Britannica updated their information on ME/CFS in February 2025. Britannica appears to now be an international publication based in the USA i.e. may not know about the 2021 NICE Guideline, however, despite this fact there are a number of areas where this information could be significantly improved.
The ME Association
Letter
Dear Editorial at Britannica
I understand that you have already received some correspondence from the ME/CFS patient community regarding the information on ME/CFS on your website:
This obviously requires an urgent update as some of the information is inaccurate – certainly as far as the UK is concerned – and some of the content is not up to date with current medical opinion on ME/CFS.
In particular:
Epidemiology
The best epidemiological evidence we have so far suggests a prevalence rate of between 0.2% and 0.4% – although the number has significantly risen as a result of people developing ME/CFS after Covid 19.
Although delayed diagnosis and misdiagnosis certainly occurs there is no evidence that 90% of people are undiagnosed here in the UK.
Research into causation
We do, in fact know quite a lot about the cause of ME/CFS – in that it is probably a three stage illness involving predisposing factors (genetic predisposition), precipitating factors (viral infections and other immune system stressors) and perpetuating factors (abnormalities involving the brain, neuroendocrine and autonomic nervous system, immune system, and muscle energy production in the mitochondria).
Diagnosis
The 2021 UK NICE guideline on ME/CFS sets out a very clear symptom list and timeline pathway for making an early and accurate diagnosis.
This requires the presence of 4 key symptoms:
- 1 Activity induced fatigue that is not relieved by rest
- 2 Post exertional malaise/symptom exacerbation – a key diagnostic feature
- 3 Cognitive dysfunction
- 4 Unrefreshing sleep
If all of these 4 symptoms, and possibly others, are present for three months or more, and other explanations have been excluded, the diagnosis should be made at three months (not 6 months) from the onset of symptoms.
Although menopausal symptoms often cause an exacerbation of ME/CFS, this is not one of the important and common causes of misdiagnosis.
Management
As there is no treatment for ME/CFS, the most appropriate term is management.
The most important aspect of management is activity and energy management – known as pacing. The NICE guideline does NOT recommend exercise or graded exercise – as there is extensive patient evidence to indicate that exercise therapy makes people with ME/CFS worse.
There is no evidence that CBT can be used to treat ME/CFS – although it may sometimes help some people to cope with the emotional consequences of living with a long term debilitating condition.
Prognosis
Unfortunately, this information is over optimistic. Some people do make a degree of often fluctuating improvement over time but only a small proportion – no more than 5% to 10% – make a full and sustained recovery. Sadly, around 25% become severely or very severely affected – meaning they are housebound or even bedbound and require 24/7 care and even tube feeding. The prognosis is significantly better in children and adolescents.
Omission re Long Covid
I appreciate that you don't have a lot of space but it's important to point out that there are a lot of clinical and pathological overlaps between ME/CFS and Long Covid and that a substantial percentage of people with Long Covid (possibly around 50%) meet diagnostic criteria for ME/CFS.
Very happy to help in getting this information up to date.
Kind regards
Dr Charles Shepherd,
Trustee and Hon. Medical Adviser to the ME Association,
Member of the 2018-2021 NICE guideline on ME/CFS committee,
Member of the 2002 Chief Medical Officer's Working Group on ME/CFS
