ME/CFS Evidence Browser — Classified Studies on Myalgic Encephalomyelitis

41–60 of 69 studies

E2 ModerateCohortPEM not requiredCross-Sectional

Long-Term Impairment of Working Ability in Subjects under 60 Years of Age Hospitalised for COVID-19 at 2 Years of Follow-Up: A Cross-Sectional Study.

Frallonardo, Luisa, Ritacco, Annunziata Ilenia, Amendolara, Angela et al.·Viruses·2024

This study followed 322 people under age 60 who were hospitalized with COVID-19 and checked on them about 2 years later. Researchers found that 42% of these patients reported difficulty working compared to before they got sick, even though they had recovered from the acute infection. The study identified that women, people with diabetes, and those who needed oxygen during hospitalization were more likely to have lasting work problems.

Long COVID Overlap

E2 ModerateCohortPEM not requiredCross-Sectional

Lowered oxygen saturation and increased body temperature in acute COVID-19 largely predict chronic fatigue syndrome and affective symptoms due to Long COVID: A precision nomothetic approach.

Al-Hadrawi, Dhurgham Shihab, Al-Rubaye, Haneen Tahseen, Almulla, Abbas F et al.·Acta neuropsychiatrica·2023

This study examined whether low oxygen levels and high fever during acute COVID-19 could predict who develops Long COVID symptoms like fatigue, depression, and anxiety. Researchers found that these two early warning signs, combined with being female, could explain about 61% of why some people develop these lingering symptoms. They also identified a subgroup (about 27% of Long COVID patients) with particularly severe oxygen drops and fever who experienced the worst combination of fatigue, mood problems, and digestive symptoms.

Long COVID Overlap

E2 ModerateCohortPEM not requiredLongitudinal

Three-Month Symptom Profiles Among Symptomatic Adults With Positive and Negative Severe Acute Respiratory Syndrome Coronavirus 2 Tests: A Prospective Cohort Study From the INSPIRE Group.

Spatz, Erica S, Gottlieb, Michael, Wisk, Lauren E et al.·Clinical infectious diseases : an official publication of the Infectious Diseases Society of America·2023

This study followed adults who tested positive or negative for COVID-19 and tracked their symptoms over three months. At the three-month mark, people who had COVID-19 were much more likely to still have symptoms like fatigue, breathing problems, or muscle pain compared to those who tested negative. Importantly, symptoms of post-infectious syndromes (like unrefreshing sleep and fatigue) were common in both groups, suggesting these symptoms can occur even without COVID-19 infection.

Long COVID Overlap

E2 ModerateCohortPEM unclearLongitudinal

Fatigue presentation, severity, and related outcomes in a prospective cohort following post-COVID-19 hospitalization in British Columbia, Canada.

Magel, Tianna, Meagher, Emily, Boulter, Travis et al.·Frontiers in medicine·2023

This study followed 88 people who were hospitalized with COVID-19 to see how many experienced long-lasting fatigue afterward. Two-thirds of patients had fatigue at 3 months, though this improved somewhat by 6 months, with about 60% still experiencing it. People who had more existing health conditions before COVID-19 were more likely to develop fatigue, suggesting that previous health status may influence recovery.

Long COVID Overlap

E2 ModerateCohortPEM unclearObservational

Post-Acute Sequelae of COVID-19 (PASC) in Pediatrics: Factors That Impact Symptom Severity and Referral to Treatment.

Soprano, Catherine M, Ngo, Ryan, Konys, Casey A et al.·Children (Basel, Switzerland)·2023

This study looked at how long COVID (called PASC) affects children and teenagers, comparing their experiences to adults. The researchers reviewed medical records to understand what symptoms young people had and whether they were referred to specialized treatment programs. The main finding was that young people with long COVID tend to have less severe symptoms than adults, though many young patients were not referred for treatment even when they needed it.

Long COVID Overlap

E2 ModerateCohortPEM requiredCross-Sectional

ME/CFS and Post-Exertional Malaise among Patients with Long COVID.

