inclusion criteria: 1. provision of signed and dated informed consent form (either by the individual or by the individual's healthcare proxy). 2. stated willingness to comply with all study procedures and availability for the duration of the study 3. male or female aged 18-85. 4. discharged from recent hospitalization for severe covid-19 disease requiring supplemental oxygen but not requiring mechanical ventilation or ecmo or dialysis. 5. must be between 4 to 20 weeks since onset of acute covid-19 symptoms onset. 6. no return to baseline health or hiatus between acute covid-19 and onset of post-acute covid-19 or chronic post-covid-19 syndrome. 7. current sars-cov-2 rt pcr must be negative prior to enrollment. 8. at least 2 or more persistent symptoms frequently reported for post-acute covid-19 or chronic post-covid-19 syndrome such as fatigue, cough, headache, body aches, fever, chills, loss of taste, loss of smell, diarrhea, congestion, dyspnea, sore throat, chest pain, abdominal pain, confusion, or vomiting must be moderate in severity based on modified cdc symptoms questionnaire (see section 11.1 for severity scoring system). 9. medical resource council dyspnea score of \< 3 out of 5. 10. baseline eq-5d-5l must be higher than 21211. (of note: eq-5d-5l has 5 dimensions: mobility, self-care, usual activities, pain/discomfort, anxiety/depression. each dimension is scored from 1 (full) to 5 (worst), such that a score of 11111 is reflective of full quality-of-life and a score of 55555 is reflective of worst quality-of-life.) 11. baseline 6-minute walk test (6-mwt) is 500 meters or less. 12. supplemental oxygen should be ≤5 l o2/min. 13. if the candidate is either male or female of reproductive potential, he or she must agree to use of double barrier method of highly effective birth control contraception such as condoms with oral contraceptive pill or choose to remain abstinent if already practicing abstinence during the screening period. the duration of required usage of double barrier method or maintenance of abstinence must include the time from the beginning of the screening period until 90 days following the last dose of the study treatment.

inclusion criteria: 1. provision of signed and dated informed consent form (either by the individual or by the individual's healthcare proxy). 2. stated willingness to comply with all study procedures and availability for the duration of the study 3. male or female aged 18-85. 4. discharged from recent hospitalization for severe covid-19 disease requiring supplemental oxygen but not requiring mechanical ventilation or ecmo or dialysis. 5. must be between 4 to 20 weeks since onset of acute covid-19 symptoms onset. 6. no return to baseline health or hiatus between acute covid-19 and onset of post-acute covid-19 or chronic post-covid-19 syndrome. 7. current sars-cov-2 rt pcr must be negative prior to enrollment. 8. at least 2 or more persistent symptoms frequently reported for post-acute covid-19 or chronic post-covid-19 syndrome such as fatigue, cough, headache, body aches, fever, chills, loss of taste, loss of smell, diarrhea, congestion, dyspnea, sore throat, chest pain, abdominal pain, confusion, or vomiting must be moderate in severity based on modified cdc symptoms questionnaire (see section 11.1 for severity scoring system). 9. medical resource council dyspnea score of \< 3 out of 5. 10. baseline eq-5d-5l must be higher than 21211. (of note: eq-5d-5l has 5 dimensions: mobility, self-care, usual activities, pain/discomfort, anxiety/depression. each dimension is scored from 1 (full) to 5 (worst), such that a score of 11111 is reflective of full quality-of-life and a score of 55555 is reflective of worst quality-of-life.) 11. baseline 6-minute walk test (6-mwt) is 500 meters or less. 12. supplemental oxygen should be ≤5 l o2/min. 13. if the candidate is either male or female of reproductive potential, he or she must agree to use of double barrier method of highly effective birth control contraception such as condoms with oral contraceptive pill or choose to remain abstinent if already practicing abstinence during the screening period. the duration of required usage of double barrier method or maintenance of abstinence must include the time from the beginning of the screening period until 90 days following the last dose of the study treatment.

inclusion criteria: provision of signed and dated informed consent form (either by the individual or by the individual's healthcare proxy). stated willingness to comply with all study procedures and availability for the duration of the study male or female aged 18-85. discharged from recent hospitalization for severe covid-19 disease requiring supplemental oxygen but not requiring mechanical ventilation or ecmo or dialysis. must be between 4 to 20 weeks since onset of acute covid-19 symptoms onset. no return to baseline health or hiatus between acute covid-19 and onset of post-acute covid-19 or chronic post-covid-19 syndrome. current sars-cov-2 rt pcr must be negative prior to enrollment. at least 2 or more persistent symptoms frequently reported for post-acute covid-19 or chronic post-covid-19 syndrome such as fatigue, cough, headache, body aches, fever, chills, loss of taste, loss of smell, diarrhea, congestion, dyspnea, sore throat, chest pain, abdominal pain, confusion, or vomiting must be moderate in severity based on modified cdc symptoms questionnaire (see section 11.1 for severity scoring system). medical resource council dyspnea score of < 3 out of 5. baseline eq-5d-5l must be higher than 21211. (of note: eq-5d-5l has 5 dimensions: mobility, self-care, usual activities, pain/discomfort, anxiety/depression. each dimension is scored from 1 (full) to 5 (worst), such that a score of 11111 is reflective of full quality-of-life and a score of 55555 is reflective of worst quality-of-life.) baseline 6-minute walk test (6-mwt) is 500 meters or less. supplemental oxygen should be ≤5 l o2/min. if the candidate is either male or female of reproductive potential, he or she must agree to use of double barrier method of highly effective birth control contraception such as condoms with oral contraceptive pill or choose to remain abstinent if already practicing abstinence during the screening period. the duration of required usage of double barrier method or maintenance of abstinence must include the time from the beginning of the screening period until 90 days following the last dose of the study treatment.

