The primary objectives are:

• To assess the occurrence of adverse events of special interest (AESIs) in participants treated with repeated subcutaneous (SC) doses of REGN10933+REGN10987 compared to placebo
• To assess the concentrations of REGN10933 and REGN10987 in serum over time after single and repeated SC administration

The secondary objectives are:

• To assess the safety and tolerability of repeated SC doses of REGN10933+REGN10987 compared to placebo
• To assess attainment of target concentrations of REGN10933 and REGN10987 in serum after single and repeated SC administration
• To assess the immunogenicity of REGN10933 and REGN10987

Key Inclusion Criteria:

1. Is healthy or has chronic medical condition(s) that is stable and well controlled as per the opinion of the investigator and is not likely to require medical intervention through the end of study
2. Stable medication for co-morbid condition(s) for at least 6 months prior to screening
3. Willing and able to comply with study visits and study-related procedures, including compliance with site precautionary requirements related to SARS-CoV-2 infection and transmission

Key Exclusion Criteria:

1. Positive diagnostic test for SARS-CoV-2 infection ≤72 hours prior to randomization
2. Subject-reported clinical history of COVID-19 as determined by investigator
3. Subject-reported history of prior positive diagnostic test for SARS-CoV-2 infection
4. Active respiratory or non-respiratory symptoms suggestive or consistent with COVID-19
5. Medically attended acute illness, systemic antibiotics use, or hospitalization (ie, >24 hours) for any reason within 30 days prior to screening
6. Acute exacerbation of a chronic pulmonary condition (eg, chronic obstructive pulmonary disease [COPD], asthma exacerbations) in the past 6 months prior to screening
7. Received investigational or approved SARS-CoV-2 vaccine
8. Received investigational or approved passive antibodies for SARS-CoV-2 infection prophylaxis as defined in the protocol
9. Use of remdesivir, intravenous immunoglobulin (IVIG), or other anti-SARS viral agents within 2 months prior to screening

NOTE: Other protocol-defined Inclusion/ Exclusion criteria apply

All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing

Individual anonymized participant data will be considered for sharing once the indication has been approved by a regulatory body, if there is legal authority to share the data and there is not a reasonable likelihood of participant re-identification.

Qualified researchers may request access to anonymized patient level data or aggregate study data when Regeneron has received marketing authorization from major health authorities (e.g., FDA, European Medicines Agency [EMA], Pharmaceuticals and Medical Devices Agency [PMDA], etc) for the product and indication, has the legal authority to share the data, and has made the study results publicly available (eg, scientific publication, scientific conference, clinical trial registry).