Jason, Leonard A, Dorri, Joseph A·Neurology international·2022

Researchers studied 465 people with long-term COVID symptoms to see how many also had ME/CFS (a serious condition causing extreme fatigue and worsening after activity). They found that about 6 in 10 people with long COVID met the medical criteria for ME/CFS. Interestingly, some people thought they had ME/CFS when they didn't, while others had ME/CFS without realizing it—showing that self-diagnosis alone isn't reliable.

Long COVID OverlapPost-Exertional Malaise

E2 ModerateCohortPEM not requiredObservational

Predictors of Long COVID in Patients without Comorbidities: Data from the Polish Long-COVID Cardiovascular (PoLoCOV-CVD) Study.

Chudzik, Michał, Lewek, Joanna, Kapusta, Joanna et al.·Journal of clinical medicine·2022

This study followed 488 people without serious health conditions after they recovered from COVID-19 to see who developed Long COVID symptoms. Researchers found that people who had a severe acute COVID-19 illness, higher body weight, and joint pain during their initial infection were more likely to develop Long COVID. About 45% of those who developed Long COVID had symptoms that persisted beyond the follow-up period.

Long COVID Overlap

E2 ModerateBehavioralPEM not requiredCross-Sectional

Prevalence and correlates of chronic fatigue syndrome and post-traumatic stress disorder after the outbreak of the COVID-19.

Simani, Leila, Ramezani, Mahtab, Darazam, Ilad Alavi et al.·Journal of neurovirology·2021

This study looked at whether people who survived COVID-19 developed chronic fatigue syndrome (ME/CFS) or PTSD within 6 months of infection. Among 120 COVID-19 survivors in Iran, about 2.5% met the criteria for ME/CFS and 5.8% showed signs of PTSD. Interestingly, the researchers found that having PTSD was not linked to developing ME/CFS in these patients.

Long COVID Overlap

E2 ModerateCohortPEM unclearObservational

Shadow Burden of Undiagnosed Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) on Society: Retrospective and Prospective-In Light of COVID-19.

Araja, Diana, Berkis, Uldis, Lunga, Asja et al.·Journal of clinical medicine·2021

This study examined how many people in Latvia may have ME/CFS symptoms but have never received a diagnosis, and investigated whether COVID-19 might cause similar long-term problems. Researchers compared symptom reports from diagnosed ME/CFS patients with undiagnosed people experiencing similar symptoms, and also tracked people who had recovered from COVID-19. The research found that undiagnosed patients face a significant financial burden on the healthcare system and themselves, and that COVID-19 can trigger ME/CFS-like symptoms in some people.

DiagnosticsLong COVID Overlap

E2 ModerateCohortPEM unclearCross-Sectional

Chronic fatigue syndrome: an emerging sequela in COVID-19 survivors?

Mantovani, Elisa, Mariotto, Sara, Gabbiani, Daniele et al.·Journal of neurovirology·2021

Some people who recover from COVID-19 continue to experience symptoms that look very similar to ME/CFS, including severe tiredness, pain, and difficulty thinking clearly. This study found that about 27% of COVID-19 survivors had these ME/CFS-like symptoms, and they reported worse sleep, more fatigue, and more difficulty with basic activities compared to those who recovered normally. The researchers measured markers of nerve damage and inflammation to understand what might be causing these symptoms.

Long COVID OverlapPost-Exertional Malaise

E2 ModerateCohortPEM unclearCross-Sectional

A Comprehensive Examination of Severely Ill ME/CFS Patients.

Chang, Chia-Jung, Hung, Li-Yuan, Kogelnik, Andreas M et al.·Healthcare (Basel, Switzerland)·2021

This study examined severely ill ME/CFS patients who are mostly housebound or bedbound—a group that hasn't received much research attention. Researchers found that fatigue, pain, and thinking difficulties were the most common complaints, and patients showed distinct sleep problems and hormone imbalances. The study suggests that ME/CFS and long COVID may share similar mechanisms, meaning treatments discovered for one condition could potentially help the other.