inclusion criteria: provision of signed and dated informed consent form (either by the individual or by the individual's healthcare proxy). stated willingness to comply with all study procedures and availability for the duration of the study male or female aged 18-85. discharged from recent hospitalization for severe covid-19 disease requiring supplemental oxygen but not requiring mechanical ventilation or ecmo or dialysis. must be between 4 to 20 weeks since onset of acute covid-19 symptoms onset. no return to baseline health or hiatus between acute covid-19 and onset of post-acute covid-19 or chronic post-covid-19 syndrome. current sars-cov-2 rt pcr must be negative prior to enrollment. at least 2 or more persistent symptoms frequently reported for post-acute covid-19 or chronic post-covid-19 syndrome such as fatigue, cough, headache, body aches, fever, chills, loss of taste, loss of smell, diarrhea, congestion, dyspnea, sore throat, chest pain, abdominal pain, confusion, or vomiting must be moderate in severity based on modified cdc symptoms questionnaire (see section 11.1 for severity scoring system). medical resource council dyspnea score of < 3 out of 5. baseline eq-5d-5l must be higher than 21211. (of note: eq-5d-5l has 5 dimensions: mobility, self-care, usual activities, pain/discomfort, anxiety/depression. each dimension is scored from 1 (full) to 5 (worst), such that a score of 11111 is reflective of full quality-of-life and a score of 55555 is reflective of worst quality-of-life.) baseline 6-minute walk test (6-mwt) is 500 meters or less. supplemental oxygen should be ≤5 l o2/min. if the candidate is either male or female of reproductive potential, he or she must agree to use of double barrier method of highly effective birth control contraception such as condoms with oral contraceptive pill or choose to remain abstinent if already practicing abstinence during the screening period. the duration of required usage of double barrier method or maintenance of abstinence must include the time from the beginning of the screening period until 90 days following the last dose of the study treatment.

inclusion criteria: 1. provision of signed and dated informed consent form (either by the individual or by the individual's healthcare proxy). 2. stated willingness to comply with all study procedures and availability for the duration of the study 3. male or female aged 18-85. 4. discharged from recent hospitalization for severe covid-19 disease requiring supplemental oxygen but not requiring mechanical ventilation or ecmo or dialysis. 5. must be between 4 to 20 weeks since onset of acute covid-19 symptoms onset. 6. no return to baseline health or hiatus between acute covid-19 and onset of post-acute covid-19 or chronic post-covid-19 syndrome. 7. current sars-cov-2 rt pcr must be negative prior to enrollment. 8. at least 2 or more persistent symptoms frequently reported for post-acute covid-19 or chronic post-covid-19 syndrome such as fatigue, cough, headache, body aches, fever, chills, loss of taste, loss of smell, diarrhea, congestion, dyspnea, sore throat, chest pain, abdominal pain, confusion, or vomiting must be moderate in severity based on modified cdc symptoms questionnaire (see section 11.1 for severity scoring system). 9. medical resource council dyspnea score of < 3 out of 5. 10. baseline eq-5d-5l must be higher than 21211. (of note: eq-5d-5l has 5 dimensions: mobility, self-care, usual activities, pain/discomfort, anxiety/depression. each dimension is scored from 1 (full) to 5 (worst), such that a score of 11111 is reflective of full quality-of-life and a score of 55555 is reflective of worst quality-of-life.) 11. baseline 6-minute walk test (6-mwt) is 500 meters or less. 12. supplemental oxygen should be ≤5 l o2/min. 13. if the candidate is either male or female of reproductive potential, he or she must agree to use of double barrier method of highly effective birth control contraception such as condoms with oral contraceptive pill or choose to remain abstinent if already practicing abstinence during the screening period. the duration of required usage of double barrier method or maintenance of abstinence must include the time from the beginning of the screening period until 90 days following the last dose of the study treatment.

inclusion criteria: 1. provision of signed and dated informed consent form (either by the individual or by the individual's healthcare proxy). 2. stated willingness to comply with all study procedures and availability for the duration of the study 3. male or female aged 18-85. 4. discharged from recent hospitalization for severe covid-19 disease requiring supplemental oxygen but not requiring mechanical ventilation or ecmo or dialysis. 5. must be between 4 to 20 weeks since onset of acute covid-19 symptoms onset. 6. no return to baseline health or hiatus between acute covid-19 and onset of post-acute covid-19 or chronic post-covid-19 syndrome. 7. current sars-cov-2 rt pcr must be negative prior to enrollment. 8. at least 2 or more persistent symptoms frequently reported for post-acute covid-19 or chronic post-covid-19 syndrome such as fatigue, cough, headache, body aches, fever, chills, loss of taste, loss of smell, diarrhea, congestion, dyspnea, sore throat, chest pain, abdominal pain, confusion, or vomiting must be moderate in severity based on modified cdc symptoms questionnaire (see section 11.1 for severity scoring system). 9. medical resource council dyspnea score of < 3 out of 5. 10. baseline eq-5d-5l must be higher than 21211. (of note: eq-5d-5l has 5 dimensions: mobility, self-care, usual activities, pain/discomfort, anxiety/depression. each dimension is scored from 1 (full) to 5 (worst), such that a score of 11111 is reflective of full quality-of-life and a score of 55555 is reflective of worst quality-of-life.) 11. baseline 6-minute walk test (6-mwt) is 500 meters or less. 12. supplemental oxygen should be ≤5 l o2/min. 13. if the candidate is either male or female of reproductive potential, he or she must agree to use of double barrier method of highly effective birth control contraception such as condoms with oral contraceptive pill or choose to remain abstinent if already practicing abstinence during the screening period. the duration of required usage of double barrier method or maintenance of abstinence must include the time from the beginning of the screening period until 90 days following the last dose of the study treatment.