This study looks at the safety and effectiveness of different drugs in treating COVID-19 in outpatients.

In Phase II, participants in the study will be treated with either a study drug or with a placebo.

In protocol version 7.0, participants in Phase III of the study will be treated with either a study drug or an active comparator drug.

Participants assigned to the bamlanivimab agent/placebo arm and will have 28 days of intensive follow-up following study drug administration, followed by limited follow-up through 24 weeks in phase II and in phase III.

All other investigational agents and their corresponding placebo arms will involve 28 days of intensive follow-up, followed by limited follow-up through 72 weeks in phase II and phase III.