Inclusion Criteria:  Adults ≥ 18 years of age Approval from the patient's primary inpatient service Hospitalized Diagnosed with COVID-19 pneumonia Positive test for active SARS-CoV-2 infection Requiring supplemental oxygen ≥ 5LNC or ≥ 40% FiO2. Chest computed tomography (CT) at admission with < 10% pulmonary fibrosis Ability to provide written informed consent on the part of the subject or, in the absence of decisional capacity of the subject, an appropriate surrogate (e.g. a legally authorized representative).  Exclusion Criteria:  Known diagnosis of previous pulmonary fibrosis or an interstitial lung disease. Clinical features or known diagnosis of malignancy or active non-COVID-19 infection, including untreated latent tuberculosis. History of unstable or deteriorating cardiac disease (including myocardial infarction, coronary artery bypass surgery or angioplasty within the past 6 months, congestive heart failure requiring hospitalization within the past 6 months, or uncontrolled arrhythmia. Known history of hypersensitivity to sirolimus. History of unstable or deteriorating neurologic disease (including TIAs or stroke). Pregnant or lactating females. Females of child bearing potential are required to have a negative pregnancy test prior to treatment and practice abstinence or prevent pregnancy by at least a barrier method of birth control. Investigational therapy for any indication within 28 days prior to treatment. Current treatment with any drugs that are strong inhibitors of CYP3A4. Tofacitinib Clarithromycin Telithromycin Nefazodone Itraconazole Ketoconazole Atazanavir Darunavir Indinavir Lopinavir Nelfinavir Ritonavir Saquinavir Tipranavir. Inability or unwillingness to comply with the requirements for the trial.