Intended for healthcare professionals

Letters When will we be well again?

Covid-19 and chronic fatigue

BMJ 2020; 370 doi: (Published 30 July 2020) Cite this as: BMJ 2020;370:m2922
  1. Frances M K Williams, professor of genomic epidemiology and honorary consultant rheumatologist1,
  2. Nina Muirhead, dermatology surgeon2,
  3. Carmine Pariante, professor of biological psychiatry3
  1. 1King’s College London, London SE1 7EH, UK
  2. 2Buckinghamshire NHS Trust, Amersham, UK
  3. 3Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
  1. frances.williams{at}

Salisbury’s article on patients with prolonged symptoms of covid-19 should be distributed to all healthcare practitioners.1 Chronic fatigue is an important and distressing symptom in rheumatic2 and other diseases3 as well as in the complex multisystem disease myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).4 It is poorly covered in many medical school curriculums. At last there is positive news: a medical education course on ME/CFS5 has been set up and is freely accessible (

Chronic fatigue is common in the general population, with a prevalence in adults of 30%; ME/CFS has a prevalence of 1%.4 There is clear evidence of a genetic basis to chronic fatigue with heritability estimates of 50%,6 and detectable metabolic abnormalities are seen in patients’ blood.78 Covid-19 can, like many flu-like illnesses, lead to unpleasant malaise and severe, acute fatigue9 but also to chronic fatigue with a prevalence of around 10% at three months. Postviral fatigue studies have shown that blood concentrations of IL-6 and IL-10 in the acute phase can predict the development of subsequent chronic fatigue.10 That the same pro-inflammatory mediators are seen in the cytokine storm of severe covid-19 infection suggests a pattern of immune activation that requires urgent and immediate investigation.11

The covid-19 epidemic will be a considerable ongoing burden to healthcare services, and the chronic fatigue element must not go unrecognised, lacking as it does at present validated and accepted biomarkers. We need an urgent and coherent response from the medical community with early recognition, support, advice, and evidence based management as best we can provide it given the novel virus. Patients with chronic fatigue are likely to present in increased numbers to all forms of medical practice worldwide.


  • Competing interests: None declared.


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