ME/CFS Evidence Browser — Classified Studies on Myalgic Encephalomyelitis

1081–1100 of 6,188 studies

E2 ModerateCohortPEM unclearCross-Sectional

A Cross-Sectional Study of Symptom Prevalence, Frequency, Severity, and Impact of Long COVID in Scotland: Part I.

Mclaughlin, Marie, Cerexhe, Luke, Macdonald, Eilidh et al.·The American journal of medicine·2025

Researchers surveyed 253 people living with long COVID in Scotland to understand which symptoms are most common and how severe they are. The most frequent symptoms were post-exertional malaise (when activity makes symptoms worse), extreme tiredness, and thinking problems. The study found that people living in areas with more deprivation experienced more symptoms, but factors like vaccination status and age did not significantly affect symptom patterns.

Post-Exertional Malaise

E2 ModerateCohortPEM not requiredObservational

Age-Related Changes in the Clinical Picture of Long COVID.

Fain, Mindy J, Horne, Benjamin D, Horwitz, Leora I et al.·Journal of the American Geriatrics Society·2025

This study looked at how Long COVID symptoms change as people get older. Researchers compared people aged 18–39 with those aged 40–70+ who had recovered from COVID-19 infection at least 135 days earlier. They found that middle-aged adults (40–59) were more likely to have Long COVID than young adults, but surprisingly, adults aged 70+ were actually less likely to report it—and when they did, their symptoms looked different, with less fatigue, pain, and brain fog compared to younger people.

Post-Exertional Malaise

E2 ModerateBehavioralPEM not requiredLongitudinal

Risk factors for fatigue severity in the post-COVID-19 condition: A prospective controlled cohort study of nonhospitalised adolescents and young adults.

Selvakumar, Joel, Havdal, Lise Beier, Brodwall, Elias Myrstad et al.·Brain, behavior, & immunity - health·2025

This study followed young people (ages 12–25) who had COVID-19 to understand why some develop long-lasting fatigue while others recover well. Researchers found that how severe symptoms were in the first few weeks after infection—and psychological factors like loneliness and worry—were much stronger predictors of ongoing fatigue at 6 months than any blood test or physical measure. Surprisingly, whether someone actually had COVID-19 made only a small difference; other life circumstances and emotional stress mattered more.

E2 ModerateCohortPEM not requiredObservational

Replicated blood-based biomarkers for myalgic encephalomyelitis not explicable by inactivity.

Beentjes, Sjoerd Viktor, Miralles Méharon, Artur, Kaczmarczyk, Julia et al.·EMBO molecular medicine·2025

Researchers found multiple blood markers that distinguish ME/CFS patients from healthy people, including signs of inflammation, insulin problems, and liver issues. Importantly, these differences were NOT caused by patients being physically inactive—they are genuine biological changes related to the disease itself. While no single blood test can diagnose ME/CFS yet, these findings suggest that a combination of blood markers could eventually provide objective diagnosis.

Post-Exertional Malaise

E2 ModerateCohortPEM unclearCross-Sectional

Comparable Immune Alterations and Inflammatory Signatures in ME/CFS and Long COVID.

Petrov, Steliyan, Bozhkova, Martina, Ivanovska, Mariya et al.·Biomedicines·2025

This study compared immune system markers in people with ME/CFS and Long COVID to those of healthy individuals. Both patient groups showed similar immune problems: lower levels of protective immune cells and higher levels of inflammatory substances in their blood. The findings suggest that ME/CFS and Long COVID may involve very similar underlying immune dysfunction.

Immune SystemLong COVID Overlap

E2 ModerateCohortPEM unclearObservational

Immune Signatures in Post-Acute Sequelae of COVID-19 (PASC) and Myalgia/Chronic Fatigue Syndrome (ME/CFS): Insights from the Fecal Microbiome and Serum Cytokine Profiles.

