inclusion criteria: - age ≥ 18 years - sars-cov-2 diagnosed using real-time reverse transcriptase polymerase chain reaction (pcr) tests or positive for sars-cov-2 virus antigen >90 days before randomization. - still present a chronic symptomatic phase lasting >90 days since debut of symptoms. - have not been hospitalized. - there is no evidence on clinical records of pneumonia or any other organ failure related to sars-cov-2. - capable and willing to provide an informed consent.

inclusion criteria: - age ≥ 18 years - sars-cov-2 diagnosed using real-time reverse transcriptase polymerase chain reaction (pcr) tests or positive for sars-cov-2 virus antigen >90 days before randomization. - still present a chronic symptomatic phase lasting >90 days since debut of symptoms. - have not been hospitalized. - there is no evidence on clinical records of pneumonia or any other organ failure related to sars-cov-2. - capable and willing to provide an informed consent.