inclusion criteria: * age ≥ 18 years * positive for severe acute respiratory syndrome coronavirus-2 (sars-cov-2) infection as determined using a molecular diagnostic test (reverse transcription polymerase chain reaction \[rt-pcr\] or equivalent) approved by regulatory authorities (including food and drug administration or brazilian health regulatory agency) or allowed under an emergency use authorization within 14 days before screening. if a false negative result is suspected, the sars-cov-2 test may be repeated within the screening period. * chest ct scan or x ray results confirming interstitial pneumonia * severe covid 19 disease as evidenced by ≥ 1 of the following criteria at screening including within 24 hours before screening: * respiratory frequency \> 30 breaths per minute * spo2 ≤ 93% on room air * ratio of partial pressure of arterial oxygen to fraction of inspired oxygen (pao2/fio2) \< 300 * ratio of arterial oxygen saturation to fraction of inspired oxygen (sao2/fio2 ratio) \< 218 (if pao2/fio2 ratio is not available) * radiographic lung infiltrates \> 50%

inclusion criteria: * age ≥ 18 years * positive for severe acute respiratory syndrome coronavirus-2 (sars-cov-2) infection as determined using a molecular diagnostic test (reverse transcription polymerase chain reaction \[rt-pcr\] or equivalent) approved by regulatory authorities (including food and drug administration or brazilian health regulatory agency) or allowed under an emergency use authorization within 14 days before screening. if a false negative result is suspected, the sars-cov-2 test may be repeated within the screening period. * chest ct scan or x ray results confirming interstitial pneumonia * severe covid 19 disease as evidenced by ≥ 1 of the following criteria at screening including within 24 hours before screening: * respiratory frequency \> 30 breaths per minute * spo2 ≤ 93% on room air * ratio of partial pressure of arterial oxygen to fraction of inspired oxygen (pao2/fio2) \< 300 * ratio of arterial oxygen saturation to fraction of inspired oxygen (sao2/fio2 ratio) \< 218 (if pao2/fio2 ratio is not available) * radiographic lung infiltrates \> 50%

inclusion criteria: - age ≥ 18 years - positive for severe acute respiratory syndrome coronavirus-2 (sars-cov-2) infection as determined using a molecular diagnostic test (reverse transcription polymerase chain reaction [rt-pcr] or equivalent) approved by regulatory authorities (including food and drug administration or brazilian health regulatory agency) or allowed under an emergency use authorization within 14 days before screening. if a false negative result is suspected, the sars-cov-2 test may be repeated within the screening period. - chest ct scan or x ray results confirming interstitial pneumonia - severe covid 19 disease as evidenced by ≥ 1 of the following criteria at screening including within 24 hours before screening: - respiratory frequency > 30 breaths per minute - spo2 ≤ 93% on room air - ratio of partial pressure of arterial oxygen to fraction of inspired oxygen (pao2/fio2) < 300 - ratio of arterial oxygen saturation to fraction of inspired oxygen (sao2/fio2 ratio) < 218 (if pao2/fio2 ratio is not available) - radiographic lung infiltrates > 50%

inclusion criteria: - age ≥ 18 years - positive for severe acute respiratory syndrome coronavirus-2 (sars-cov-2) infection as determined using a molecular diagnostic test (reverse transcription polymerase chain reaction [rt-pcr] or equivalent) approved by regulatory authorities (including food and drug administration or brazilian health regulatory agency) or allowed under an emergency use authorization within 14 days before screening. if a false negative result is suspected, the sars-cov-2 test may be repeated within the screening period. - chest ct scan or x ray results confirming interstitial pneumonia - severe covid 19 disease as evidenced by ≥ 1 of the following criteria at screening including within 24 hours before screening: - respiratory frequency > 30 breaths per minute - spo2 ≤ 93% on room air - ratio of partial pressure of arterial oxygen to fraction of inspired oxygen (pao2/fio2) < 300 - ratio of arterial oxygen saturation to fraction of inspired oxygen (sao2/fio2 ratio) < 218 (if pao2/fio2 ratio is not available) - radiographic lung infiltrates > 50%