Sectional

Deoxygenation Trends and Their Multivariate Association with Self-Reported Fatigue in Post-COVID Syndrome.

Ladek, Anja-Maria, Lucio, Marianna, Weiß, Andreas et al.·Biomedicines·2025

This study looked at oxygen levels in the muscles of 100 people with long COVID and 50 healthy controls while they performed light exercise (squeezing a stress ball). The researchers used a special non-invasive scan called NIRS to measure this. People with long COVID, especially those with post-exertional malaise, showed abnormal oxygen patterns in their muscles compared to healthy people, and this was linked to their fatigue levels.

Post-Exertional Malaise

E2 ModerateCohortPEM unclearLongitudinal

Exploring DNA methylation, telomere length, mitochondrial DNA, and immune function in patients with Long-COVID.

Polli, Andrea, Godderis, Lode, Martens, Dries S et al.·BMC medicine·2025

This study followed 358 people who had COVID-19 to understand why some develop Long-COVID with symptoms like extreme fatigue, sleep problems, and post-exertional malaise (feeling much worse after activity). Researchers measured biological markers in blood and found that two factors—elevated troponin T (a heart protein) and shortened telomeres (the protective caps on DNA)—were most strongly linked to Long-COVID, particularly the fatigue cluster. The study shows that Long-COVID is not a single illness but has different symptom patterns, suggesting different underlying causes may be at play.

BiomarkersPost-Exertional Malaise

E2 ModerateCohortPEM unclearCross-Sectional

Brain and muscle chemistry in myalgic encephalitis/chronic fatigue syndrome (ME/CFS) and long COVID: a 7T magnetic resonance spectroscopy study.

Godlewska, Beata R, Sylvester, Amy L, Emir, Uzay E et al.·Molecular psychiatry·2025

Researchers used advanced brain scans to look at chemical differences in the brains and muscles of people with ME/CFS, long COVID, and healthy people. They found that people with ME/CFS had higher levels of lactate (a chemical related to energy use) in specific brain areas, suggesting their brains may be working harder to produce energy. People with long COVID showed different changes - lower levels of a chemical called choline in the brain. These findings suggest that ME/CFS and long COVID may have different underlying causes, even though they produce similar symptoms.

Post-Exertional Malaise

E2 ModerateCohortPEM unclearCross-Sectional

Blood parameters differentiate post COVID-19 condition from Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Fibromyalgia.

Giménez-Orenga, Karen, Pierquin, Justine, Brunel, Joanna et al.·Brain, behavior, & immunity - health·2025

Researchers measured specific proteins and immune markers in the blood of people with post-COVID-19 condition, ME/CFS, and fibromyalgia to see if they could tell these conditions apart. They found that certain blood markers could distinguish post-COVID-19 condition from the other two conditions with very high accuracy, suggesting these illnesses may involve different immune patterns even though their symptoms overlap significantly.

Immune System

E2 ModerateCohortPEM unclearLongitudinal

AI-driven multi-omics modeling of myalgic encephalomyelitis/chronic fatigue syndrome.

Xiong, Ruoyun, Aiken, Elizabeth, Caldwell, Ryan et al.·Nature medicine·2025

Researchers used artificial intelligence to analyze blood, gut bacteria, immune cells, and symptoms from 249 ME/CFS patients tracked over 4 years. The AI model discovered that ME/CFS involves abnormal patterns in gut bacteria products, blood fats, and immune cells that attack infections—particularly special T cells that become overactive. These findings suggest ME/CFS isn't caused by a single problem but by multiple connected systems going wrong together.

BiomarkersGut MicrobiomeEnergy MetabolismImmune System

E2 ModerateCohortPEM unclearCross-Sectional

A patient-centered view of symptoms, functional impact, and priorities in post-COVID-19 syndrome: cross-sectional results from the Québec Action Post-COVID cohort.

Mayo, Nancy E, Brouillette, Marie-Josée, Falcone, Emilia Liana et al.·BMC infectious diseases·2025

This study surveyed 535 people in Quebec living with long-term COVID symptoms to understand what symptoms they experience, how much these symptoms affect their daily lives, and what treatments matter most to them. The most common symptom was fatigue, and people reported symptoms affecting multiple body systems. Most participants had been dealing with symptoms for over a year, and the impact on their quality of life was significant.

Post-Exertional Malaise

E2 ModerateBehavioralPEM not requiredCross-Sectional

Psychiatric Comorbidities in Fibromyalgia: A Comparison With Chronic Conditions and Healthy Controls.

Avni, Chen, Morr, Maya, Sinai, Dana et al.·The Journal of nervous and mental disease·2025

This study looked at how often mental health conditions like anxiety and depression occur in people with fibromyalgia compared to people with other long-term illnesses and healthy people. Researchers found that fibromyalgia patients had the highest rates of psychiatric conditions overall, with more than half experiencing anxiety and about half experiencing depression. The study suggests that treating fibromyalgia effectively requires addressing both the physical pain and mental health aspects together.

E2 ModerateCohortPEM unclearObservational

Assessing the influence of lived-experience experts on healthcare providers in a virtual community of practice: a qualitative study.

Weaver, Stephanie Sargent, Carry, Monique, Bertolli, Jeanne et al.·Frontiers in health services·2025

This study looked at whether having patients with lived experience of Long COVID and ME/CFS help teach doctors made a real difference in patient care. Researchers tracked what these patient-experts recommended to doctors through online training sessions from 2022-2024, and then asked actual patients if their doctors seemed to apply that advice. The main recommendations focused on validating patients' experiences, showing empathy, helping with referrals, and supporting self-care. Patients reported noticing positive changes in how their doctors treated them, suggesting that including patient-experts in medical education actually works.

