Similarly, we find enrichment of several markers of pulmonary fibrosis (CLU, COL1A1, COL1A2, and COL3A1) in SARS-CoV-2-low samples as compared with nonviral and viral ARDS samples, exemplifying the profound lung injury and fibrosis during later stages of COVID-19. This evidence concerns the gene COL1A1 and pulmonary fibrosis.