Tobi, Martin, Chaudhari, Diptaraj, Ryan, Elizabeth P et al.·Biomolecules·2025

Researchers compared gut bacteria and immune molecules in the blood of people with long COVID and chronic fatigue syndrome. They found that people with these conditions have unusual patterns of gut bacteria and different levels of immune signaling molecules compared to healthy controls. These differences suggest the immune system and gut health may play a role in why some people develop long-lasting fatigue after infection.

Immune System

E2 ModerateCohortPEM not requiredCross-Sectional

The relationship between fatigue, sleep quality, and sleep deprivation.

Ayas, Fahriye Yonca, Özcebe, Lütfiye Hilal·Sleep & breathing = Schlaf & Atmung·2025

This study looked at how fatigue, sleep quality, and daytime sleepiness are connected in workplace employees. Researchers found that when people have poor sleep quality or don't sleep enough hours, they tend to experience more fatigue and daytime sleepiness—and these problems appear to affect each other in a cycle. The study suggests that addressing sleep problems may be important for reducing fatigue and improving workplace safety.

Sleep

E2 ModerateBehavioralPEM not requiredCross-Sectional

Network structure of functional somatic symptoms.

Litzenburger, Alexandra, Rothacher, Yannick, Hanusch, Kay-Uwe et al.·Journal of psychosomatic research·2025

This study looked at how symptoms cluster together in people with functional somatic syndromes (like ME/CFS, fibromyalgia, and others). Researchers surveyed over 3,000 young adults and used network analysis to map which symptoms tend to appear together. They found that fatigue and depression are particularly important symptoms that connect different symptom groups, and identified ten distinct clusters of related symptoms.

Pain and SensitizationCognitive Impairment

E2 ModerateCohortPEM not requiredCross-Sectional

Multiple voxel pattern analysis shows associations between chronic fatigue syndrome and cortical atrophy.

Wu, Kang, Zou, Yihuai, Li, Yuanyuan et al.·Frontiers in neuroscience·2025

Researchers used specialized brain imaging to compare 37 people with ME/CFS to 34 healthy people and found that certain areas of the brain's outer layer are thinner in patients with ME/CFS. These thinner areas were linked to how severe their fatigue, pain, and reduced quality of life were. The study suggests that ME/CFS may involve physical changes in brain structure that could help explain why patients experience such debilitating fatigue.

E2 ModerateCohortPEM not requiredLongitudinal

Decreased risk of chronic fatigue syndrome following influenza vaccine: a 20-year population-based retrospective study.

Chang, Hsun, Yao, Wei-Cheng, Yu, Teng-Shun et al.·Journal of translational medicine·2025

This study looked at whether getting the flu increases the risk of developing ME/CFS. Researchers tracked nearly 310,000 people who had the flu and compared them to a similar group who did not get the flu over 12 years. They found that people who had the flu were about 50% more likely to develop ME/CFS afterward, but people who received the flu vaccine had lower rates of developing ME/CFS.

E2 ModerateCohortPEM unclearCase-Control

Killer cell immunoglobulin-like receptor (KIR) alleles suggested to be associated with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Ramadan, Donia Jamal, Kichula, Katherine M, Tao, Sudan et al.·Brain, behavior, and immunity·2025

This study examined specific genetic variations in natural killer (NK) cells—immune cells that help fight infections—in people with ME/CFS compared to healthy people. Researchers found that certain genetic variants were more common in ME/CFS patients while others were less common, suggesting that differences in how NK cells are regulated may play a role in ME/CFS. This supports the idea that immune system dysfunction is involved in the condition.

Immune System

E2 ModerateCohortPEM unclearCross-Sectional

Mapping the complexity of ME/CFS: Evidence for abnormal energy metabolism, altered immune profile, and vascular dysfunction.

Heng, Benjamin, Gunasegaran, Bavani, Krishnamurthy, Shivani et al.·Cell reports. Medicine·2025

This study examined blood samples from ME/CFS patients and healthy people to understand what goes wrong in the body. Researchers found that immune cells in ME/CFS patients are struggling to make energy (ATP), the fuel that powers our cells. The immune system also showed signs of being immature or worn out, and blood proteins related to clotting and blood vessel problems were elevated, suggesting blood vessel dysfunction may contribute to ME/CFS symptoms.

