- need for >4 liters nasal cannula oxygen to maintain oxygen saturation >90% - hypersensitivity to sirolimus - pregnant or breastfeeding - anticipated transfer to another study hospital within 72 hours - alanine transaminase (alt) >3 times the upper limit of normal - creatinine clearance <30ml/min as estimated by cockcroft-gault - underlying immunosuppression due to daily >5 mg prednisone equivalent a day, prior solid organ transplant, or other immunosuppression deemed by investigator to be potentially unsafe - co-administration with strong inhibitors of cyp3a4 and/or p-glycoprotein (p-gp) (such as ketoconazole, voriconazole, itraconazole, telithromycin, clarithromycin and others) - co-administration with strong inducers of cyp3a4 and/or p-glycoprotein (p-gp) (such as phenytoin or rifampin) - anticipated surgery within 1 month - need for healing of a fracture or a significant soft tissue wound

- need for >4 liters nasal cannula oxygen to maintain oxygen saturation >90% - hypersensitivity to sirolimus - pregnant or breastfeeding - anticipated transfer to another study hospital within 72 hours - alanine transaminase (alt) >3 times the upper limit of normal - creatinine clearance <30ml/min as estimated by cockcroft-gault - underlying immunosuppression due to daily >5 mg prednisone equivalent a day, prior solid organ transplant, or other immunosuppression deemed by investigator to be potentially unsafe - co-administration with strong inhibitors of cyp3a4 and/or p-glycoprotein (p-gp) (such as ketoconazole, voriconazole, itraconazole, telithromycin, clarithromycin and others) - co-administration with strong inducers of cyp3a4 and/or p-glycoprotein (p-gp) (such as phenytoin or rifampin) - anticipated surgery within 1 month - need for healing of a fracture or a significant soft tissue wound