‘Long Covid’ can affect people even with mild initial symptoms – study

TCD researchers find persistent fatigue and ill-health unrelated to severity of infection

Persistent ill-health can result from contracting Covid-19 regardless of the severity of the initial infection, according to the findings of a new study by a team of Irish researchers.

In what was the first global study of its kind, researchers from Trinity College Dublin assessed lung function and respiratory symptoms among 153 patients infected with Covid-19, including those who self-isolated at home and others who required ICU care in hospital.

The study's lead author, Liam Townsend, research fellow at TCD's Department of Clinical Medicine and specialist registrar at St James's Hospital, said little had previously been known about lung health following infection with the virus that causes Covid-19 and whether there were links between respiratory problems, fatigue and ill-health and the initial severity of the disease.

While fatigue, ill-health and breathlessness were all common symptoms as a result of Covid-19 infection, Dr Townsend said they appeared to be unrelated to the severity of the initial infection.


Chest X-ray

All patients who participated in the study were given a chest X-ray and six-minute walk test.

Dr Townsend admitted that researchers were surprised at the findings of the study, which is published in the latest edition of the Annals of the American Thoracic Society.

“We expected a greater number of abnormal chest X-rays. We also expected the measures of ongoing ill-health and abnormal findings to be related to the severity of initial infection, which was not the case,” Dr Townsend said.

Researchers examined a number of measures of recovery for the patients who attended an outpatient clinic, with a median of 75 days after they had been diagnosed with Covid-19.

The findings of the study suggest that Covid-19 does not cause significant fibrosis as only 4 per cent of patients showed signs of lung scarring on CT scans.

‘Full health’

It found that 62 per cent of patients felt they had not returned to full health, while 47 per cent were classified as having fatigue.

“Patients who felt they had to exert themselves during moderate exercise also reported they felt fatigue and poor health,” Dr Townsend said.

He said the findings showed patients experienced significant symptoms, but there was a relatively low rate of people with abnormal X-rays.

Dr Townsend said the results highlighted how there is no simple diagnostic test to predict which patients with Covid-19 will suffer long-term effects such as fatigue.

Dr Townsend said it was important that all patients diagnosed with Covid-19 received follow-up treatment, irrespective of whether they suffered mild or severe infection.

The study suggested the highest-risk group for suffering post-Covid symptoms appeared to be females under 60 years, which Dr Townsend said indicated genetic factors might be a factor.