The purpose of this study is to compare the effects, good or bad, of two doses of TCZ in combination with standard of care treatment on subjects with moderate to severe COVID-19 pneumonia. This study is testing a drug called tocilizumab (TCZ). During this study, you will be hospitalized and have study procedures daily until discharged (based on your study doctor's decision). After you are discharged from the hospital, you are encouraged to come back for additional assessments; if it is not possible, you may be followed up by telephone by your study doctor or study nurse.
About 100 people will take part in this study in the United States.