Sick woman sitting on sofa covered in blanket with cup of tea and laptop

Helene Fox was recovering from surgery to remove endometriosis when she caught Covid-19. It had been six weeks since her laparoscopy and although she had been walking every day, following her surgeon’s instructions, she had only been on short 30-minute walks around her neighborhood. Then a sunny March day presented itself and Helene took advantage of it. “It was the first time I’d done a long walk through the park and along the canal in East London, and I was really excited because I thought, ‘Oh my God, I’ve got the energy for this. This is the beginning of my recovery.’”

The day after her glorious long walk, still feeling better, Helene went to the pub with friends. Ten of those friends, including Helene, ended up with Covid-19.

Helene describes her symptoms as exhaustion, shortness of breath and heaviness in the lungs. “It was in my chest. I had this pain right up underneath in my back … that was really aching. It felt like I’d been kicked in the back, and I had this constant heavy feeling on my chest.”

Helene’s friends gradually recovered and went back to work after one to two weeks. But Helene was nowhere near well enough to work. She put her slow recovery down to the surgery and the resulting pain and inflammation that she felt were still lingering in her body.

On day 16, Helene finally woke up with energy. “I did this long walk. I came back, and I was in the garden, lying in the sun. And then I felt I was getting a migraine.” At first, she thought nothing of it, putting it down to spring pollen causing hay fever. But then it got worse. “I developed this sinus pain and then it turned into nausea, and my whole body ached. So, I went to bed. I don’t think I was ever the same after that.”

Helene was recounting this story in August 2020, five months after contracting Covid-19. Her story is not unusual. Her description of feeling better and then getting even sicker after exercise has a medical name: post-exertional malaise. It is common in patients with post-viral fatigue and is a hallmark of chronic fatigue syndrome or myalgic encephalomyelitis (CFS/ME) and some other overlapping chronic pain conditions.

For the first few months of 2020, as the world was just beginning to comprehend what Covid-19 was, World Health Organization guidelines suggested people generally recovered from Covid-19 in two weeks.

By April, studies from Italy and China were documenting “a significant symptom burden in Covid-19 survivors including anxiety, sleep disorders, fatigue, limited exercise tolerance, and memory and executive function impairment”.

By July, the US Centers for Disease Control released a study that found 35% of people who tested positive for Covid-19 and had symptoms had not returned to their usual state of health two to three weeks after testing. Among those aged 18 to 34 with no prior medical conditions, one in five had not returned to their usual state of health.

In a 17 July interview, Dr Anthony Fauci said: “It’s extraordinary how many people have a post-viral syndrome that’s very strikingly similar to myalgic encephalomyelitis/chronic fatigue syndrome.”

CFS/ME is a complex and debilitating multi-system, chronic disease with a serious impact on one’s quality of life, characterized by reduced ability to perform pre-illness activity that lasts for more than six months and is accompanied by profound fatigue, which is not improved by rest. It affects between 0.2 and 0.4% of the population.

No one is suggesting that everyone who has Covid-19 symptoms beyond two weeks has post-viral fatigue or will develop CFS/ME. Too little is currently known about this disease to know where the disease ends and where post-viral fatigue sets in, and people with severe Covid-19 will obviously take longer to recover. But post-viral fatigue and CFS/ME are real and devastating.

Experts are adamant that we must act quickly to understand how viral infections lead to chronic fatigue and to prevent the worst from happening.