General objectives
The main objectives of this cohort study are to provide follow-up data on persistent lung injury, self-reported pulmonary symptoms and symptoms of anxiety, depression and PTSD following hospitalization for COVID-19, and their association with clinical variables and biomarkers during hospitalization.

Bloodsamples of patients at 3 months and 12 months.

Predetermined hypotheses
• Only COVID-19 patients who were admitted to ICU have persistent clinical and radiological signs of pulmonary fibrosis after 12 months.
• The proportion of COVID-19 patients with symptoms of anxiety, depression and PTSD is higher in patients admitted to ICU than in general wards.
• Symptoms of anxiety, depression and PTSD and HRQoL improve from 3 to 12 months after hospitalization for COVID-19.

Specific objectives
Primary outcomes
1 a) The prevalence of restrictive lung function impairments and reduced gas diffusion after hospitalization for COVID-19.
1 b) The prevalence of interstitial lung findings 3 months and 1 year after hospitalization for COVID-19; GGO, reticular and linear pulmonary findings, scaring and fibrosis, nodular changes, consolidations, peripheral or central zonal dominance, apical or basal zonal dominance.

Secondary outcomes
2 a) Explore the associations between baseline characteristics during COVID-19 hospitalization and sustained reduced PFT and radiological signs of pulmonary fibrosis.
2 b) Assess the predictive value of surfactant protein A and D for sustained reduced PFT.
2 c) Explore the associations between novel serum and plasma biomarker levels during hospitalization for COVID-19 and reduced PFT or radiological signs of pulmonary fibrosis.
2 d) The prevalence and time course of anxiety, depression and PTSD following hospitalization for COVID-19, according to ICU treatment.
2 e) Explore the associations between baseline characteristics and persistent symptoms of anxiety, depression and PTSD.
2 f) Assess the HRQoL and changes in HRQoL following hospitalization for COVID-19, according to ICU treatment, age and gender.
2 g) Assess the 10-year mortality and prevalence of pulmonary disease following hospitalization for COVID-19.