In pneumonia, the lungs become filled with fluid and inflamed, leading to breathing difficulties. For some people, breathing problems can become severe enough to require treatment at the hospital with oxygen or even a ventilator.
The pneumonia that COVID-19 causes tends to take hold in both lungs at the same time. Air sacs in the lungs fill with fluid, limiting their ability to take in oxygen and causing shortness of breath, cough and other symptoms.
While most people recover from pneumonia without any lasting lung damage, the pneumonia associated with COVID-19 can be severe. Even after the disease has passed, lung injury may result in breathing difficulties that might take months to improve. If you are experiencing a worsening cough or shortness of breath, see your doctor immediately.