COVID-19 (coronavirus disease 2019) is a respiratory illness caused by the SARS-CoV-2 virus. COVID-19 most often causes respiratory symptoms that can feel much like a cold, the flu, or pneumonia. COVID-19 may attack more than your lungs and respiratory system. Other parts of your body may also be affected by the disease. Most people with COVID-19 have mild symptoms, but some people become severely ill. Learn more about COVID-19 and how it spreads.