This is a phase 1 study in which healthy adult volunteers will receive BRII-196/BRII-198 or placebo and will be assessed for safety, tolerability, and pharmacokinetics.

Inclusion Criteria:

1. Subject must be 18 to 49 years of age inclusive
2. Body weight ≤100 kg and body mass index (BMI) within the range of 19.0-26.0kg/m2 (inclusive).
3. Male or female

Exclusion Criteria:

1. Any clinically significant chronic or acute medical condition that makes the volunteer unsuitable for participation.
2. A history of significant hypersensitivity, intolerance, or allergy to any drug compound
3. History of alcohol or other substance abuse