key inclusion criteria: * willing and able to provide written informed consent, or with a legal representative who can provide informed consent, or enrolled under international conference on harmonization (ich) e6(r2) 4.8.15 emergency use provisions as deemed necessary by the investigator (age ≥ 18), or willing and able to provide assent (age ≥ 12 to \< 18, where locally and nationally approved) prior to performing study procedures * aged ≥ 18 years (at all sites), or aged ≥ 12 and \< 18 years of age weighing ≥ 40 kg (where permitted according to local law and approved nationally and by the relevant institutional review board (irb) or independent ethics committee (iec)) * severe acute respiratory syndrome coronavirus (sars-cov)-2 infection confirmed by polymerase chain reaction (pcr) test ≤ 4 days before randomization * currently hospitalized * peripheral capillary oxygen saturation (spo2) ≤ 94% or requiring supplemental oxygen at screening key

key inclusion criteria: * willing and able to provide written informed consent, or with a legal representative who can provide informed consent, or enrolled under international conference on harmonization (ich) e6(r2) 4.8.15 emergency use provisions as deemed necessary by the investigator (age ≥ 18), or willing and able to provide assent (age ≥ 12 to \< 18, where locally and nationally approved) prior to performing study procedures * aged ≥ 18 years (at all sites), or aged ≥ 12 and \< 18 years of age weighing ≥ 40 kg (where permitted according to local law and approved nationally and by the relevant institutional review board (irb) or independent ethics committee (iec)) * severe acute respiratory syndrome coronavirus (sars-cov)-2 infection confirmed by polymerase chain reaction (pcr) test ≤ 4 days before randomization * currently hospitalized * peripheral capillary oxygen saturation (spo2) ≤ 94% or requiring supplemental oxygen at screening key

key inclusion criteria: willing and able to provide written informed consent, or with a legal representative who can provide informed consent, or enrolled under international conference on harmonization (ich) e6(r2) 4.8.15 emergency use provisions as deemed necessary by the investigator (age ≥ 18), or willing and able to provide assent (age ≥ 12 to < 18, where locally and nationally approved) prior to performing study procedures aged ≥ 18 years (at all sites), or aged ≥ 12 and < 18 years of age weighing ≥ 40 kg (where permitted according to local law and approved nationally and by the relevant institutional review board (irb) or independent ethics committee (iec)) severe acute respiratory syndrome coronavirus (sars-cov)-2 infection confirmed by polymerase chain reaction (pcr) test ≤ 4 days before randomization currently hospitalized peripheral capillary oxygen saturation (spo2) ≤ 94% or requiring supplemental oxygen at screening key

key inclusion criteria: willing and able to provide written informed consent, or with a legal representative who can provide informed consent, or enrolled under international conference on harmonization (ich) e6(r2) 4.8.15 emergency use provisions as deemed necessary by the investigator (age ≥ 18), or willing and able to provide assent (age ≥ 12 to < 18, where locally and nationally approved) prior to performing study procedures aged ≥ 18 years (at all sites), or aged ≥ 12 and < 18 years of age weighing ≥ 40 kg (where permitted according to local law and approved nationally and by the relevant institutional review board (irb) or independent ethics committee (iec)) severe acute respiratory syndrome coronavirus (sars-cov)-2 infection confirmed by polymerase chain reaction (pcr) test ≤ 4 days before randomization currently hospitalized peripheral capillary oxygen saturation (spo2) ≤ 94% or requiring supplemental oxygen at screening key

key inclusion criteria: - willing and able to provide written informed consent, or with a legal representative who can provide informed consent, or enrolled under international conference on harmonization (ich) e6(r2) 4.8.15 emergency use provisions as deemed necessary by the investigator (age ≥18), or willing and able to provide assent (age ≥12 to <18, where locally and nationally approved) prior to performing study procedures - aged ≥ 18 years (at all sites), or aged ≥ 12 and < 18 years of age weighing ≥ 40 kg (where permitted according to local law and approved nationally and by the relevant institutional review board (irb) or independent ethics committee (iec)) - severe acute respiratory syndrome coronavirus (sars-cov)-2 infection confirmed by polymerase chain reaction (pcr) test ≤ 4 days before randomization - currently hospitalized - peripheral capillary oxygen saturation (spo2) ≤ 94% or requiring supplemental oxygen at screening key

key inclusion criteria: - willing and able to provide written informed consent, or with a legal representative who can provide informed consent, or enrolled under international conference on harmonization (ich) e6(r2) 4.8.15 emergency use provisions as deemed necessary by the investigator (age ≥18), or willing and able to provide assent (age ≥12 to <18, where locally and nationally approved) prior to performing study procedures - aged ≥ 18 years (at all sites), or aged ≥ 12 and < 18 years of age weighing ≥ 40 kg (where permitted according to local law and approved nationally and by the relevant institutional review board (irb) or independent ethics committee (iec)) - severe acute respiratory syndrome coronavirus (sars-cov)-2 infection confirmed by polymerase chain reaction (pcr) test ≤ 4 days before randomization - currently hospitalized - peripheral capillary oxygen saturation (spo2) ≤ 94% or requiring supplemental oxygen at screening key