Concentration of REGN10983 + REGN10987 in Serum Over Time (Ph3 Cohort 2);Number of Participants With Hypersensitivity Reactions (Ph1, Ph2, Ph3 Cohort 1 - Cohort 3);Number of Participants With Infusion-related Reactions (Ph1, Ph2, Ph3 Cohort 1 - Cohort 3);Number of Participants With Treatment-emergent Serious Adverse Events (SAEs) - [Ph1, Ph2, Ph3 Cohort 1 - Cohort 3];Proportion of Participants With at Least One (≥1) COVID-19-related Hospitalization or All-cause Death (Ph3 Cohort 1- 1.2g vs Placebo);Proportion of Participants With at Least One (≥1) COVID-19-related Hospitalization or All-cause Death (Ph3 Cohort 1 - 2.4g vs Placebo);Time-weighted Average Change From Baseline in Viral Load (log10 Copies/mL) From Day 1 to Day 7, as Measured by Quantitative Reverse Transcription Quantitative Polymerase Chain Reaction (RT-qPCR) in Nasopharyngeal (NP) Swab Samples (Ph1, Ph2)

Concentration of REGN10983 + REGN10987 in Serum Over Time (Ph3 Cohort 2);Number of Participants With Hypersensitivity Reactions (Ph1, Ph2, Ph3 Cohort 1 - Cohort 3);Number of Participants With Infusion-related Reactions (Ph1, Ph2, Ph3 Cohort 1 - Cohort 3);Number of Participants With Treatment-emergent Serious Adverse Events (SAEs) - [Ph1, Ph2, Ph3 Cohort 1 - Cohort 3];Proportion of Participants With at Least One (≥1) COVID-19-related Hospitalization or All-cause Death (Ph3 Cohort 1- 1.2g vs Placebo);Proportion of Participants With at Least One (≥1) COVID-19-related Hospitalization or All-cause Death (Ph3 Cohort 1 - 2.4g vs Placebo);Time-weighted Average Change From Baseline in Viral Load (log10 Copies/mL) From Day 1 to Day 7, as Measured by Quantitative Reverse Transcription Quantitative Polymerase Chain Reaction (RT-qPCR) in Nasopharyngeal (NP) Swab Samples (Ph1, Ph2)

Concentration of REGN10933 in serum over time;Concentration of REGN10987 in serum over time;Proportion of patients with at least one (≥1) COVID-19-related hospitalization or all-cause death;Proportion of patients with hypersensitivity reactions;Proportion of patients with infusion-related reactions;Proportion of patients with treatment-emergent serious adverse events (SAEs);Time-weighted average change from baseline in viral load (log10 copies/mL), as measured by quantitative reverse transcription quantitative polymerase chain reaction (RT-qPCR) in nasopharyngeal (NP) swab samples

Concentration of REGN10933 in serum over time;Concentration of REGN10987 in serum over time;Proportion of patients with at least one (≥1) COVID-19-related hospitalization or all-cause death;Proportion of patients with hypersensitivity reactions;Proportion of patients with infusion-related reactions;Proportion of patients with treatment-emergent serious adverse events (SAEs);Time-weighted average change from baseline in viral load (log10 copies/mL), as measured by quantitative reverse transcription quantitative polymerase chain reaction (RT-qPCR) in nasopharyngeal (NP) swab samples

Concentration of REGN10933 in serum over time;Concentration of REGN10987 in serum over time;Cumulative incidence of patients with at least one (≥1) COVID-19 related medically attended visit or all-cause death;Incidence of ADA to REGN10987;Incidence of anti-drug antibodies (ADA) to REGN10933;Incidence of NAb to REGN10987;Incidence of neutralizing antibody (NAb) to REGN10933;Proportion of patients with hypersensitivity reactions;Proportion of patients with infusion-related reactions;Proportion of patients with treatment-emergent serious adverse events (SAEs);Time-weighted average change from baseline in viral load (log10 copies/mL), as measured by quantitative reverse transcription quantitative polymerase chain reaction (RT-qPCR) in nasopharyngeal (NP) swab samples

Concentration of REGN10933 in serum over time;Concentration of REGN10987 in serum over time;Cumulative incidence of patients with at least one (≥1) COVID-19 related medically attended visit or all-cause death;Incidence of ADA to REGN10987;Incidence of anti-drug antibodies (ADA) to REGN10933;Incidence of NAb to REGN10987;Incidence of neutralizing antibody (NAb) to REGN10933;Proportion of patients with hypersensitivity reactions;Proportion of patients with infusion-related reactions;Proportion of patients with treatment-emergent serious adverse events (SAEs);Time-weighted average change from baseline in viral load (log10 copies/mL), as measured by quantitative reverse transcription quantitative polymerase chain reaction (RT-qPCR) in nasopharyngeal (NP) swab samples

Concentration of REGN10933 in serum over time;Concentration of REGN10987 in serum over time;Cumulative Incidence of COVID-19 related medically attended visits;Incidence of ADA to REGN10987;Incidence of anti-drug antibodies (ADA) to REGN10933;Incidence of NAb to REGN10987;Incidence of neutralizing antibody (NAb) to REGN10933;Proportion of patients with hypersensitivity reactions;Proportion of patients with infusion-related reactions;Proportion of patients with treatment-emergent serious adverse events (SAEs);Time-weighted average change from baseline in viral load (log10 copies/mL), as measured by quantitative reverse transcription quantitative polymerase chain reaction (RT-qPCR) in nasopharyngeal (NP) swab samples;Time-weighted average change from baseline in viral load (log10 copies/mL), as measured by RT-qPCR in NP swab samples

Concentration of REGN10933 in serum over time;Concentration of REGN10987 in serum over time;Cumulative Incidence of COVID-19 related medically attended visits;Incidence of ADA to REGN10987;Incidence of anti-drug antibodies (ADA) to REGN10933;Incidence of NAb to REGN10987;Incidence of neutralizing antibody (NAb) to REGN10933;Proportion of patients with hypersensitivity reactions;Proportion of patients with infusion-related reactions;Proportion of patients with treatment-emergent serious adverse events (SAEs);Time-weighted average change from baseline in viral load (log10 copies/mL), as measured by quantitative reverse transcription quantitative polymerase chain reaction (RT-qPCR) in nasopharyngeal (NP) swab samples;Time-weighted average change from baseline in viral load (log10 copies/mL), as measured by RT-qPCR in NP swab samples

Proportion of patients with hypersensitivity reactions;Proportion of patients with at least one COVID-19 related medically attended visit;Time-weighted average change from baseline in viral shedding as measured by quantitative reverse transcription quantitative polymerase chain reaction (RT-qPCR) in nasopharyngeal (NP) swab samples;Proportion of patients with infusion-related reactions;Proportion of patients with treatment-emergent serious adverse events (SAEs)

Proportion of patients with hypersensitivity reactions;Proportion of patients with at least one COVID-19 related medically attended visit;Time-weighted average change from baseline in viral shedding as measured by quantitative reverse transcription quantitative polymerase chain reaction (RT-qPCR) in nasopharyngeal (NP) swab samples;Proportion of patients with infusion-related reactions;Proportion of patients with treatment-emergent serious adverse events (SAEs)