Long COVID OverlapPost-Exertional Malaise

E3 PreliminaryReviewPEM unclear

The lingering shadow of epidemics: post-acute sequelae across history.

Miller, Christine M, Moen, Janna K, Iwasaki, Akiko·Trends in immunology·2026

This review examines how infections throughout history have sometimes led to lasting illnesses similar to Long COVID, including conditions like ME/CFS. The authors show that post-infection syndromes have occurred for over 100 years after various infections (flu, EBV, Lyme disease, and others), suggesting this is not a new phenomenon. They argue that modern tools and technology now give us a better opportunity to understand why some infections trigger these chronic conditions.

Long COVID Overlap

E3 PreliminaryReviewPEM unclearReview-Narrative

Gulf War Illness: A Historical Review and Considerations of a Post-Viral Syndrome.

Bast, Elizabeth, Jester, Dylan J, Palacio, Ana et al.·Military medicine·2026

Gulf War Illness (GWI) is a chronic condition affecting 30-40% of veterans deployed during the 1990-1991 Gulf War, causing fatigue, pain, memory problems, digestive issues, and other symptoms similar to ME/CFS and long COVID. This review examines whether GWI might be caused by a viral infection, similar to how long COVID develops after SARS-CoV-2 infection. The authors suggest that veterans may have been exposed to a coronavirus related to MERS during their deployment, and they call for more research to explore this possibility.

Long COVID Overlap

E3 PreliminaryCommentaryPEM unclearEditorial

Post-infective myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and post-COVID as two puzzling faces of the same medal. Recent insights.

Chirumbolo, Salvatore, Franzini, Marianno, Tirelli, Umberto·International immunopharmacology·2025

This editorial examines the similarities between ME/CFS (a long-term illness causing extreme fatigue and other symptoms) and post-COVID syndrome (long-term effects some people experience after COVID-19 infection). The authors suggest these two conditions may share common underlying biological mechanisms, even though they arise from different infections. Understanding these connections could help doctors better recognize and treat both conditions.

Long COVID Overlap

E3 PreliminaryReviewPEM unclearReview-Narrative

Mitochondrial Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Syed, Abu Mohammad, Karius, Alexander K, Ma, Jin et al.·Physiology (Bethesda, Md.)·2025

This review examines how mitochondria—the parts of cells that produce energy—may not be working properly in ME/CFS patients. The authors suggest that problems with energy production in cells could explain why people with ME/CFS feel severely exhausted after physical activity. They also note that similar energy problems appear in long COVID, which suggests both conditions may share a common underlying cause.

Severe MELong COVID OverlapPost-Exertional Malaise

E3 PreliminaryCommentaryPEM unclearEditorial

Long Covid in Year 5: Some Progress, Still Many Questions.

Meagher, Timothy·Journal of insurance medicine (New York, N.Y.)·2025

Five years after Long Covid was first recognized in 2020, researchers have made progress understanding the condition, but significant challenges remain. While most people's symptoms improve over time, scientists still haven't found reliable blood tests to diagnose it or effective treatments. Long Covid appears to share many similarities with ME/CFS, and the condition can develop or worsen after repeated COVID-19 infections.

Long COVID Overlap

E3 PreliminaryReviewPEM unclearReview-Narrative

Considerations for Long COVID Rehabilitation in Women.

Verduzco-Gutierrez, Monica, Fleming, Talya K, Azola, Alba M·Physical medicine and rehabilitation clinics of North America·2025

Long COVID is a condition where people experience ongoing symptoms weeks or months after a COVID-19 infection. This review examines how rehabilitation can help long COVID patients, with special attention to how women are affected differently. The authors emphasize that personalized treatment plans involving multiple types of therapy and healthcare teamwork are important for recovery.

