In September 2021, Gez Medinger made a really bad decision. A film-maker who had been a superfit marathon runner, he caught Covid in the first wave and was subsequently crippled by fatigue. On days when he felt well, he scoured medical journals and patient-support networks for anything that might help, sharing what he found on YouTube.

Ivermectin was one such hope. Medinger got hold of some pills but, after taking them for six days, he was admitted to hospital. His lymph nodes had swelled up to the size of golf balls, most of his skin flaked off and he was constantly shivering. It took five days of intravenous fluids before he was well enough to go home.

Medinger is the coauthor of The Long Covid Handbook, one of two books about the illness. Medinger’s collaborator is immunologist Dr Danny Altmann, a professor of immunology at Imperial College London in the UK who specialises in post-vi-ral conditions. “The knowledge we now have about long Covid is fast forward times 10,” he says. “I know as much about long Covid in two years as I’ve known about many other diseases in perhaps 20, 30 or 40 years.” But for Medinger, who originally trained as a scientist, progress still feels glacial.

“For most conditions, there’s a pathway that is understood — even if you don’t get a pill, at least you understand what happens next. That’s beenthe thing that’s really difficult to navigate for long Covid, because that pathway doesn’t exist. But there is also a part of me that says, my God, there are more eyeballs, more test tubes being pointed at this than there ever was for ME/CFS.”

He is referring to myalgic encephalomyelitis, also known as chronic fatigue syndrome, a post-viral condition which shares many key symptoms with long Covid, including fatigue that is worsened by activity and not significantly relieved by rest, unrefreshing sleep and brain fog.

For decades, controversy has surrounded ME/CFS, with some sceptics dismissing it as hysteria, partly because it’s a relapsing or remitting condition, so sufferers may superficially appear well — but also because, as with long Covid, roughly 70 per cent of patients are women (a fact attributed to the more “activatable” female immune system). Put bluntly, they were simply not believed.

But, two and a half years since the term long Covid was coined by a sufferer on Twitter, what do we know about what causes it and how to treat it?

There are over 200 symptoms, including fatigue, brain fog, chest pain or tightness, insomnia, heart palpitations, dizziness, joint pain, depression and anxiety, tinnitus and ear-aches, nausea, stomach aches, skin problems, headaches andcontinued loss of taste andsmell. What is perhaps hardest to deal with is that it is relapsing/ remitting.

“There are days, or even hours within days, where you feel almost normal,” says Medinger. “And then, an houror two later, bam, you’re toast. It’s the unpredictability of the condition that makes it so phenomenally hard to manage.”

Both The Long Covid Handbook, and Breaking Free from Long Covid by Dr Lucy Gahanare fascinating in that they are written by “patient activists”.

As for what causes somepeople to recover from a Covidinfection and others to develop long Covid, there are many theories — and perhaps multiple causes — from organ damageand immune dysregulation, tothe theory of a reservoir of live virus hiding in the body long after it has vanished from the nose and throat.

Based on his patient surveys, Medinger suggests that the most common symptom cluster includes increased heart rate (palpitations), nausea, dizziness (especially on standing), insomnia, anxiety, chest pain, vision problems and irregular temperature regulation. These could be related to dysautonomia and postural orthostatic tachycardia syndrome (PoTS). Dysautonomia refers to a malfunctioning of the autonomic nervous system — things the body normally does automatically, like breathing, digestion — while PoTS is when your heart rate shoots up when you sit or stand up, something that can leave people bed bound.

As with ME/CFS, there is also a degree of controversy to the question of who is more prone to the condition. As Medinger writes, “If you were to distil all the evidence (and anecdotal observations) for predisposing factors into one character, they would look like this: Elsie is female, aged between 30 and 50, and previously lived an extremely active life. She’s not very good at taking breaks or slowing down. She has a history of mild asthma and had glandular fever when at university. If she were a friend of mine I’d be advising her to take it very easy in the weeks after a Covid infection.”

None of this is to say that developing long Covid is your fault; but the best advice to anyone who catches Covid is to rest as much as you can, both physically and cognitively. As for treatments that work, it’s still very early days.