BiomarkersImmune System

E2 ModerateCohortPEM requiredLongitudinal

Incidence and Prevalence of Post-COVID-19 Myalgic Encephalomyelitis: A Report from the Observational RECOVER-Adult Study.

Vernon, Suzanne D, Zheng, Tianyu, Do, Hyungrok et al.·Journal of general internal medicine·2025

This study tracked over 11,000 people who had COVID-19 and about 1,400 who didn't, following them for at least 6 months to see how many developed ME/CFS. Researchers found that people who had COVID-19 were nearly 5 times more likely to develop ME/CFS compared to people who never had COVID-19. About 4.5% of COVID-infected participants developed ME/CFS, compared to only 0.6% of uninfected people.

Post-Exertional Malaise

E2 ModerateCohortPEM unclearCase-Control

SMPDL3B a novel biomarker and therapeutic target in myalgic encephalomyelitis.

Rostami-Afshari, Bita, Elremaly, Wesam, Franco, Anita et al.·Journal of translational medicine·2025

Researchers identified a protein called SMPDL3B that appears to be elevated in people with ME/CFS and linked to symptom severity. This protein is found in the blood at higher levels in ME patients, particularly in women, and seems to be influenced by hormones and immune system dysfunction. The study also tested two existing diabetes medications (vildagliptin and saxagliptin) in the laboratory and found they could potentially help restore balance to this protein, suggesting a possible new treatment approach.

BiomarkersImmune System

E2 ModerateDiagnosticPEM unclearMethods-Paper

Reliability and validity of the German version of the DePaul Symptom Questionnaire Post-Exertional Malaise (DSQ-PEM).

Kuczyk, Charlotte, Nöhre, Mariel, Herrmann-Lingen, Christoph et al.·Frontiers in psychiatry·2025

Researchers tested a German-language questionnaire designed to measure post-exertional malaise (PEM)—the worsening of symptoms that happens after physical or mental activity in ME/CFS and long COVID. They found the questionnaire is reliable and accurately distinguishes between people with and without long COVID, making it a useful tool for German-speaking patients and doctors.

Post-Exertional Malaise

E2 ModerateCohortPEM requiredCross-Sectional

Fatigue, interoplastic and nociplastic distress in myalgic encephalomyelitis/chronic fatigue syndrome, Gulf War Illness, and chronic idiopathic fatigue.

Chen, Emily, Rudder, Tamera, Nwankwere, Charles et al.·Frontiers in neuroscience·2025

This study compared pain sensitivity and fatigue in people with ME/CFS, Gulf War Illness, and chronic fatigue to understand what causes their symptoms. Researchers found that people with ME/CFS and Gulf War Illness have increased pain sensitivity (measured by pressing on their skin), and their pain and internal body sensations are closely linked. However, pain sensitivity didn't strongly correlate with fatigue levels, suggesting that fatigue may involve different mechanisms than pain.

Post-Exertional Malaise

E2 ModerateCohortPEM requiredCross-Sectional

Wearable technology in the management of complex chronic illness: preliminary survey results on self-reported outcomes.

Sawyer, Abbey, Preston, Rory, Leeming, Harry et al.·Frontiers in digital health·2025

This study looked at whether a smartphone app with a wearable armband helps people with ME/CFS and Long COVID manage their energy and symptoms. Over 1,300 people with these conditions used the app and answered questions about whether it helped them. Most people who used the app for at least a month reported feeling like they better understood their energy limits and how to manage daily activities, though some improvements may have simply come from tracking their own experience over time.

Post-Exertional Malaise

E2 ModerateCohortPEM unclearLongitudinal

Long-COVID in children and their parents: A prospective cohort study.

Iijima, Hiroyuki, Funaki, Takanori, Kubota, Mitsuru·Pediatrics international : official journal of the Japan Pediatric Society·2025

This study followed Japanese children hospitalized with COVID-19 and their parents to see how many developed long-COVID symptoms. About 45% of children had lingering symptoms one month after infection, dropping to 23% by six months. The most common symptoms were cough, tiredness, and sleep problems, with sleep issues being most strongly linked to a reduced quality of life.

