📜 First Historical Mentions
1934 – Los Angeles (USA)
An outbreak affects hospital staff. It was referred to as “atypical poliomyelitis.” Some medical historians consider this one of the earliest descriptions of Myalgic Encephalomyelitis (ME).
1955 – Royal Free Hospital (London, UK)
A large outbreak affects more than 200 hospital staff members.
Dr. Melvin Ramsay observes and describes this previously unknown disease, which he later calls “myalgic encephalomyelitis” (ME). This is the first official use of the term ME.
1950s–1960s
Similar outbreaks are described in Iceland, New Zealand, and the United States, reinforcing the idea of a distinct, often post-infectious disease.
🧾 Official Recognition
1969: The WHO lists Myalgic Encephalomyelitis (ME) in the International Classification of Diseases (ICD-10), code G93.3, as a neurological disorder.
Later, for clinical and research simplification, the term Chronic Fatigue Syndrome (CFS) appeared, especially in English-speaking countries.
Eventually, the dual designation ME/CFS was adopted to encompass both perspectives: Ramsay’s (neurological, post-infectious) and the broader “unexplained chronic fatigue” view.
👉 1955 (Ramsay, Royal Free Hospital) → first clear description and use of the term Myalgic Encephalomyelitis.
👉 1969 (WHO) → official international recognition as a neurological disorder.
🧾 ME/CFS Timeline Since 1969
1969 – WHO
The World Health Organization (WHO) lists Myalgic Encephalomyelitis (ME) in the International Classification of Diseases (ICD-10), code G93.3.
It is classified as a neurological disorder.
This is an official international recognition, even though the disease remains poorly understood.
1980s – Spread of the term “CFS”
In the USA, some doctors and institutions begin using the term Chronic Fatigue Syndrome (CFS).
This downplays the severity, obscures the neurological aspect, and creates lasting confusion between ME and CFS.
1994 – Fukuda Criteria (CDC, USA)
Define CFS as persistent fatigue for more than 6 months plus at least four symptoms (sleep disturbances, pain, cognitive issues, post-exertional malaise…).
Advantage: standardized diagnosis.
Limitation: criteria too broad → unclear diagnosis.
2001–2003 – Canadian Criteria
Emphasize post-exertional malaise as a cardinal symptom.
For the first time, the two terms ME/CFS are officially combined.
2011 – International Consensus Criteria
Remove the term “CFS” in favor of Myalgic Encephalomyelitis (ME).
Emphasis on immune and neurological abnormalities.
2015 – IOM Report (Institute of Medicine, USA)
Proposes the name SEID (Systemic Exertion Intolerance Disease).
Rarely adopted → too technical, adds to confusion.
2021 – ICD-11 (WHO)
ME/CFS remains a neurological disorder, now under code 8E49.
2020–2024 – Post-COVID and Biomarkers
The pandemic revitalizes research (Long COVID).
Studies on the microbiome, blood and neurological biomarkers, and clinical cohorts (e.g., Munich MUC-CFS).
✅ Today: ME/CFS is recognized as a severe neurological, often post-infectious disorder affecting millions worldwide (including ~2 million in France).
🔎 Why talk about epidemics if ME/CFS is not contagious?
- Historical outbreaks: collective clusters in hospitals (Royal Free 1955), Iceland, New Zealand, USA.
At the time, it was called “atypical poliomyelitis.” - Post-infectious hypothesis: ME/CFS is often triggered by infection (EBV, flu, SARS-CoV-2…), but an abnormal immune and neurological response develops.
- Why multiple cases in clusters?
During a viral outbreak, a whole group is exposed.
In genetically or immunologically predisposed individuals, the infection leaves sequelae → ME/CFS.
👉 In summary: the so-called “ME/CFS epidemics” were actually viral outbreaks that triggered several secondary cases of chronic post-infectious syndrome.