COVID-19 is the disease caused by a novel species of coronavirus that humans currently have very little immunity to. Scientists and doctors are learning new things every day, but right now it appears to cause a respiratory tract infection in most patients. Currently doctors can only offer supportive treatment to patients; there is no cure.
While most people infected will recover on their own, a significant percentage will require hospitalization. Low-end death rate estimates are 1%, 10 times the death rate of the seasonal flu. The best thing we can all do to protect ourselves and our community is to stay home.