They are similar to some extent. For instance, for both severe COVID-19 and pulmonary edema, the lungs are wet, and there are many fluids in the ling, causing the similar clinical symptoms of difficulty breathing. But severe COVID-19 is more difficult to treat, because you just cannot get rid of the virus by any medications. The patient has to rely on his/her own immune system to get rid of the virus. By comparison, for high-altitude pulmonary edema, you just have to lower the altitude, and the pulmonary edema will go away.