PERSISTENT fatigue occurs in more than half of Covid-19 patients - regardless of the seriousness of their infection.

A new study, carried out researchers in Ireland, examined 128 patients around 10 weeks on from clinical recovery from the virus.

They found no association between severity of the infection - such as a person ending up in hospital - and subsequent fatigue, but did discover higher rates of fatigue among women and individuals with a pre-existing diagnosis of depression or anxiety.

It comes amid growing concern about the number Covid 'long-haulers' - patients who recover from the infection but experience lasting health problems including profound fatigue, brain fog, and constant headaches.

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The condition has been dubbed 'long Covid' and appears similar to other post-viral syndromes, such as chronic fatigue - also known as ME.

Dr Liam Townsend, who led the research with colleagues at St James's Hospital and the Trinity Translational Medicine Institute in Dublin, said: "Whilst the presenting features of SARS-CoV-2 infection have been well-characterised, the medium and long-term consequences of infection remain unexplored.

"In particular, concern has been raised that SARS-CoV-2 has the potential to cause persistent fatigue, even after those infected have recovered from Covid-19.

"In our study, we investigated whether patients recovering from SARS-CoV-2 infection remained fatigued after their physical recovery, and to see whether there was a relationship between severe fatigue and a variety of clinical parameters."

The findings will be presented next week at the ESCMID Conference on Coronavirus Disease, the first major international congress on the pandemic, which will be hosted online from Wednesday.

Doctors assessed fatigue using a common clinical tool known as the Chalder Fatigue Score.

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They recorded whether patients had required hospital admission, critical, or intensive care, and measured the aggressiveness of the the immune response based on data such as white blood cell counts and levels of C-reactive protein.

Of the patients who took part in the study, 71 (55.5%) had been admitted to hospital due to Covid while 57 (44.5%) recovered in the community, with no need for hospital care, but the likelihood of suffering fatigue was the same in both groups.

"Fatigue was found to occur independent of admission to hospital, affecting both groups equally," said Dr Townsend.

However, females and those with a pre-existing diagnosis of depression or anxiety were over-represented in the fatigue group - by 13% compared to 1.6% in the non-fatigue group.

Overall, 67 out of the 128 participants experienced post-Covid fatigue.

The authors conclude: "This study highlights the importance of assessing those recovering from Covid-19 for symptoms of severe fatigue, irrespective of severity of initial illness, and may identify a group worthy of further study and early intervention."

The ESCMID Conference on Coronavirus Disease will be held online from September 23-25.