Concern coronavirus may trigger post-viral fatigue syndromes.

COULD the coronavirus sweeping around the world have a second illness following in its wake? We may expect to see an outbreak of post-viral fatigue syndromes in some people who have had covid-19, according to some researchers.

Viral infections have previously been linked to problems with long-term fatigue symptoms. For example, chronic fatigue syndrome (CFS), which is also called myalgic encephalomyelitis (ME), sometimes occurs after viral infections. People who have CFS experience extreme fatigue and a range of other symptoms, such as pain and sensitivity to light, but the condition is poorly understood.

So is it possible that the coronavirus could trigger similar fatigue syndromes? There are hints from the related SARS virus that this may happen. After the SARS outbreak of 2002 to 2003, some people in Toronto, Canada, who were infected were recorded as experiencing fatigue, muscle weakness and sleep problems up to three years later.

During Toronto's SARS outbreak, 273 people were diagnosed with the infection, of whom 44 died. After the outbreak had ended, Harvey Moldofsky, at the time a psychiatrist and sleep specialist at the University of Toronto, was asked to study 22 of those who had been infected and now had ongoing health problems that stopped them going back to work.

I think the coronavirus will lead to many, many cases of post-infective fatigue syndrome

Moldofsky's team published its work in 2011. The researchers found that the participants generally had disturbed sleep, daytime fatigue, pain and weakness in muscles all over their body, and depression. “These symptoms were very reminiscent of CFS/ME,” says Moldofsky.

His team only studied around 8 per cent of those diagnosed with SARS in Toronto, so we don't know what proportion of people who had SARS experienced these symptoms afterwards. Nor is it known how long such symptoms lasted.

While the current covid-19 pandemic is caused by a different virus, it is a member of the same coronavirus family, so it might also cause a post-viral fatigue syndrome, says Moldofsky. “That's what I'm worried about.”

Other viruses are known to trigger CFS after infection, such as the Epstein-Barr virus, says Simon Wessely, former president of the Royal College of Psychiatrists. “We don't know about corona, but I think it will lead to many, many cases of post-infective fatigue syndrome.”

“There is a long history of infections as a trigger but other factors contributing to longer term disability,” adds Wessely. “If the virus is found to enter the brain, this might increase the risk.”

“It's quite likely that some people will be developing a post-viral fatigue syndrome, which may then lead into an ME/CFS-like illness,” says Charles Shepherd, a medical adviser to the ME Association, a UK patient charity. “What happens to people after the acute infection is clearly something that needs to be researched.”

It may be a long time before we know more, as people need to have symptoms for at least six months before being diagnosed with CFS or ME, says Mark Guthridge at Deakin University in Melbourne, Australia, who has ME himself.