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Long COVID and the body systems it affects

Long COVID and the body systems it affects

October 10, 2022 By admin

  1. Trisha Greenhalgh, professor of primary care health sciences 1,  
  2. Manoj Sivan, associate professor in rehabilitation medicine 2,  
  3. Brendan Delaney, professor of medical informatics and decision making3,  
  4. Rachael Evans, associate professor in respiratory medicine, associate professor in respiratory medicine4,  
  5. Ruairidh Milne, person with long covid and, emeritus professor of public health5
    Author affiliations
  1. Correspondence to T Greenhalgh

What you need to know

  • Long covid (prolonged symptoms following covid-19 infection) is common

  • The mainstay of management is supportive, holistic care, symptom control, and detection of treatable complications

  • Many patients can be supported effectively in primary care by a GP with a special interest

This article updates and extends a previous BMJ Practice Pointer published in August 2020 when almost no peer reviewed research or evidence based guidance on the condition was available.1 In this update we outline how clinicians might respond to the questions that patients ask.


The term “long covid”2 refers to prolonged symptoms following infection with SARS-CoV-2 that are not explained by an alternative diagnosis. It embraces the National Institute for Health and Care Excellence (NICE)’s terms “ongoing symptomatic covid-19” (symptoms lasting 4-12 weeks) and “post covid-19 syndrome” (symptoms beyond 12 weeks),3 the US Centers for Disease Control and Prevention’s group of “post-covid conditions,”4 and the World Health Organization’s “post covid-19 condition.”5


In mid-2022, approximately 70% of the UK adult population had been infected with SARS-CoV-2.6 Of these, almost 2 million report covid-19 symptoms persisting for more than four weeks; 807 000 (41% of all people with long covid) for more than a year; and 403 000 (19%) for more than two years.7 Based on workforce data from the British Medical Association,8 a full time equivalent general practitioner with an average list size (approximately 2000) has around 65 patients with long covid, 27 of whom will have been unwell for more than a year, and 12 for more than two years. Most general practices have far fewer patients with a long covid diagnostic code on their electronic health record9 for a combination of reasons, including lack of presentation, lack of recognition, and inadequate coding. These figures do not cover children, who are outside the scope of this article.

Rates of long covid are lower in people who are triple vaccinated, but prevalence of long covid (persistent symptoms at 12-16 weeks after laboratory confirmed SARS-CoV-2 infection) remains high at 5% for the delta variant and 4.2% for omicron BA.2.10

Symptoms and case definition

Long covid may be diagnosed late or not at all,11 12 13 so both generalists and specialists should be alert to it as a differential, while also being aware that patients can develop other persistent symptoms following acute covid-19 that are not necessarily caused by covid-19. Long covid is characterised by a constellation of general and organ specific symptoms, the commonest of which are summarised in the infographic. These multiple manifestations lead to difficulties with daily activities such as washing and dressing, low exercise tolerance, and impaired ability to work (either at all or partially), and result in reduced quality of life.5 15 16 17 18 19

Symptoms typically occur across multiple systems concurrently but sometimes one organ system (eg, cardiovascular) dominates. Phenotyping studies have identified several symptom clusters (table 1), with severe cases characterised by greater number and intensity of symptoms and greater functional impairment.333435 Some patients’ long covid follows a fairly constant course, while others experience relapsing and remitting symptoms, sometimes with particular triggers.36

Table 1

Symptoms, investigation, and management of long covid

Fatigue—described by one patient as “like the most severe jet lag and hangover I’ve ever had”37—is the commonest symptom and may be associated with severe functional impairment; reduced exercise tolerance is also common. Some patients develop post-exertional malaise (PEM) or post-exertional symptom exacerbation (PESE),11 defined as worsening of symptoms following physical or mental exertion, typically 12 to 48 hours after activity and lasting days or (rarely) weeks.38 Long covid has evident (but under-researched) overlaps with chronic fatigue and myalgic encephalomyelitis.39 Box 1 gives examples of patients’ accounts.

Box 1

Patients’ accounts of long covid symptoms and accessing services, from research interviews with people with long covid13 40 41

“I had an odd rash for quite a while; it kept coming and going … very itchy cough … very mild asthma … I started getting the odd headache again …. Pins and needles, feet going completely numb … all sorts of odd symptoms, I just kept putting it down to grief until a couple of months in, a friend said, ‘Look, do you think this could be covid?’”

“The fatigue is literally like hitting a wall. I can’t stay awake any more. It’s just like, wow, I have to go to bed.”

“I’d had 11 days of feeling great. And after [a particular] weekend I crashed again. And again it seemed to last for weeks of having these waves of symptoms: shortness of breath, diarrhoea, muscle aches, complete fatigue.”

“I think it [consultation with general practitioner] was a really positive experience and I felt really listened to, and she was able to be honest at that point and said I don’t really know what I can do to help you but you can phone me or email me at any point.”

“My last interaction with my GP was in June. I asked about my lungs, and he said, ‘What do you want me to do about it? You tell me. I have no idea.’ It felt very dismissive […]. ‘Nothing’s got any evidence so, yeah sorry, I can’t help.’ I went back to work after five weeks still very unwell because nobody believed in long covid in May, they just didn’t believe it.”

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