Lung ultrasonography (LUS) is an important diagnostic and monitoring technique in individuals with current COVID-19 infection. However, less is known regarding the changes in LUS results following a COVID-19 hospitalization. Adult participants in a prospective, longitudinal trial with COVID-19 enlisted from non-ICU hospital units had 8-zone LUS and blood collection during hospitalization and 2–3 months after release. Blinded to clinical factors and outcomes, LUS pictures were evaluated.

A total of 71 patients with interpretable LUS at baseline and follow-up were included (mean age 64 years, 61% male, 24% with acute respiratory distress syndrome (ARDS)). The follow-up LUS was done 72 days on average following the initial LUS during hospitalization. At baseline, 87% of patients showed pathologic LUS findings in ≥1 zone (e.g., ≥3 B-lines, confluent B-lines, or subpleural or lobar consolidation), whereas 30% did at follow-up (P<0.001). From hospitalization to follow-up, the total number of B-lines and LUS score reduced dramatically (median 17 vs. 4, P<0.001 and 4 vs. 0, P<0.001, respectively). On the follow-up LUS, 28% of all patients had ≥3 B-lines in ≥1 zone, whereas 47% of those with ARDS during the baseline hospitalization (n = 17) had  ≥3 B-lines in ≥1 zone. In COVID-19 survivors, LUS results improved considerably from hospitalization to follow-up 2–3 months following release. However, persistent B-lines were common during follow-up, especially among those who had ARDS at the start.