Long Covid has shed new light on ME (chronic fatigue syndrome), once disparagingly dismissed as 'yuppie flu' – Professor Eleanor Riley

I am an inveterate seeker of silver linings. Not so much “glass half full” as always on the lookout for a quick top-up of the glass, however full (or empty) it is.

Given the slim pickings of the last year, I am tempted to grasp at one wee sliver of silver in suggesting that the pandemic – specifically some aspects of “long Covid” – has shone a welcome light on the long misunderstood condition known as myalgic encephalitis/chronic fatigue syndrome (ME/CFS).

Disparagingly dismissed by some as “yuppie flu” when first defined as a discrete disease entity in the 1980s and 1990s, ME/CFS is characterised by persistent or recurrent incapacitating fatigue, typically worsened by physical exertion and variably accompanied by muscle pain, sleep disruption, “brain fog” and other neurological symptoms.

Although the underlying cause is unknown, about half of newly diagnosed cases follow a ’flu-like illness. No particular infectious organism has been incriminated but herpes viruses (that cause glandular fever, chickenpox and shingles) and the bacterium that causes Lyme disease are among the potential triggers.

There is no definitive test for ME/CFS (diagnosis rests on persistence of key symptoms for at least six months in the absence of other known fatiguing conditions) and no generally accepted treatment.

The prognosis is highly variable with some people making a complete recovery over a few months or a couple of years, others having life-long remitting/relapsing disease with gradually longer remissions and fewer, shorter relapses. A small number of people are seriously disabled or bedridden for many years.

Although the “yuppie flu” moniker came from a perception that high-achievers who worked hard and played hard were at particular risk, it can strike anyone.

Long Covid has affected thousands of people in Scotland.

Previous robust good health and physical fitness appear to offer no protection and children can be as vulnerable as adults. Prior to the pandemic, ME/CFS was estimated to affect between 0.1 and two per cent of people across Europe with a tendency for it to be more common in females than males.

Disturbingly, however, an ME/CFS-like syndrome is emerging as a long-term consequence of Covid-19 The team behind the ZOE C-19 symptom-tracker app estimates that about 2.3 per cent of people who have tested positive for Covid-19 in the community (ie, those not seriously ill enough to be admitted to hospital) still have some symptoms 12 weeks later.

In some, the virus itself appears to have caused long-term damage to the lungs and other vital organs. However, many other long Covid sufferers report symptoms very reminiscent of classical ME/CFS, although they cannot be formally diagnosed as suffering from ME/CFS until they have been unwell with the key symptoms for at least six months.

It is too early to know how large this wave of apparent ME/CFS cases will be and how much suffering and despair it will leave behind; like so much else in this pandemic, only time will tell. But, for the first time, there will be a significant cohort of patients with the same, known trigger for their symptoms. This opens up a real opportunity for medical researchers to discover the molecular basis of the condition and – possibly – identify options for treatment.

Admittedly, as silver linings go, it isn’t much. But it is something.

Eleanor Riley is professor of immunology and infectious disease at the University of Edinburgh

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