To Evaluate SCTA01 Treatment of High-risk Outpatients With COVID-19

Inclusion Criteria: * Male or non-pregnant female adults, ≥18 years old of age at the time of randomization; * Participants should have at least one of COVID-19 risk factor; * Participants should have at least 2 COVID-19 related symptoms; * Has symptoms consistent with COVID-19 as determined by the investigator with onset ≤7 days before randomization; * First positive SARS-CoV-2 viral infection tested (PCR or antigen-based diagnostic tests) in samples collected ≤3 days prior to start of the infusion; * Participants are currently not hospitalized; * Participant (or legal authorized representative) has signed the ICF before any clinical activity related to SCTA01 trial; * Women with childbearing potential must agree to use effective contraceptive methods during the study period; * Patient should not participate in other clinical studies related to COVID-19 or SARS-CoV-2 infection. Exclusion Criteria: * Have known allergies to any of the components used in the formulation of the SCTA01/placebo; * Participants with a history of severe anaphylaxis, such as severe anaphylactic reaction, urticaria, and angioedema; * Have SpO2 ≤ 93% on room air at sea level or PaO2/FiO2 \< 300, respiratory rate ≥30 per minute, heart rate ≥125 per minute (FDA); * Require mechanical ventilation or anticipated impending need for mechanical ventilation; * Suspected or proven serious bacterial, fungal, viral, or other infection (besides COVID-19) that in the opinion of the investigator could constitute a risk when taking part in this study; * Have any serious concomitant systemic disease, condition or disorder that, in the opinion of the investigator, should preclude participation in this study; * Have any co-morbidity requiring surgery within \<29 days, or that is considered life threatening within 29 days; * Have a history of previous SARS-CoV-2 infection; * Received convalescent plasma, COVID-19 vaccine, or anti-SARS-CoV-2 spike(S) protein targeted therapy; * Have participated in a clinical study involving an investigational intervention within past 30 days or 5-half lives of investigational product, whichever is longer; * Have received an investigational intervention for SARS-CoV-2 prophylaxis within 30 days before dosing; * Pregnant or lactating women; * Anticipated hospitalization or transfer to another medical site which is not a study site within 72 hours; * Participants unable to follow the protocol during the study; * Participants deemed inappropriate for enrollment by the investigator due to other factors.