Study: Initial Severity of COVID-19 Not Associated with Later Respiratory Complications


Liam Townsend, MD, and his co-authors looked at a number of measures of recovery for 153 patients who were followed in an outpatient clinic a median of 75 days after their COVID-19 diagnoses.

A study published in the Annals of the American Thoracic Society examined the recovery of lung function and overall wellness in individuals who had varying degrees of coronavirus disease 2019 (COVID-19) severity.

Little is known about lung health following infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and whether later respiratory problems, fatigue, and ill health are associated with the disease’s initial severity, according to the study.

Liam Townsend, MD, and his co-authors looked at a number of measures of recovery for 153 patients who were followed in an outpatient clinic a median of 75 days after their COVID-19 diagnoses.

"We found that fatigue, ill-health and breathlessness were all common following COVID-19," Townsend said in a press release. "However, these symptoms appeared to be unrelated to the severity of initial infection or any single measurement at the time of an outpatient appointment."

Townsend and his colleagues graded the patients’ initial infection severity as (1) not requiring admission; (2) requiring hospital admission; or (3) requiring ICU care. Further, nearly half of these patients required hospital admission during acute infection.

The researchers examined the association between the patients’ initial illness and abnormal chest X-ray, 6-minute walk test distance, and perception of maximal exertion during their follow-up appointments. Additionally, patients were asked about whether they felt fatigued and whether they thought they had returned to full health. These responses were graded using validated scales, according to the study authors.

The study team also looked at participants’ chest X-rays in order to detect persistent infection or significant scarring and performed CT imaging for patients with abnormal chest X-rays. Bloodwork was done to measure such indicators of disease as C-reactive protein, which increases when there is inflammation in the body.

"We were surprised by our findings. 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 severity of initial infection, which was not the case," Townsend said in a press release.

The study findings suggest that COVID-19 does not cause significant fibrosis, with lung scarring seen on CT scans of only 4% of study participants, following X-ray detection of earlier abnormalities in a larger group.

Patients who felt they had to exert themselves during moderate exercise also reported they felt fatigued and in poor health, with 62% of patients indicating that they had not returned to full health and 47% being classified as having fatigue. In addition, the patients’ length of inpatient hospital stays and frailty were associated with covering less distance in the walk test.

"These findings have implications for clinical care, in that they demonstrate the importance of following up all patients who were diagnosed with COVID-19, irrespective of severity of initial infection. It is not possible to predict who will have ongoing symptoms," Townsend said in a press release.


Initial severity of COVID-19 not associated with later respiratory complications. EurekAlert! Published January 8, 2021. Accessed January 8, 2021.

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