Additional Study Information: The main purpose of this study is to determine if sarilumab is safe and if it can decrease the amount of time a person has COVID-19 symptoms. Sarilumab (also known as Kevzara ) is considered an investigational drug in this study because it has not been approved for marketing by any health authority for the condition being studied but it has been approved in multiple countries for active rheumatoid arthritis. Sarilumab is a type of drug called a monoclonal antibody. An antibody is a special kind of protein that one's immune (defense) system normally makes to fight bacteria and viruses. Scientists can now make antibodies in the laboratory and produce them for the treatment of many different diseases. Sarilumab has been specifically shown to block the action of a protein called interleukin-6 (IL-6) in the body. Interleukin-6 (IL-6) is a protein in the immune system that has been shown to play an important role in inflammation. Inflammation may be associated with complications of COVID-19.