Long COVID Overlap

E3 PreliminaryReviewPEM unclearReview-Narrative

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

Lofrano-Porto, Adriana, D'Isabel, Susanne, Smith, Denise L·Frontiers in medicine·2024

This article reviews what we know about long COVID fatigue, especially in firefighters and other public safety workers. The authors explain why fatigue after COVID is so hard to diagnose and treat, since patients often look healthy on the outside even though they feel extremely tired. They describe possible biological reasons for this fatigue and discuss why it matters for workers whose jobs require them to be physically and mentally alert.

DiagnosticsLong COVID Overlap

E3 PreliminaryReviewPEM unclearReview-Narrative

[Myalgic encephalomyelitis/chronic fatigue syndrome as a complication of COVID-19 post-acute syndrome in adults. Bibliographic Review].

Carrillo Uguña, Miguel Esteban, Orellana Romero, Paula Michelle·Vertex (Buenos Aires, Argentina)·2024

This review examines how some COVID-19 survivors develop symptoms very similar to ME/CFS weeks or months after their acute infection ends. The authors found that over 87% of COVID-19 patients still experience at least one symptom two months after infection, and some of these symptoms match what ME/CFS patients experience. The study suggests that COVID-19 may trigger ME/CFS-like illness in some adults, similar to how other infections have been linked to ME/CFS in the past.

Long COVID OverlapPost-Exertional Malaise

E3 PreliminaryGuidelinePEM unclearGuideline

Designing and optimizing clinical trials for long COVID.

Vogel, Julia Moore, Pollack, Beth, Spier, Ezra et al.·Life sciences·2024

This study looked at all the clinical trials being tested for Long COVID on a public database and found that most trials are not well-designed or testing treatments that have enough evidence to justify testing. The researchers recommend that future trials should test actual medications that might cure Long COVID, be able to run remotely so sick patients don't have to travel, compare Long COVID to similar illnesses like ME/CFS, include diverse patients of all backgrounds and illness levels, and involve patients as research partners.

Long COVID Overlap

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Long-Term Impairment of Working Ability in Subjects under 60 Years of Age Hospitalised for COVID-19 at 2 Years of Follow-Up: A Cross-Sectional Study.

Lowered oxygen saturation and increased body temperature in acute COVID-19 largely predict chronic fatigue syndrome and affective symptoms due to Long COVID: A precision nomothetic approach.

Three-Month Symptom Profiles Among Symptomatic Adults With Positive and Negative Severe Acute Respiratory Syndrome Coronavirus 2 Tests: A Prospective Cohort Study From the INSPIRE Group.

Fatigue presentation, severity, and related outcomes in a prospective cohort following post-COVID-19 hospitalization in British Columbia, Canada.

Post-Acute Sequelae of COVID-19 (PASC) in Pediatrics: Factors That Impact Symptom Severity and Referral to Treatment.

ME/CFS and Post-Exertional Malaise among Patients with Long COVID.

Predictors of Long COVID in Patients without Comorbidities: Data from the Polish Long-COVID Cardiovascular (PoLoCOV-CVD) Study.

Prevalence and correlates of chronic fatigue syndrome and post-traumatic stress disorder after the outbreak of the COVID-19.

Shadow Burden of Undiagnosed Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) on Society: Retrospective and Prospective-In Light of COVID-19.

Chronic fatigue syndrome: an emerging sequela in COVID-19 survivors?

A Comprehensive Examination of Severely Ill ME/CFS Patients.

The lingering shadow of epidemics: post-acute sequelae across history.

Gulf War Illness: A Historical Review and Considerations of a Post-Viral Syndrome.

Post-infective myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and post-COVID as two puzzling faces of the same medal. Recent insights.

Mitochondrial Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Long Covid in Year 5: Some Progress, Still Many Questions.

Considerations for Long COVID Rehabilitation in Women.

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

[Myalgic encephalomyelitis/chronic fatigue syndrome as a complication of COVID-19 post-acute syndrome in adults. Bibliographic Review].

Designing and optimizing clinical trials for long COVID.

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