Prevalence: Latest research suggests a 62% increase on historic estimates for ME/CFS in the UK

The ME Association has reached agreement with Action for ME that we will each adopt the latest research evidence from Professor Chris Ponting and Gemma Samms at the University of Edinburgh.

This suggests that 403,922 or 0.6% of adults and children in the UK would have a lifetime prevalence of ME/CFS (a 62% increase from historic estimates of 250,000), if there were minimal social and healthcare barriers to a diagnosis.

We have also agreed that we will use a figure of 950,000 (or 1.4%) as an estimate of adults and children in the UK who experienced an infectious trigger of Covid-19 and could meet the diagnostic criteria for ME/CFS (NICE Guideline NG206). This is based on 2023 estimates from the Office for National Statistics (ONS) and will be updated when more reliable research becomes available.

Therefore, we feel the estimated prevalence of people with a potential diagnosis of ME/CFS could be as high as 1.35million in the UK (1.14million in England, 38,000 in Northern Ireland, 109,000 in Scotland, and 63,000 in Wales), representing a considerable health burden on the NHS and social care services and reinforcing the need for good quality care and support.

Geographic Breakdown

• 1. ME/CFS: Using the 403,922 UK prevalence for ME/CFS (see Ponting and Samms research below)
• 2. Covid-19 ME/CFS: ONS Data (March 2023 below) and assuming 50% of 1.9M (950,000) meet criteria
• 3. Population: ONS UK Population estimates by country (Mid-2023), Table 1

Establishing an estimate of people with ME/CFS

We don’t know precisely how many people are affected by ME/CFS in the UK today.

• Not everyone receives the correct diagnostic code on their medical records for example, and despite many parliamentary questions over the years to the Department of Health and Social Care, NHS England and other health authorities have failed to give a proper accounting.
• Making an accurate diagnosis has been historically hampered by the lack of a diagnostic test and varying degrees of medical uncertainty which has led to uneven rates of diagnosis across the country.
• It is very likely that there are more people who are symptomatic but have not received a diagnosis, particularly in respect of other-than-white populations, people who live in deprived areas of the country, those who are misdiagnosed, and those who are missed altogether.

We can only make an estimate of the likely numbers affected based on good quality epidemiological research. This was provided in April 2025 by Professor Chris Ponting and Gemma Samms (DecodeME) from the University of Edinburgh, in a study that was funded by ME Research UK.

• Unequal access to diagnosis of myalgic encephalomyelitis in England, BMC Public Health, 2025.

This research examined hospital admission and outpatient appointments in England from April 1989 to October 2023. The total dataset was for 62,782,175 individuals.

Ponting and Samms then reviewed entries for people with the G93.3 (Postviral Fatigue Syndrome (PVFS)) International Classification of Diseases (ICD-10) diagnostic code on their hospital records and concluded a prevalence of 0.16%.

This code was used because it was the most relevant ICD-10 code for ME/CFS, and research conducted using data from the UK Biobank had suggested that 72% of those with a G93.3 code on their records had further evidence of ME/CFS.

• The ICD provides coding for every known disease and the NHS bases in its own diagnostic coding system – SNOMED-CT – on it. PVFS was listed in ICD-10 as a parent term under ‘other disorders of the brain’ i.e., a neurological disease, and featured ‘benign myalgic encephalomyelitis’ as the only entry.

It is important to note that if an individual was diagnosed in primary care by a GP and the same code was not used or reported at a hospital outpatient appointment or admission, then they would not have been picked up by this research.

When examining UK Biobank data, the researchers found that only 28% of those with a GP code on their medical records also had a code for ICD-10 G93.3. It is hard to quantify how much this might affect the results, but it could mean a significant underestimate.

Ponting and Samms tried to adjust for this likelihood, while accounting for the significant variation in diagnoses across different groups (ethnicity, location, and age). They estimated the number of people in the UK who would have a diagnosis and a recorded code (i.e., G93.3) if there was minimal social and healthcare barriers to a diagnosis, and for this they used the data from the Cornwall and Isles of Scilly Integrated Care Board.

