Inclusion Criteria:  COVID-19 symptoms (fever, cough, sore throat, malaise, headache, muscle pain, dyspnea at rest or with exertion, confusion, or respiratory distress), diagnosis of COVID-19 pneumonia with an admission chest x-ray demonstrating multilobar ground glass infiltrates consistent with COVID-19 pneumonia. room air estimated PaO2/FiO2 ratio between 150 -280 must correct to a pulse oximetry of 90% or better using no more than 5 liters of low flow supplemental oxygen must be enrolled within 24 hours of hospital admission  Exclusion Criteria:  immunocompromised due to current use of immunosuppressive drugs or chemotherapy, have a history of HIV/organ transplant/ active hepatitis B or C, or are on hemodialysis or peritoneal dialysis currently on oxygen supplementation greater than low flow nasal cannula (including home oxygen therapy; CPAP for obstructive sleep apnea is not an exclusion) have DNR status or not expected to survive >7 days experiencing shock (on vasopressors) or multiple organ dysfunction or failure are co-infected with influenza A or B history of DVT or PE within last 12 weeks currently pregnant or nursing participating in another therapeutic trial allergic to cromolyn sodium.