inclusion criteria: * has had sars-cov-2 positive antigen, rt-pcr, or other locally approved molecular diagnostic assay obtained within 5 days prior to randomization * has had symptoms consistent with covid-19 with onset 5 days before randomization * has one or more covid-19-related signs or symptoms on the day of randomization * phase 2: is an adult aged 18 years and above * phase 3: is an adult aged 18 years and above or is an adolescent aged 12 to 17 years (inclusive) and weighing ≥40 kg at the time of screening

inclusion criteria: * has had sars-cov-2 positive antigen, rt-pcr, or other locally approved molecular diagnostic assay obtained within 5 days prior to randomization * has had symptoms consistent with covid-19 with onset 5 days before randomization * has one or more covid-19-related signs or symptoms on the day of randomization * phase 2: is an adult aged 18 years and above * phase 3: is an adult aged 18 years and above or is an adolescent aged 12 to 17 years (inclusive) and weighing ≥40 kg at the time of screening

inclusion criteria: has had sars-cov-2 positive antigen, rt-pcr, or other locally approved molecular diagnostic assay obtained within 5 days prior to randomization has had symptoms consistent with covid-19 with onset 5 days before randomization has one or more covid-19-related signs or symptoms on the day of randomization phase 2: is an adult aged 18 years and above phase 3: is an adult aged 18 years and above or is an adolescent aged 12 to 17 years (inclusive) and weighing ≥40 kg at the time of screening

inclusion criteria: has had sars-cov-2 positive antigen, rt-pcr, or other locally approved molecular diagnostic assay obtained within 5 days prior to randomization has had symptoms consistent with covid-19 with onset 5 days before randomization has one or more covid-19-related signs or symptoms on the day of randomization phase 2: is an adult aged 18 years and above phase 3: is an adult aged 18 years and above or is an adolescent aged 12 to 17 years (inclusive) and weighing ≥40 kg at the time of screening

inclusion criteria: - has had sars-cov-2 positive antigen, rt-pcr, or other locally approved molecular diagnostic assay obtained within 5 days prior to randomization - has had symptoms consistent with covid-19 with onset 5 days before randomization - has one or more covid-19-related signs or symptoms on the day of randomization - is > 55 years of age or is 18 to ≤55 years of age with one or more preexisting medical conditions that place the participant at high risk of progression of covid-19

inclusion criteria: - has had sars-cov-2 positive antigen, rt-pcr, or other locally approved molecular diagnostic assay obtained within 5 days prior to randomization - has had symptoms consistent with covid-19 with onset 5 days before randomization - has one or more covid-19-related signs or symptoms on the day of randomization - is > 55 years of age or is 18 to ≤55 years of age with one or more preexisting medical conditions that place the participant at high risk of progression of covid-19