Introduction: There remains uncertainty regarding the long-term sequelae of COVID-19 infection. While the prevalence of parenchymal abnormalities following hospitalisation has been quantified (Stewart et al, AJRCCM 2022), the burden of disease amongst those who did not require admission remains unknown.

Aims & Objectives: The UKILD study aims to assess the prevalence of residual lung abnormalities (RLA) following SARS-CoV-2 infection in patients who did not require hospitalisation (Wild et al, BMJ Open Resp Res, 2021).

Methods: Patients were recruited from post-COVID clinics across the UK in this prospective multicentre observational cohort study. Those who had objective evidence of COVID infection and a subsequent CT scan were eligible for inclusion. Patients who had pre-existing lung disease or had been hospitalised with COVID-19 were excluded. CT scans were performed at least three months after initial infection.

Results: The preliminary analysis assessed 90 CT scans at an average of seven months following infection. RLA were seen in 32 (36%) scans, of which nine had an alternative diagnosis at least as likely as post-COVID changes. Among the remaining 23, ground glass opacity was the most common change (65%), followed by consolidation (16%). Fibrotic changes were seen in five cases (6% of the total). Changes affected <10% of the lungs in 19 cases, with more extensive ground glass change affecting >10% of lung in four scans (4.4% of the total).

Conclusions: This cohort of non-hospitalised patients with symptoms severe enough to warrant imaging reveal a substantial burden of RLA. Further investigation will establish whether these changes persist over longer periods of time and will aim to identify underlying mechanisms.