Figure 2.

Pulmonary function of COVID-19 survivors and matched non-COVID-19 controls

(A–C) Longitudinal evolution of lung function in COVID-19 survivors with different disease severity scales (scale 3: not requiring supplemental oxygen during hospitalisation; scale 4: requiring supplemental oxygen via nasal cannulae or mask during hospitalisation; scale 5–6: requiring high-flow nasal cannula, non-invasive mechanical ventilation, or invasive mechanical ventilation during hospitalisation). (D–F) Comparison of lung function between COVID-19 survivors with different disease severity and their controls at the 2-year follow-up visit. FEV₁=forced expiratory volume in 1 s. FVC=forced vital capacity. TLC=total lung capacity. FRC=functional residual capacity. DLCO=diffusion capacity for carbon monoxide. *p<5·56 × 10⁻³ for the comparison of different time points in (A), (B), and (C). †p<0·0167 for the comparison of COVID-19 survivors with controls in (D), (E), and (F).