To measure the effectiveness of sargramostim on restoring lung homeostasis, the primary endpoint of this intervention is measuring oxygenation after 5 DAYS of inhaled (and intravenous) treatment through assessment of pretreatment (day 0) and post-treatment (day 5) ratio of PaO2/FiO2 and through measurement of the P(A-a)O2 gradient, which can easily be performed in the setting of clinical observation of patients admitted to the COVID -19 ward or ICU COVID-19 unit. Preferentially, this measurement should be done in the upright position, while breathing room air for a minimum of 3 minutes.. If this is impossible due to need for supplemental oxygen, FiO2 and oxygen supplementation method should be recorded in patient record, so that A-a gradient can be normalized for age expected normal A-a gradient while on supplemental oxygen use. During the 5 day treatment period, we will perform daily measurements of oxygen saturation (pulse oximetry) in relation to FiO2, and the slope of alterations in this parameters could also be an indicator that our hypothesis is correct. If the patient leaves hospital prior to the day 6 analysis point, oxygenation at day of discharge will be used as value for measuring primary endpoint.

To measure the effectiveness of sargramostim on restoring lung homeostasis, the primary endpoint of this intervention is measuring oxygenation after 5 DAYS of inhaled (and intravenous) treatment through assessment of pretreatment (day 0) and post-treatment (day 5) ratio of PaO2/FiO2 and through measurement of the P(A-a)O2 gradient, which can easily be performed in the setting of clinical observation of patients admitted to the COVID -19 ward or ICU COVID-19 unit. Preferentially, this measurement should be done in the upright position, while breathing room air for a minimum of 3 minutes.. If this is impossible due to need for supplemental oxygen, FiO2 and oxygen supplementation method should be recorded in patient record, so that A-a gradient can be normalized for age expected normal A-a gradient while on supplemental oxygen use. During the 5 day treatment period, we will perform daily measurements of oxygen saturation (pulse oximetry) in relation to FiO2, and the slope of alterations in this parameters could also be an indicator that our hypothesis is correct. If the patient leaves hospital prior to the day 6 analysis point, oxygenation at day of discharge will be used as value for measuring primary endpoint.