Working or residing in an environment with high risk of exposure to SARS-CoV-2 for whom exposure may be relatively prolonged or for whom personal protective equipment (PPE) may be inconsistently used, especially in confined settings. Phase 2 only: Screening laboratory results within normal limits for testing laboratory or are deemed not clinically significant by the Investigator. Be post-menopausal or be surgically sterile or have a partner who is sterile or use medically effective contraception with a failure rate of < 1% per year when used consistently and correctly from Screening until 3 months following last dose (Phase 2) or until last dose (Phase 3).

Working or residing in an environment with high risk of exposure to SARS-CoV-2 for whom exposure may be relatively prolonged or for whom personal protective equipment (PPE) may be inconsistently used, especially in confined settings. Phase 2 only: Screening laboratory results within normal limits for testing laboratory or are deemed not clinically significant by the Investigator. Be post-menopausal or be surgically sterile or have a partner who is sterile or use medically effective contraception with a failure rate of < 1% per year when used consistently and correctly from Screening until 3 months following last dose (Phase 2) or until last dose (Phase 3).