Diagnostics

E2 ModerateCohortPEM unclearObservational

Chronicity rhetoric in health and welfare systems inhibits patient recovery: a qualitative, ethnographic study of fibromyalgia care.

Cupit, Caroline, Finlay, Teresa, Pope, Catherine et al.·Social science & medicine (1982)·2025

This study looked at how healthcare and welfare systems talk about fibromyalgia and similar long-term conditions like ME/CFS. Researchers found that when doctors and officials constantly describe these conditions as permanent and unchangeable ('chronicity rhetoric'), it can actually get in the way of patients healing and recovering. The study suggests that changing how we talk about these conditions—and how our support systems are designed—might help patients feel more hopeful and do better.

Diagnostics

E2 ModerateCohortPEM not requiredCross-Sectional

An Exploration of How Functional Neurological Disorder Is Discussed on X (Twitter): Mixed Methods Study Using Social Network and Content Analysis.

McLoughlin, Caoimhe, Wang, Jing-Yi, Do, Florence et al.·Journal of medical Internet research·2025

Researchers studied how people talk about Functional Neurological Disorder (FND) on social media platform X (Twitter). They found that most influential voices discussing FND actually dismiss or disagree with the condition, while people with ME/CFS and long COVID have more visibility in these conversations. This matters because online information shapes what patients and the public believe about these conditions.

E2 ModerateBehavioralPEM unclearObservational

Co-occurrence of severe fatigue and insomnia: implications for the outcome of cognitive behavioural therapies.

Rauwerda, Nynke L, Kuut, Tanja A, Braamse, Annemarie M J et al.·Behavioural and cognitive psychotherapy·2025

This study looked at whether having both severe fatigue and sleep problems at the same time affects how well cognitive behavioural therapy (CBT) works. Researchers found that CBT was equally effective whether patients had just fatigue, just insomnia, or both together. Interestingly, when one symptom improved during treatment, the other often improved too—but sometimes one symptom stayed even after the other got better.

Sleep

E2 ModerateCohortPEM unclearObservational

Elevated risk of new-onset chronic fatigue syndrome/myalgic encephalomyelitis up to four years after SARS-CoV-2 infection.

Hadidchi, Roham, Patel, Bhakti, Madan, Japji et al.·Journal of translational medicine·2025

This study found that people who had COVID-19 are more likely to develop ME/CFS in the years following infection compared to people who never had COVID-19. Women, and people with existing autoimmune or anxiety disorders, appear to be at higher risk. Importantly, having COVID-19 again did not increase the risk further, and blood tests during acute COVID were not able to predict who would later develop ME/CFS.

Long COVID Overlap

E2 ModerateCohortPEM not requiredCross-Sectional

The gut microbial composition is different in chronic fatigue syndrome than in healthy controls.

Prylińska-Jaśkowiak, Monika, Tabisz, Hanna, Kujawski, Sławomir et al.·Scientific reports·2025

Researchers compared the bacteria living in the gut of people with ME/CFS to healthy people and found clear differences. People with ME/CFS had less diverse bacterial communities and different types of bacteria overall. A computer program could accurately tell the difference between ME/CFS and healthy people just by looking at their gut bacteria patterns, suggesting this difference might be important for the illness.

Gut Microbiome

← Previous Next 20 studies →

Or browse by topic

PEM Immune Neuro Metabolic Biomarkers Severe ME Long COVID Cognitive

Evidence Atlas

Evidence browser

Brain-targeted autoimmunity is strongly associated with Long COVID and its chronic fatigue syndrome as well as its affective symptoms.

Identifying commonalities and differences between EHR representations of PASC and ME/CFS in the RECOVER EHR cohort.

Epstein-Barr virus (EBV) reactivation in post COVID-19.

Persistent symptoms and clinical findings in adults with post-acute sequelae of COVID-19/post-COVID-19 syndrome in the second year after acute infection: A population-based, nested case-control study.

Health outcomes one year after Omicron infection among 12,789 adults: a community-based cross-sectional study.

Affective and chronic fatigue symptoms are associated with serum neuronal damage markers in Parkinson's disease.

The impact of APOE4 on neurological symptoms after exposure to K. brevis neurotoxin.

Deoxygenation Trends and Their Multivariate Association with Self-Reported Fatigue in Post-COVID Syndrome.

Exploring DNA methylation, telomere length, mitochondrial DNA, and immune function in patients with Long-COVID.

Brain and muscle chemistry in myalgic encephalitis/chronic fatigue syndrome (ME/CFS) and long COVID: a 7T magnetic resonance spectroscopy study.

Blood parameters differentiate post COVID-19 condition from Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Fibromyalgia.

AI-driven multi-omics modeling of myalgic encephalomyelitis/chronic fatigue syndrome.

A patient-centered view of symptoms, functional impact, and priorities in post-COVID-19 syndrome: cross-sectional results from the Québec Action Post-COVID cohort.

Psychiatric Comorbidities in Fibromyalgia: A Comparison With Chronic Conditions and Healthy Controls.

Assessing the influence of lived-experience experts on healthcare providers in a virtual community of practice: a qualitative study.

Chronicity rhetoric in health and welfare systems inhibits patient recovery: a qualitative, ethnographic study of fibromyalgia care.

An Exploration of How Functional Neurological Disorder Is Discussed on X (Twitter): Mixed Methods Study Using Social Network and Content Analysis.

Co-occurrence of severe fatigue and insomnia: implications for the outcome of cognitive behavioural therapies.

Elevated risk of new-onset chronic fatigue syndrome/myalgic encephalomyelitis up to four years after SARS-CoV-2 infection.

The gut microbial composition is different in chronic fatigue syndrome than in healthy controls.

Curated Collections

Neuroinflammation Evidence

Metabolism & Mitochondria

Biomarkers

PEM-Specific Research