Cornwall and the Isles of Scilly had recorded the oldest population of people with ME/CFS, the highest recorded number with a diagnosis, the highest female to male ratio and the lowest other-than-white population. The maximal prevalence for white females and males was 0.92% and 0.25% respectively.

Ponting and Samms commented that even if some of the 403,922 people did not meet a strict case definition for ME/CFS, this would likely be offset by those diagnosed by GPs in the NHS or privately, who did not have the G93.3 coding, and those who did not have a likely infectious onset to ME/CFS.

Establishing an estimate of people with Covid-19 ME/CFS

Attempts to determine how many people have ME/CFS became more complicated during and after the pandemic and the predictable emergence of Long Covid.

A significant proportion of those unable to recover from a Covid-19 infection are likely to meet the diagnostic criteria for ME/CFS. Indeed, more people are now likely to be receiving an ME/CFS diagnosis than Long Covid.

Since testing for Covid-19 was terminated, we have seen referrals to Long Covid clinics fall quite dramatically in some areas while referrals to ME/CFS services have risen, leading to longer wait times.

Long Covid clinics have also been closed which has left ME/CFS services as the only viable specialist referral option, although in some areas of England, but especially in Wales, new ‘Post-Viral’ specialist services have or are being commissioned that will accept referrals for both.

The research from Ponting and Samms (above) did not consider the impact of Covid-19 on the number of people diagnosed with ME/CFS. Their estimates were based on those with a recorded code of G93.3 (Postviral Fatigue Syndrome) on hospital admittance or outpatient records up to October 2023. It may well have picked up some people whose trigger was Covid-19, but we don’t really know.

We have agreed to use a figure of 950,000 to account for the research from America (below) that has suggested between 40-60% of people with ‘Long Covid’ could meet the diagnostic criteria for ME/CFS i.e., they have all the relevant symptoms including post-exertional malaise and no organ damage that has resulted from a Covid-19 infection.

• Bonilla et al. ME/CFS is common in post-acute sequelae of SARS-CoV-2 infection (PASC): Results from a post-COVID-19 multidisciplinary clinic | February 2023
• Jason et al. ME/CFS and Post-Exertional Malaise among Patients with Long COVID | December 2022

Prevalence estimates for Long Covid in the UK come from data published by the Office for National Statistics (ONS), although these estimates were based on self-reported Long Covid and not a clinical diagnosis and so we have treated them with caution.

• In England and Scotland (data released in April 2024), an estimated 3.3% (2million people) were experiencing self-reported Long Covid (symptoms persisting beyond 4 weeks after an infection). 1.5million people (75%) experienced symptoms that adversely affected daily activities, with 381,000 (19.2%) reporting their ability to undertake daily activities had been ‘limited a lot’.

An earlier release (March 2023) reported 2.9% of the UK population (1.9million people) were self-reporting Long Covid, with symptoms adversely affecting the daily activities of 1.5million (79%) and 381,000 (20%) reporting activities had been ‘limited a lot’.

The estimate we are using is based on this earlier data, and we have concluded that around 50% of 1.9million people i.e., 950,000 with Long Covid could meet a clinical diagnosis (NICE) of ME/CFS. We will revise these estimates when more reliable research evidence becomes available.

• ONS: Self-reported coronavirus (COVID-19) infections and associated symptoms, England and Scotland: November 2023 to March 2024.
• ONS: Prevalence of ongoing symptoms following coronavirus (COVID-19) infection in the UK: 30 March 2023.

More information

• We will be updating the MEA website and related MEA literature with these newly agreed estimates as soon as possible.
• We have published a booklet: Long Covid and ME/CFS: Are they the same condition? Available to download for free from the website.
• We are currently updating the leaflet: Prognosis, Permanency and Quality of Life, but it will be available soon for free from the website.
• The NICE Guideline on ME/CFS (NG206) is a comprehensive set of clinical recommendations that we would strongly suggest both carers and patients read to better understand what can be expected from the NHS and social care services, and to learn more about the process of obtaining a diagnosis and how specialist services can provide help and support.
• The NICE Rapid Guideline on Long Covid (NG188) is available but incomplete and unlike the Guideline on ME/CFS hasn’t been published as a full guideline because the evidence-base is still developing. The last update was made in January 2024.

Russell Fleming
Head of Project Development,
The ME Association