Some COVID-19 patients have preexisting conditions such as asthma or lung disease, and almost 1 out of 3 COVID-19 patients may develop acute respiratory distress syndrome, study sponsors said. Fluid may leak into the lungs, causing hypoxemia, or low levels of oxygen in the blood, which can lead to shortness of breath. The condition can be fatal, and may leave survivors with weakness, fatigue and a decreased quality of life.