Sleep

E2 ModerateCohortPEM unclearCross-Sectional

Distinct white matter alteration patterns in post-infectious and gradual onset chronic fatigue syndrome revealed by diffusion MRI.

Yu, Qiang, Kwiatek, Richard A, Del Fante, Peter et al.·Scientific reports·2025

This study used advanced brain imaging to examine whether two types of ME/CFS—one that starts suddenly after an infection and one that develops gradually—show different patterns of damage in the brain's white matter (the nerve fibers that allow brain regions to communicate). Researchers found that these two types of ME/CFS do indeed show distinct patterns, suggesting they may involve different disease processes. This finding supports the idea that ME/CFS is not a single uniform condition but may require different approaches depending on how it started.

E2 ModerateBehavioralPEM not requiredCross-Sectional

Post-Traumatic Stress Disorder and Complex Post-Traumatic Stress Disorder in People with Long COVID, ME/CFS, and Controls.

Sanal-Hayes, Nilihan E M, Hayes, Lawrence D, Mclaughlin, Marie et al.·The American journal of medicine·2025

This study compared how often people with long COVID, ME/CFS, and healthy people experience trauma-related mental health conditions. Researchers found that people with long COVID had the highest rates of these conditions (38% combined), followed by people with ME/CFS (20%), while healthy people had none. Both long COVID and ME/CFS groups showed more trauma-related symptoms than controls across multiple measures.

← Previous Next 20 studies →

Or browse by topic

PEM Immune Neuro Metabolic Biomarkers Severe ME Long COVID Cognitive

Evidence Atlas

Evidence browser

A Cross-Sectional Study of Symptom Prevalence, Frequency, Severity, and Impact of Long COVID in Scotland: Part I.

Age-Related Changes in the Clinical Picture of Long COVID.

Risk factors for fatigue severity in the post-COVID-19 condition: A prospective controlled cohort study of nonhospitalised adolescents and young adults.

Replicated blood-based biomarkers for myalgic encephalomyelitis not explicable by inactivity.

Comparable Immune Alterations and Inflammatory Signatures in ME/CFS and Long COVID.

Immune Signatures in Post-Acute Sequelae of COVID-19 (PASC) and Myalgia/Chronic Fatigue Syndrome (ME/CFS): Insights from the Fecal Microbiome and Serum Cytokine Profiles.

The relationship between fatigue, sleep quality, and sleep deprivation.

Network structure of functional somatic symptoms.

Multiple voxel pattern analysis shows associations between chronic fatigue syndrome and cortical atrophy.

Decreased risk of chronic fatigue syndrome following influenza vaccine: a 20-year population-based retrospective study.

Killer cell immunoglobulin-like receptor (KIR) alleles suggested to be associated with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Mapping the complexity of ME/CFS: Evidence for abnormal energy metabolism, altered immune profile, and vascular dysfunction.

Incidence and Prevalence of Post-COVID-19 Myalgic Encephalomyelitis: A Report from the Observational RECOVER-Adult Study.

SMPDL3B a novel biomarker and therapeutic target in myalgic encephalomyelitis.

Reliability and validity of the German version of the DePaul Symptom Questionnaire Post-Exertional Malaise (DSQ-PEM).

Fatigue, interoplastic and nociplastic distress in myalgic encephalomyelitis/chronic fatigue syndrome, Gulf War Illness, and chronic idiopathic fatigue.

Wearable technology in the management of complex chronic illness: preliminary survey results on self-reported outcomes.

Long-COVID in children and their parents: A prospective cohort study.

Distinct white matter alteration patterns in post-infectious and gradual onset chronic fatigue syndrome revealed by diffusion MRI.

Post-Traumatic Stress Disorder and Complex Post-Traumatic Stress Disorder in People with Long COVID, ME/CFS, and Controls.

Curated Collections

Neuroinflammation Evidence

Metabolism & Mitochondria

Biomarkers

PEM-Specific Research