COVID-19 may not be just one disease, but six distinct types, a new British study claims. Each type differs in severity and in the need for respiratory support during hospitalization, the researchers added. Cough, fever and loss of smell are the usual symptoms of COVID-19, but the range of symptoms can include headaches, muscle pain, fatigue, diarrhea, confusion, loss of appetite, shortness of breath and more. For the study, the researchers analyzed data on 1,600 people who reported their symptoms into an app.